Roof truss system with a valley: characteristic features and installation difficulties. Valley roof: what it is, design and installation Valley roof covering

In order for the roof to meet all the architectural features of modern buildings, it is often made in the form of structures from many multi-pitched roofs. Geometrically complex frames rafter system have a large number of junctions of pitched surfaces forming the internal corner of the roof. Such areas in the design wooden roof are called valleys. Another name for this element is a valley or valley gutter. Having a v-shape, the roof valley actually plays the role of a gutter through which water flows are directed and removed. Proper installation This element is of great importance, since installation errors can lead to leaks, damage to the insulation and additional repair costs.

Valley design diagram

Endova is one of the most important and complex elements roof structures. The interface between adjacent slopes is subject to severe climatic loads during operation. When it rains, water flows down it from neighboring slopes, and in winter snow accumulates here.

A properly installed valley not only protects the house from bad weather and precipitation, but also extends the life of the roof.

Typically, the valley consists of a decorative upper strip that covers the junction of two slopes, and a lower gutter, which is located under the roofing.

The number of valleys depends on the design features of the roof, as well as on the presence of additional roof windows.

Depending on the design features of the roof, the number of valleys installed will vary.

The design of the valley involves the construction of a base in the form of a continuous sheathing, on which a layer of waterproofing is laid, as well as the presence of a lower and upper element. The lower valley strip serves as a gutter, and the upper element serves as decorative detail, covering the joints of the slope. Most often, these roofing elements are made of metal. The most quality material for the manufacture of valleys, steel sheets with applied polymer coatings and special coatings are used. In some design options top part valley is not used.

To improve the waterproofing properties of the lower valley, its upper flanges can be sealed with self-expanding porous material

Depending on the angle formed at the junction of the roof joints, there are three types of valleys:

The design of the rafter system, which serves as the basis for installing the valley planks, depends on the intended type roofing. In this regard, there are several types of lathing for laying valley planks:

Continuous sheathing is used when installing soft roofing. In this case, the valley is made in the form of a continuous coating of waterproofing layers. Installing a valley in this way is the easiest.
If, as a roofing covering for two pitched roof slate, profiled sheets or tiles will be used, the sheathing will have a completely different look. For its device use 2 or 3 edged boards, which are mounted along the joints of the roofing covering in increments of 10 cm.
Lathing with additional elements. When using metal tiles, intermediate strips can be installed to the main battens of the sheathing.
The wooden base for the ondulin is made of two boards 10 cm wide, which are mounted in increments of 15–20 cm. Such a base will prevent the valley from sagging.

Video: arrangement of valley and junctions

Valley installation sequence

The valley is installed in the following sequence:

Before installation begins, a drip line is installed along the entire length of the eaves overhang to drain condensate from the under-roof waterproofing.
The drip cap is made of the same material as the main roofing covering
On both sides of the bone rafter with a gap of 5 cm from its edges, horizontal counter-lattice bars are nailed. The lower ends of the bars must be sawed flush with the eaves overhang.
There are increased requirements for waterproofing in the valley area. Three layers of diffusion membrane are laid here. Its task is to protect the underlying structures and thermal insulation materials from moisture, but not to prevent the escape of water vapor. The first layer of membrane is laid out along the valley on top of the horizontal counter-lattice. The film inside the counter-lattice forms a kind of groove that protects the wood from getting wet on the side in the event of under-roof condensation. The membrane is attached using brackets to the top and side edges of the planks. Then the membrane is cut along the edge of the drip and counter-lattice.
The waterproofing material protects the counter-lattice strips from getting wet on the side and is attached to them with a construction stapler.
Next, the diffusion membrane is laid out along the slopes onto the rafters according to pre-made markings. Laying waterproofing on slopes is done in a pigtail, that is, alternately on both sides of the valley. In this case, the membrane is transferred through both horizontal counter-battens and cut off behind its opposite edge. The membrane is also fastened to the slopes using a stapler on the side and top edges of both horizontal counter battens. The joints of this waterproofing barrier can be sealed using double-sided tape.
When gluing the membrane, it is necessary to make an overlap of at least 10 cm and glue it with double-sided tape
To prevent the membrane from flapping against the drip tray from the wind and from fraying over time, it is necessary to glue it to the edge of the drip tray with double-sided tape.
On top of the waterproofing, valley board bars are packed, which form air gap for ventilation of the under-roof space and removal of condensate from the film.
A gap is left between the bottom valley strip and the waterproofing film to drain condensate
Laying the membrane from the opposite slope, as well as fastening it with brackets to the horizontal counter-lattice and gluing it with double-sided tape occurs in the same way.
After both adjacent slopes and the valley are covered with a membrane, the filling of the counter-lattice is completed on them and the installation of the sheathing bars begins. Installation of the lower sheathing along the eaves overhang is carried out flush with the ends of the counter-lattice.
Wooden sheathing laid on counter-lattice bars is necessary for ventilating the under-roof space and for attaching the finishing coating
In the valley area, markings are made on the lower planks of the sheathing at an angle for precise joining with each other. A ventilation strip is installed along the entire eaves to protect against bird penetration.
The bottom battens of the sheathing in the valley area are trimmed to form an even joint
The ends of the sheathing on the side of the gable overhang are covered with a flap of membrane folded up, which is fixed to the bars with a stapler. A frontal board is placed on top of it. If this is provided for in the project, brackets for attaching gutters are installed along the entire eaves overhang.
In the valley area, in the middle between the rows of sheathing slats, additional bars are packed, which support the gutter, preventing it from deforming under the weight of snow. At the same time, thanks to the increased sheathing, the space under the valley groove is well ventilated. If there is a drainage system, a plastic overhang apron is installed. Its task is to prevent water and snow from entering ventilation gap between tiles and waterproofing.
To counteract snow loads under the plank of the lower valley a more rapid sheathing is installed

If there is no drainage system, installing an eaves apron is not necessary.

Video: installation of a valley on a metal roof

Connection of two valleys on a slope

The installation process at the junction of two valleys is carried out as follows:

If the design provides for a junction of valleys below the ridge, then the gutters on both sides are trimmed for a tight fit and secured with self-tapping screws. The junction of the gutters is carefully sealed with sealing tape along the entire length, profiled along the edges and rolled with a roller.
The valley strip in the upper part is attached to the sheathing with brackets. The upper corner of the joint is formed by hand, and the flange is pressed against the surface of the grooves.
To prevent moisture from penetrating into the under-roof space, bends are made along the edges of the valley planks.
The flange is completely bent inward along its entire length, while force can only be applied in places above the sheathing. Along the entire length of the valley groove, foam rubber strips are glued on both sides. They protect the under-roof space from precipitation and dust. The lower edge of the foam strip should be on the overhang aerial element. If foam strips were not used for some reason, water, snow and dust will constantly get under the roofing, thereby reducing the life of the structure.
Foam strips must be installed to protect the space under the valley strip from water, snow and dust
Roofing material is laid on both adjacent slopes in the direction from the gable overhang or valley ridge, covering the groove as much as possible. To ensure unhindered drainage of rainwater and snow removal along the valley gutter, the covering on both sides is trimmed at the same level. The overlap of the trimmed tiles onto the valley groove should be from 13 to 15 cm or 8–10 cm from the center of the bottom strip.
Sheets of metal tiles are cut so that they extend onto the bottom bar of the valley by 13–15 cm

A smaller overlap will lead to the foam strip being destroyed due to exposure to solar radiation, and a larger overlap will complicate the installation of the tiles.

The cutting line is applied with a dye cord along the marks located at the top and bottom of the valley, and is marked on both sides of the groove.

Video: valley with access to a slope on a metal roof

Features of fastening elements of the valley assembly

The valley node looks like a concave angle between two roof slopes. To fasten this roof element, roofing screws are used, which are equipped with a rubber or plastic washer. The washer performs several functions:

protects the surface of the roofing material from scratches and damage;
serves as a waterproofing layer between the self-tapping screw and the hole in the roof, hermetically closing all cracks.

The rubber washer provides soft pressure on the screw and waterproofing of the hole

When installing the valley strip, an overlap of at least 10 cm must be made.

To better seal these roofing elements, it is necessary to use sealing tape.

The lower valley strips are mounted directly to the wooden sheathing using clamps secured with nails or self-tapping screws. The upper element of the valley must be screwed with self-tapping screws to the metal tile. Please note that the screws for fastening the upper valley should not rest against the lower gutter. The gaps between the roofing and the gutter sheets must be filled with foam rubber sealant.

Clamps secure the bottom strip of the valley without damaging its edges

When installing valley units, you should pay special attention to the quality of the sheathing. It is recommended to install the lower gutter on a continuous sheathing, the width of which should not be less width the valley itself.

Installation of valley nodes is carried out as follows:

The brackets should be attached not to the regular sheathing, but to the thickened sheathing, otherwise they will interfere even laying roof tiles

The upper groove is laid on the underlying one with an overlap of at least 10 centimeters. When laying, it is necessary to align the transverse ribs of the gutters and secure subsequent grooves in the same way as the first.

When installing a valley from several planks, it is necessary to make an overlap of 10 cm

Installation of overhang aero element

An overhang aerial element is installed to provide additional support for the bottom row of metal tiles, as well as to prevent birds from entering under the roof.

If the discharge is larger, it will hold debris and fallen leaves in the gutter, and also prevent snow and rainwater from sliding.

Strengthening the valley

The functionality of the valley is directly related to the quality of its foundation. To strengthen the valley, it is better to use continuous sheathing.

A waterproofing layer is installed along the entire length of the base. The best option for strengthening gutter nodes is to use a valley carpet. This protective coating is made of non-woven polyester material impregnated with concrete mixtures with the addition of modifiers. A coating of basalt crumbs is applied to the upper side of the valley carpet, and its lower part is covered with sand granules.
The waterproofing material is fixed using special stickers or nails. If the carpet is nailed, the distance between them should be about 20 cm.
The lower valley elements, roofing, seals and decorative parts are installed.

To strengthen the valley nodes instead standard waterproofing non-woven polyester materials can be used

Installing polyester fabric with bitumen impregnation allows you to solve a number of problems:

provide reliable protection internal kinks of the structure and other places most vulnerable to moisture penetration;
create a shock-absorbing layer that will soften the load from snow;
improve the aesthetic qualities of the roof;
completely eliminate leaks.

Trimming tiles when arranging a valley

If the valley is installed on a tile roof, trimming of the roofing material elements is often required:

First, a rough fit is performed, and then the final marking and cutting of the tiles is carried out exactly along the line marked on the valley groove.
Trimming the tiles must be done on a machine with a circular saw.
A tile spike that hits the valley is knocked off or cut off so that it does not crack at the groove.
The foam strip under the tiles should be trimmed - this allows you to immediately lay the roofing evenly, without waiting for it to push the strip under its own weight and fall into place.
A hole for the self-tapping screw is first drilled in the trimmed tile so that it does not fall into the groove.
The prepared roofing element is installed in place and secured with a self-tapping screw.
All laid elements must form a straight line parallel to the axis of the groove
Sometimes when marking, it is clear that after cutting off some elements, a small triangular fragment remains, which is difficult to secure. This happens if the cut line falls on the right edge of the tile, then the cut line is shifted by 5 cm, and half-tiles are used nearby. It is installed instead of the usual row one column from the trimmed one. The consumption of half roofing elements is one piece per two rows on each side of the valley.
Half tiles add the missing roofing fragment if in this row most of the surface of the last covering element falls under trimming on the valley
The prepared trimmed tiles are laid in place and fixed with a self-tapping screw. The tile from the top row moves down and presses the trimmed element.
The rest of the roofing material in the valley is laid in the same way. When laying on a ridge, the outermost ridge tiles that extend to the junction of the valleys are cut along the same line as the tiles located in rows on the slope.
The upper cut of the outermost ridge tile is closed special tape for junctions. The valley installation is complete.
Corrugated tape is a convenient and effective material for sealing protruding parts of the roof

You cannot fasten tiles through the valley groove, as precipitation will flow under the roof where the self-tapping screw passes.

Video: installation of ceramic tiles - valley formation

Errors when installing the valley

Installing a valley gutter requires care and skill. Since this roofing element carries a large amount of rainwater, the slightest mistake during its installation can lead to serious problems and additional costs. The most common mistakes when installing a valley are:

Attempting to cut tiles directly at the valley using a grinder. This often leads to damage to the already secured groove. In addition, it is very difficult to achieve an even cut line along the entire length of the valley, so the valley and the entire roof will look sloppy, and water drainage and snow removal will be difficult.
If the tiles are cut unevenly, the roof will have a sloppy appearance, and water and snow will flow off it intermittently
Fastening the groove with nails along the entire length.
Installing valley strips from the ridge to the bottom edge. In this case, the lower bar will cover the upper one. At the junctions of these elements, moisture will get inside the roof and not flow down.
Narrow sheathing or lack of additional slats. This mistake will cause the weight of the snow to deform the valley. As a result, cracks and gaps are formed through which moisture can penetrate.
Twisted or insufficiently tightened screws. In the first case, the roof covering is damaged, in the second, moisture will penetrate under the screw.
If the screws are not tightened correctly, water will flow into the under-roof space, contributing to the destruction of the rafter system.

The process of installing a valley requires special knowledge and construction skills. Therefore, it is better to entrust the installation of this roofing element to experienced specialists. In this case, errors that lead to serious problems will be eliminated.

At first glance, installing a valley roof seems to be a rather complex and problematic process. Therefore, many consumers prefer to pay builders rather than do this work themselves. In the article we will further describe in more detail what a valley is, and also provide detailed instructions according to its construction.

Purpose of the groove

On roofs with complex configurations that include several slopes at once, internal joints inevitably occur. Snow precipitation most often accumulates in such places, rainwater, as well as all kinds of garbage. In addition, they are quite difficult to maintain.

The valley, or valley, is an element that is laid along the inner corner of the roof under the slopes. It is designed to protect the structure from water flowing under the roofing and ensures free evacuation of precipitation from the roof surface.

The number of valleys will depend on the following factors:

The roof configuration is cruciform, in the shape of the letter T or G.
The presence of additional elements, in particular, attic and dormer windows.

Structure of the internal valley

As a rule, the construction of a valley made of corrugated sheets involves the presence of two planks, which are bent at an angle coinciding with the angle formed by the adjacent slopes. In this case, the lower element serves as a drain, and the upper one is rather decorative.

In some cases, the top piece of the valley is not installed. This depends on the type of roofing, as well as the features of the roof. Be that as it may, proper execution of the valley connection ensures the reliability and waterproofing of the roof structure.

There are some standards for arranging a valley:

The lower element of the valley is laid before fastening the roofing material, and the upper element - after its completion.
Nails are not used to install the valley.
The gutter is assembled from the bottom up, sealing the seams with Tegola brand bitumen-polymer mastic, sealants based on bitumen (Xtra Seal) or rubber (Tytan), or Icopal glue.
Inner valley for corrugated sheeting it is made of galvanized steel or copper, and the external one is made of roofing material. It is preferable to use a galvanized sheet with a polymer coating; such a valley strip can withstand temperature changes from -60 ℃ to 120 ℃.
To provide additional insulation of the roof and prevent water from flowing under the roofing material, a foam rubber sealing gasket is glued along the ribs of the valley.
The groove can be secured either with clamps on the sides or with self-tapping screws along the edges.
The sides are made at least 2 cm in height so that water does not overflow over them during heavy rain.
The valley flange is in contact with the end parts of the sheathing slats.
In cases where the valley for corrugated sheeting is assembled from several sections, they are laid with an overlap of 10 cm.
On roofs with flat slopes, enhanced waterproofing is required.

Types of grooves and their connections

There are several types of roof valleys made from corrugated sheets based on the configuration of the joints between the slopes:

Open valley - found on low-slope roofs. In this case, additional waterproofing is necessary.
The closed type of valley is characteristic of roofs in which steep slopes practically touch, overlapping the gutter.
An intertwined valley is shaped like a closed valley, however, at the joints the fragments of the roofing intersect, forming a single surface.

Let's look at the features of each type of valley.

An open valley has the following advantages:

No debris accumulates on it.
Sediment is quickly evacuated from the surface.
Installation work is quick and easy.

If we talk about the shortcomings, then such a valley does not look very beautiful.

Among the advantages of closed or interlaced grooves are:

Aesthetics.
High-quality waterproofing.

But this design has significantly more disadvantages:

The intertwined valley is quite difficult to install.
The process takes much longer.
This roof needs regular cleaning of debris.
During thaws, ice plugs may appear between the gutter slats.

Schemes and types of lathing for the rafter system

Depending on the intended roofing material and the design of the rafter system, the construction of the valley will be carried out differently. In this case, we mean the type of sheathing. Recommendations in this regard are usually indicated by manufacturers in the instructions for roofing coverings.

The lathing for laying the valley can be of the following types:

Continuous sheathing is performed for subsequent laying of soft roofing. In this case, the valley roofing carpet executed from waterproofing material. This installation method is the simplest.
A gable roof with a valley, in which slate, corrugated sheeting or tiles are used as the roofing; the sheathing for the gutter is made of 2-3 boards, 10 cm wide, laid along the joints. The wider the valley is supposed to be, the larger the pitch of the sheathing will be.
To lay metal tiles between the main slats, auxiliary battens are installed. Otherwise it won't cause any difficulties.
Ondulin is laid on two 10 cm wide boards in 15 cm increments, so the groove will not sag.

Installation features for corrugated sheeting and other roofing materials

As already mentioned, a house with a valley roof is subject to loads from rain and snow, which must be removed from its surface in a timely manner. In this regard, the arrangement of high-quality waterproofing is a primary task. Therefore, when installing a gutter, you should pay attention to such subtleties as: correct cutting of the roofing material, maintaining the spacing between the supporting elements and fasteners, tightness of the seams, and the size of the overlaps. Only the technology for installing a valley made of soft roofing, which is placed on a continuous base, will be somewhat different.

Installation under a soft roof is carried out as follows:

Placed on a continuous sheathing over the entire surface of the roof slopes underlay carpet. At the joints of individual sheets it is laid with an overlap.
A valley carpet is laid along the inner corner of the roof. Its edges are fixed with bitumen mastic and then nailed every 10-20 cm. About 20 cm of carpet should peek out from under the roofing material.
If the length of the valley exceeds 10 m, it is made of several parts, secured in an overlap of 15 cm. The edges of the planks are secured with mastic.

The technology for installing a valley under corrugated sheets, ceramic or metal tiles is as follows:

A layer of waterproofing is laid on top of the base, which is nailed every 20 cm.
Next, lay the lower element of the valley with a slight overlap of the cornice board, fixing it with self-tapping screws every 30 cm.
Sealing strips are placed along the edges of the bottom gutter strips.
The roofing material is cut along the groove and secured so that it does not reach the bend by 10 cm.
The upper element of the valley is mounted with an overlap of 10-12 cm.

To mark the cutting line, you can use paint cord from KARPO, Irwin, INTERPOOL MT-2507 or STAYER brands.

Installation of a groove for ondulin:

Separate pieces of material for the valley are attached with an overlap of 15 cm using self-tapping screws in the upper corners of each fragment.
The edges of the groove are sealed with sealing tape.
The roofing covering along the corner element is trimmed and then nailed into each wave as far as possible from the middle of the gutter.

Features of the valley design near the roof windows

Roof structures such as attic doors or dormer windows also need to be waterproofed. The construction of a valley in such places involves placing its lower element on the correct covering.

The work flow looks like this:

The sheathing is installed near the attic window.
Calculate the length of the groove, taking into account possible overlaps if it consists of several fragments.
Mark the bend at the bottom of the gutter.
Bend the incised areas in the direction opposite to the sides.
The valley is slightly raised above the roof level by placing bars under it.
The edges are sealed with tape.
The lower section of the roofing covering is trimmed and slipped under the valley strips.

Thus, the valley is an extremely important and required element roofs, which you can arrange with your own hands. It is only important to arm yourself with some knowledge and tools.

Purpose of the groove

On roofs with complex configurations that include several slopes at once, internal joints inevitably occur. Snowfall, rainwater, and all kinds of debris most often accumulate in such places. In addition, they are quite difficult to maintain.

The number of valleys will depend on the following factors:

The roof configuration is cruciform, in the shape of the letter T or G.
The presence of additional elements, in particular, attic and dormer windows.

Structure of the internal valley

There are some standards for arranging a valley:

The lower element of the valley is laid before fastening the roofing material, and the upper element - after its completion.
Nails are not used to install the valley.
The gutter is assembled from the bottom up, sealing the seams with Tegola brand bitumen-polymer mastic, sealants based on bitumen (Xtra Seal) or rubber (Tytan), or Icopal glue.
The internal valley for corrugated sheeting is made of galvanized steel or copper, and the external valley is made of roofing material. It is preferable to use a galvanized sheet with a polymer coating, which can withstand temperature changes from -60 ℃ to 120 ℃.
To provide additional insulation of the roof and prevent water from flowing under the roofing material, a foam rubber sealing gasket is glued along the ribs of the valley.
The groove can be secured either with clamps on the sides or with self-tapping screws along the edges.
The sides are made at least 2 cm in height so that water does not overflow over them during heavy rain.
The valley flange is in contact with the end parts of the sheathing slats.
In cases where the valley for corrugated sheeting is assembled from several sections, they are laid with an overlap of 10 cm.
On roofs with flat slopes, enhanced waterproofing is required.

Types of grooves and their connections

There are several types of roof valleys made from corrugated sheets based on the configuration of the joints between the slopes:

Open valley - found on low-slope roofs. In this case, additional waterproofing is necessary.
The closed type of valley is characteristic of roofs in which steep slopes practically touch, overlapping the gutter.
An intertwined valley is shaped like a closed valley, however, at the joints the fragments of the roofing intersect, forming a single surface.

Let's look at the features of each type of valley.

An open valley has the following advantages:

No debris accumulates on it.
Sediment is quickly evacuated from the surface.
Installation work is quick and easy.

If we talk about the shortcomings, then such a valley does not look very beautiful.

Among the advantages of closed or interlaced grooves are:

But this design has significantly more disadvantages:

The intertwined valley is quite difficult to install.
The process takes much longer.
This roof needs regular cleaning of debris.
During thaws, ice plugs may appear between the gutter slats.

Schemes and types of lathing for the rafter system

The lathing for laying the valley can be of the following types:

Continuous sheathing is performed for subsequent laying of soft roofing. In this case, the valley roofing carpet is made of waterproofing material. This installation method is the simplest.
A gable roof with a valley, in which slate, corrugated sheeting or tiles are used as the roofing; the sheathing for the gutter is made of 2-3 boards, 10 cm wide, laid along the joints. The wider the valley is supposed to be, the larger the pitch of the sheathing will be.
To lay metal tiles between the main slats, auxiliary battens are installed.
Ondulin is laid on two 10 cm wide boards in 15 cm increments, so the groove will not sag.

Installation features for corrugated sheeting and other roofing materials

Installation under a soft roof is carried out as follows:

An underlayment carpet is placed on a continuous sheathing along the entire surface of the roof slopes. At the joints of individual sheets it is laid with an overlap.
A valley carpet is laid along the inner corner of the roof. Its edges are fixed with bitumen mastic and then nailed every 10-20 cm. About 20 cm of carpet should peek out from under the roofing material.
If the length of the valley exceeds 10 m, it is made of several parts, secured in an overlap of 15 cm. The edges of the planks are secured with mastic.

The technology for installing a valley under corrugated sheets, ceramic or metal tiles is as follows:

A layer of waterproofing is laid on top of the base, which is nailed every 20 cm.
Next, lay the lower element of the valley with a slight overlap of the cornice board, fixing it with self-tapping screws every 30 cm.
Sealing strips are placed along the edges of the bottom gutter strips.
The roofing material is cut along the groove and secured so that it does not reach the bend by 10 cm.
The upper element of the valley is mounted with an overlap of 10-12 cm.

To mark the cutting line, you can use paint cord from KARPO, Irwin, INTERPOOL MT-2507 or STAYER brands.

Installation of a groove for ondulin:

Separate pieces of material for the valley are attached with an overlap of 15 cm using self-tapping screws in the upper corners of each fragment.
The edges of the groove are sealed with sealing tape.
The roofing covering along the corner element is trimmed and then nailed into each wave as far as possible from the middle of the gutter.

Features of the valley design near the roof windows

Roof structures such as attic doors or dormer windows also need to be waterproofed. The construction of a valley in such places involves placing its lower element on the correct covering.

The work flow looks like this:

The sheathing is installed near the attic window.
Calculate the length of the groove, taking into account possible overlaps if it consists of several fragments.
Mark the bend at the bottom of the gutter.
Bend the incised areas in the direction opposite to the sides.
The valley is slightly raised above the roof level by placing bars under it.
The edges are sealed with tape.
The lower section of the roofing covering is trimmed and slipped under the valley strips.

Thus, the valley is an extremely important and necessary element of the roof, which you can arrange with your own hands. It is only important to arm yourself with some knowledge and tools.

Construction of the valley: diagram of the rafter system, internal valley for corrugated sheets, connection of the roof of the house

How to make a roof valley

Increasingly, the roof has more than just a functional purpose. Often this element is the highlight of the building. Such roofs have many planes that are connected under different angles. Some connections - with positive angles - are designed in the form of a ridge, some - with negative angles - in the form of valleys. To ensure that the attic is always dry, the roof valley must be done correctly.

Valley roofs

On roofs of complex shapes, when installing protruding dormer windows are formed sharp corners. They are obtained at the junction of two slopes. The junction is called the valley, and the roofs are called valleys.

What is a valley

Roofs of complex shapes look very decorative and are a decoration of the building, but their design and installation is not an easy task - connecting planes is not easy. Due to the design features, these areas of the roof bear a heavy load: there is always a lot of snow and water. Therefore, the sheathing is made reinforced, and waterproofing measures are much more serious than on the rest of the surface.

Features of rafter systems

Rafters from different stingrays in the valley they can be connected at different angles (depending on the shape of the roof). At the junction, a rafter leg is installed, to which the rafters from the slopes are attached. For a short length (up to 2 m), it is enough to fasten them on nails (2 on each side); for a significant length, the joints are reinforced with metal plates.

In places of greatest load (in the widest place), the valley rafter leg is supported from below by a jib.

A support is placed at the bottom at the widest point

At the junction of two roof slopes, reinforced sheathing is required, and its design depends on the type of roofing material:

Under the metal tiles in the valley, intermediate strips are installed - in the middle between the main ones. That is, in this place the step is twice as small. The length of the additional strips must be greater than the width of the bottom valley strip.

Lathing is done twice as often

For corrugated sheets, slate and ceramic tiles, two or three boards are needed on each side

Under the ondulin there should be a gap of 15 cm between the two boards

We have provided typical requirements and sizes, but some manufacturers may have specific requirements. When purchasing roofing material, you will be given instructions that will describe the entire installation process, requirements for the sheathing, and other technical issues. It is clear that you must adhere to their recommendations.

Valley device

There is little point in talking about the device in general, since each roofing material has its own characteristics. Therefore, we will consider the most popular ones separately.

On a metal roof

As already mentioned, lathing is done twice as often under metal tiles at the junction of the slopes. The bottom plank of the valley is laid on this sheathing - this is a galvanized sheet with a fold line in the center and sides along the edges. This element belongs to the accessories and is painted to match the base material. It comes in two-meter pieces.

Metal roof valley

Installation of the valley strip begins from the bottom. The edge of the element extends slightly beyond the roof overhang, is cut 20-30 mm below the overhang, and from this “remainder” a flange (side) is formed. Please note that the valley strip should end behind the overhang; if there is a drain gutter, then above it. If it is made shorter than the overhang, then water will flow into the roof.

The next sheet is laid on top, with an overlap of 20-30 cm, the joint is coated with sealant (you can coat the entire overlap with bitumen mastic). Lay as many sheets as necessary, cut them off near the ridge and secure them.

There are two ways to attach the valley sheet

special screws closer to the edge;
with clamps over the side.

Fastening to the side with clamps

When constructing a valley, the main task is to ensure tightness. From this point of view, the second fastening option is more correct - after it there are no holes left, even if they are covered with a rubber gasket.

One more thing. The bottom bar should have sides on both sides, preferably more than 2 cm in height. They are needed so that water flowing from the slope cannot get under the metal tiles.

A sealing tape is glued to the fixed strip, at a distance of about 20 cm from the bend. It comes with self-adhesive tape. Before installation, the protective coating is removed and the tape is glued. Next, metal tiles are laid, which are cut so that the center of the valley is 60-100 mm. Manufacturers do not recommend placing the cuts closer to the center.

The sheets are attached to the sheathing in the regular places - in the lower part of the oxen 20-30 mm below the step. The distance from the fastener to the bend is at least 250 mm.

After fixing the metal tiles, the roof valley is ready and can remain in this form. But appearance Not everyone is happy with cut sheets. In order to close them there is decorative overlay, which is called the upper valley. It performs a decorative function - it covers the cuts; quite often it is simply not used.

See the following video for details of the valley exit above the dormer window.

Made from corrugated sheets and slate

Under these materials, several boards are laid lengthwise in the valley. A strip of waterproofing is attached to them, which is then connected to a waterproofing membrane fixed to the slopes. The overlap should be at least 10-15 cm, the joints are connected using double-sided tape.

Construction of a valley on a roof made of corrugated sheets

In this case, the sealing tape can be supplemented with sealant. A strip of sealant is applied on both sides of the inflection point of the roof. After installing the roofing material, a large free space remains in the projections of the wave. Water, snow, and debris can get there. To prevent this from happening, fill the gap with sealant, applying it in layers.

In the case of a profiled sheet, there are several options for designing the valley:

Open. This is when corrugated sheets are cut at a distance of 60-100 mm from the bend line. In this case, the bar and cuts are visible. To close this “economy”, a decorative gutter is laid on top of the roofing material, covering the cutting lines. It is attached to the sheathing with nails.

Open valley made of corrugated sheets

Open or closed type You choose the connections of the slopes, the structure of the entire pie remains the same. Only the method of cutting the corrugated board changes.

The structure of a valley roof made of tiles is exactly the same as in the case of a profiled sheet. The difference is that the continuous sheathing must be larger - at least 35 cm wide on both sides of the joint. The fastening of the tiles in the valley has its own peculiarities - some fragments are cut so much that it is impossible to fasten them with a standard lock. Then a hole is drilled in the top of the tile and a soft, acid-resistant wire is threaded through it. Drive a nail into the sheathing, twist a wire onto it and fix the tiles in the required position.

In the case of ondulin, the sheathing for the valley is not solid, but two boards located at a distance of 15 cm from one another, symmetrically relative to the center of the valley. A special gutter is placed between them.

A special gutter is placed between the padded boards

Installation starts from the bottom and moves up. The first sheet of the valley gutter is laid flush with the edge of the roofing material, and the shape is corrected. They are nailed to the sheathing from the top side. The next sheet is laid with an overlap of at least 15 cm.

The upper fragment of the gutter overlaps the lower one by at least 15 cm

After the entire gutter is laid, the installation of roofing sheets begins. First, they trim with a margin - the mark is placed 5-6 cm further than necessary. Cut along the intended line (with a jigsaw or grinder). Place it in place, mark the exact cutting line - along the protrusion on the gutter. Cut it off a second time and put it back in place. Since the ondulin sheet weighs little, all operations are easy to perform.

Ondulin is trimmed twice: first roughly, then precisely

The laid sheet is secured with special roofing nails with a head painted to match the coating. It is necessary to fasten it into each wave, retreating as far as possible from the midline of the valley.

Fastened with special nails

Roof valley: installation, do-it-yourself installation, photo, video

How to properly make a roof valley from metal tiles, corrugated sheets, ondulin and ceramic tiles. Rules for constructing valleys, work order.

Roof valley made of corrugated sheets

The design of the roof plays a very important role in creating the appearance of the house. The imagination of architects sometimes simply amazes the imagination with the intricate shapes of the roofs of individual residential buildings. Many planes made of colored corrugated sheets intersecting at different angles look unusual and original.

But the complexity of the roof also has a downside. When choosing a roof structure, you must always remember that its main task is to protect the building from rain and snow. At the same time, any junction of the roof slopes with each other carries the potential danger of violating the tightness of the roof covering and causing a leak.

One of the most critical places in complex-shaped roofs is the inner corner at the intersection of two slopes. This roofing element is called a valley. It is the valley for corrugated sheeting that receives precipitation from the planes of intersecting slopes. When it rains, a stream of water flows down the valley, collected from large area, and in winter snow always accumulates in it, increasing the load on the rafter system.

Therefore, you need to know how to make a valley correctly and pay special attention to the design of this roofing assembly.

Construction of a valley roof made of corrugated sheets

As mentioned above, the valley is the junction of two roof slopes, forming a gutter. The valley for corrugated sheeting can be of three main types:

In an open valley, the lower parts of the roof covering of the slopes end with a special gutter, the role of which is played by the lower valley strip on the corrugated sheet. It is this that serves to drain water into the gutter.

After installing the corrugated sheeting on the roof slopes, the top valley strip is installed at their junction. This element performs more of a decorative function, covering the edges of the roofing. The figure shows the structure of a valley made of corrugated sheets.

A closed valley for corrugated sheets differs from an open one in that in it the sheets of roofing at the junction are adjusted closely to each other. In this case, the upper valley strip is not installed.

The interlocking design of the valley roof is even more complex. In this design, the sheets of roofing at the junction are placed on top of each other in checkerboard pattern.

For roofs made of corrugated sheets, an open roof valley is most often used.

Construction of a rafter system with a valley

Considering the increased load on the roof at the location of the valley, the reliability of the rafter system at the internal junction of the slopes needs to be given special attention. The roof truss system with a valley is quite complex. It is better to entrust the development of drawings of the frame of such a roof to specialists, but there are several basic rules, if followed, a roof with a valley can be built with your own hands.

Before construction begins there is a lot pitched roof with several valleys, you need to first draw up a plan for the rafter system. To understand how to properly lay a valley, you need to conditionally divide the house into several rectangles. The largest of them is considered the main one, and the roof frame of smaller rectangles will be attached to its rafter system.

At the junction of the main room with the extensions the valley lines will begin. At the support points of the valley rafters, additional crossbars are mounted, which, in turn, rest on racks or spacers. Diagonal ones are installed in approximately the same way. rafter legs hip roof. The most difficult is the installation of rafters for the valley of the attic roof.

The rafters under the valley are mounted in the same way as any other rafters of a pitched roof. The main thing is, before making the valley, correctly connect the slopes and securely fasten them together.

If for corrugated sheeting with a small profile height on the roof slopes it is quite enough to perform the sheathing in increments of 300 mm, then the sheathing under the valley must necessarily be continuous.

How to install a valley on a corrugated roof?

When the assembly of the rafter system is completed and the reliability of fastening all its elements together is checked, the valley can be installed with your own hands without much difficulty.

First, additional bars are installed at the site where the valley is installed in order to make the sheathing continuous. Before laying the valley, additional waterproofing must be done in this place.

A waterproofing tape is laid on top of the roofing membrane in the valley, which should be 5-10 cm wider than the bottom strip of the valley. Sometimes special self-adhesive waterproofing tapes are used, but most often they are simply nailed to the continuous roof sheathing.

4. Valley plank; 5. Sheet of corrugated sheets.

After installing additional waterproofing, a lower valley strip is installed at the junction of the roof slopes. When the angle of the corrugated roof slope is small, it is better to use an enlarged plank. If a regular valley strip has a width of about 300 mm on each side, then the increased one is 2 times larger.

Before installing the valley, measure the length of the internal joint of the slopes. The bottom planks of the valley must be cut so that they overlap each other by no less than 150-200 mm. If the roof slope is small, the amount of overlap can be made even larger.

Installation begins from the bottom section, and each subsequent plank overlaps the previous one. The lower valley strip is installed before the roofing is installed. In this case, sheets of corrugated sheets are launched into the valley, not reaching its axis by approximately 50 mm.

After installing the covering sheets, the valley is installed on the corrugated sheet. The top strip of the valley performs mainly a decorative function. It covers the edges of the corrugated sheets at the point where they are trimmed along the axis of the valley.

Particular attention should be paid to how to attach the valley over the corrugated sheet. Considering that the top strip of the valley is much narrower than the bottom one, fastening it through to the sheathing can break the tightness of the bottom strip. To avoid this, the top valley strip can be secured to the covering sheets using rivets.

How to make a roof valley from corrugated sheets?

You complex roof? Then you definitely need to know how to make a valley correctly. Visit the site and find out how to make a roof valley from corrugated sheets, what its structure is and how to seal it.

It is important to build the valley in such a way as to withstand the natural elements, and also to protect the roof of the house from leaking and, possibly, the roof being torn off by gusts of wind.

What is a valley?

If you finish home construction, then one of the most important matters remains the installation of a valley roof. The valley or valley is the junction of the roof slopes, which takes on the lion's share of the roof loads:

heats up in summer high temperature;
rainwater flows onto this joint;
The snow load here is the highest.

A natural disaster for a house can be prevented or its consequences reduced if the valley firmly holds the corner impact. To correctly calculate the structure of the house or its individual parts, you can contact the specialists of the InnovaStroy company. In order to order a free estimate, you can fill out the contact information and leave a message regarding the estimate parameters on the main page of the company’s website. Going to home page, you need to scroll down the page one row from the top and click the button “Order a construction estimate - free!”

Whole house bottleneck

What is the need correct device valley? The weakest point of any structure remains the place where there is a connection. It is here that all negative external influences on the structure can most quickly manifest themselves. The endova, which connects two, three, and sometimes more parts of the roof, is the bottleneck in the design of any structure, both in the private construction sector and commercial buildings.

An incorrectly constructed or incorrectly calculated valley can cause the beginning of the destruction of the roof, under certain circumstances - the entire roof, and sometimes the entire house. If you approach the installation of the valley unprofessionally, without calculations and certain knowledge, you can get the most negative consequences. If we know in advance what needs to be protected from the house, then we can make sure that long years the junction of the slopes was a reliable connection. The specialists of the InnovaStroy company have extensive experience in successfully carrying out the most complex roofing works, including the installation of a valley roof. You can also order a comprehensive service from the company, including house design, roof and roof repairs, as well as design of a new or reconstruction of an existing roof, installation or full cycle roofing works which will be performed by professionals.

How to build a valley correctly?

No matter what the roof is built from, no matter what material is chosen for the roof, there are general laying rules and a diagram of the valley arrangement:

1. First, attach a continuous sheathing of wood at the junction of the two roof slopes.

2. The valley is reinforced from below with roofing sheet or other suitable building material. It must be waterproof and resistant to temperature changes. This could be, for example, one of the options for waterproofing carpets.

3. The sheathing is first assembled from solid plank flooring.

4. The flooring is covered with an asbestos-cement (slate) tray or a galvanized steel tray. This is also called the lower valley. The edge of the tray should protrude forward, beyond the border of the metal tiles, slate sheets or corrugated sheets. This will ensure the rigidity and reliability of the structure.

5. The last step in building the valley is to lay the upper valley above all roofing sheets. Typically, the upper valley is a part made of the same material from which the entire roof is made. The upper valley is not required element roof, but it gives the building complete aesthetic appearance .

Sometimes laying the upper valley may be abandoned for the following reasons:

it is necessary to organize a large throughput plum;
the passage of melted snow, which often contains particles of branches, leaves and other debris, is better with an open type of valley;
it is necessary to improve the flow of melt or storm water for a roof with a low slope angle.

We talked about the basic rules for arranging a valley, but besides this, they have many features. The most important factor influencing the technology of laying the valley is the roofing material. The valley is, in fact, part of the roof, therefore it should be a continuation of it and match the color and material of manufacture. It is important to observe these technological features when completing roofing work, which we will discuss further. If you carefully read all the tips, you may well try to install a roof valley on your own. If you are not confident in your abilities or you do not have consultants with experience in construction, the best option would be to contact those who know how to build this important part of the house. Our advice will help you understand how the valley works and how to build it correctly, even if you are not a builder, but a customer of the service.

How will endova save the house?

The principle of operation of the valley is based on draining water under the influence of the angles of the slopes:

along grooves, gutters or roof profile, moisture, snow or water flow flows to the valley gutter;
the gutter receives the flow and directs it down the roof;
independently or with the help of a drain, the water flow drains to the ground.

The valley should be, based on the tasks set by the front roof structure:

strong enough to hold the flow of water or the sliding of snow, ice
additionally waterproofed to eliminate possible leakage of the roof near the gutter.

To take into account all the features of valley laying, you should know the simple rules worked out by professional builders.

Construction of a valley roof made of metal tiles

Metal tiles are the modern queen of roofing because they have a beautiful appearance and excellent characteristics. When it comes to constructing a valley made of metal tiles, the roof is formed according to the general scheme that we described above. First, the sheathing is arranged, and then they are laid standard sheet metal tiles, specially prepared in the form of a gutter. From above, after installation of all roofing sheets, the upper valley is also attached.

When installing a valley made of metal tiles, you should remember that the wooden sheathing needs to be made:

continuous, without voids at the joint;
sheathing material - boards no less than 150 by 25 mm;
The width of the sheathing from the center of the joint must be at least 300 mm on both sides.

After forming the sheathing, it is necessary to lay waterproofing - a special mat or any other building material resistant to moisture and loads. The lower valley is secured with self-tapping screws with a pitch of at least 300 mm. The edge of the valley is fixed on top of the cornice, since this is necessary for high-quality water drainage. When connected two edges of the slopes, the overlap should be at least 10 cm. In the gap between the lower valley and the metal tiles, it is recommended to lay a seal that will expand under the influence of heat and seal the connection.

Installation of a valley on a slate roof

Slate is a roofing classic. These corrugated sheets made of asbestos cement are cheap and easy to work with, although more fragile than metal tiles.

The installation of a valley on a slate roof preserves the main stages of installing a valley with metal tiles. A sheet of slate, which is specially prepared at the manufacturer for the lower gutter, is laid on the finished wooden frame frame. The upper valley is laid after installation of the entire roof. The lathing for the slate valley is made of beams with a cross-section of at least 60 by 60 mm. If the roof sheathing can be done with pauses in installation, then the valley requires complete sheathing. A slate piece, usually factory-made, is laid on top of the resulting wooden gutter. Slate blanks begin to be secured with thick and large slate nails from the bottom to the top of the roof.

If there is no such slate figure, you can use a metal base for the lower valley. The slate sheets should cover the edge of the lower valley by 10-15 cm. Sometimes in slate version do not perform the upper valley, to increase the flow of melted snow or large flow water during rainstorms. This scheme is practiced in places with high humidity and specific climate.

Construction of a valley made of corrugated sheets

Corrugated roofing has been used for a long time, although such a covering is not fashionable for houses - it looks too simple. But corrugated sheeting is not losing ground because it is inexpensive and easy to process, which is a very important indicator for any construction project. There are no differences in the installation of the valley compared to metal tiles and slate, although there are some peculiarities. For lathing, you can use a continuous row of boards with a cross-section of no less than 32 by 100 mm and a distance of no less than 50-60 mm from the center of the valley. The valley strip must go under the main corrugated sheeting cover by at least 250 mm.

Other methods of constructing a valley

Roofing is not always made from popular materials. Sometimes it is necessary to make a valley for a soft roof, for example from a roll modified bitumen or other synthetics. In this case, the valley is made either open or by the “undercut” method. A valley carpet is laid on top under the lining carpet. This carpet is coated with bitumen mastic to enhance waterproofing. The carpet is nailed with roofing nails, which are driven in at a distance of no more than 2-5 cm from the edge of the carpet and at a distance from one another no more than 25 cm.

If the valley is laid using the undercut method, no flooring parts are required. A valley is also required in tiled roofing. Tile roofing is complex in design and technique, and therefore requires special attention from the builder. It is important to avoid any gaps in thermal insulation or insufficient insulation. In this case, the valley must have snow-stopping brackets. Laying the valley in a tiled roof is carried out in two ways:

on wood flooring from boards
on a thick wooden sheathing.

The width of the board flooring must be at least 30 cm from the axis of the groove. Laying the groove on the flooring is done before filling the sheathing. Grooves are built from bottom to top.

Important results

The valley device is very important point at the completion of the construction of a house, cottage or outbuilding. The important thing is that its device has many technological aspects that should not be missed:

high-quality waterproofing of the lower valley to preserve the integrity of the roof and durability of operation
maintaining the strength of the sheathing structure to prevent the valley from sagging or breaking

correct selection of materials for installing the gutter, choosing this material taking into account the maximum High Quality and reliability, water resistance;
installation of valley elements by specialists or amateur builders with sufficient knowledge.

If all these points are met, you will get a roof where the valley will do its job. main function– protect from the destructive power of water and keep your home warm and cozy for many years without costly and troublesome unscheduled repairs.

The video will help you with the correct installation of the roof valley.

Increasingly, the roof has more than just a functional purpose. Often this element is the highlight of the building. Such roofs have many planes that connect at different angles. Some connections - with positive angles - are designed in the form of a ridge, some - with negative angles - in the form of valleys. To ensure that the attic is always dry, the roof valley must be done correctly.

Valley roofs

On roofs of complex shapes, when protruding dormer windows are installed, sharp corners are formed. They are obtained at the junction of two slopes. The junction is called the valley, and the roofs are called valleys.

What is a valley

Features of rafter systems

Rafters from different slopes in the valley can be connected at different angles (depending on the shape of the roof). At the junction, a rafter leg is installed, to which the rafters from the slopes are attached. For a short length (up to 2 m), it is enough to fasten them on nails (2 on each side); for a significant length, the joints are reinforced with metal plates.

In places of greatest load (in the widest place), the valley rafter leg is supported from below by a jib.

A support is placed at the bottom at the widest point

At the junction of two roof slopes, reinforced sheathing is required, and its design depends on the type of roofing material:

Under the metal tiles in the valley, intermediate strips are installed - in the middle between the main ones. That is, in this place the step is twice as small. The length of the additional strips must be greater than the width of the bottom valley strip.

Lathing is done twice as often

For corrugated sheets, slate and ceramic tiles, two or three boards are needed on each side

Under the ondulin there should be a gap of 15 cm between the two boards

Valley device

There is little point in talking about the device in general, since each roofing material has its own characteristics. Therefore, we will consider the most popular ones separately.

On a metal roof

Metal roof valley

There are two ways to attach the valley sheet

special screws closer to the edge;
with clamps over the side.

Fastening to the side with clamps

One more thing. The bottom bar should have sides on both sides, preferably more than 2 cm in height. They are needed so that water flowing from the slope cannot get under the metal tiles.

The sheets are attached to the sheathing in the regular places - in the lower part of the oxen 20-30 mm below the step. The distance from the fastener to the bend is at least 250 mm.

After fixing the metal tiles, the roof valley is ready and can remain in this form. But not everyone is happy with the appearance of the cut sheets. In order to close them there is a decorative overlay, which is called the upper valley. It performs a decorative function - it covers the cuts; quite often it is simply not used.

Made from corrugated sheets and slate

Construction of a valley on a roof made of corrugated sheets

In the case of a profiled sheet, there are several options for designing the valley:

Open. This is when corrugated sheets are cut at a distance of 60-100 mm from the bend line. In this case, the bar and cuts are visible. To close this “economy”, a decorative gutter is laid on top of the roofing material, covering the cutting lines. It is attached to the sheathing with nails.

Open valley made of corrugated sheets

You choose the open or closed type of connection of the slopes; the structure of the entire pie remains the same. Only the method of cutting the corrugated board changes.

A special gutter is placed between the padded boards

The upper fragment of the gutter overlaps the lower one by at least 15 cm

Ondulin is trimmed twice: first roughly, then precisely

Fastened with special nails

Tin roofs

In private housing construction, this type of roofing material is rare, however, there are such roofs. The tin roof valley is connected manually, using a mallet and a special tool.

Roof valley: installation, do-it-yourself installation, photo, video

How to properly make a roof valley from metal tiles, corrugated sheets, ondulin and ceramic tiles. Rules for constructing valleys, work order.

Roof truss system: device features

When building a private house, bathhouse or utility buildings, the roof truss system requires a special approach. It is important to perform the calculations correctly and prepare high-quality material for installation.

Design of truss structure

The calculation of load-bearing structures in construction is usually performed using the limit states method, i.e. at the moment of loss of resistance of the structure under the influence external loads up to destruction or unacceptable damage.

The rafter system reaches limit state, If:

the strength of the structure is completely exhausted and it collapses;
Deflections of the elements of the supporting frame provoke unacceptable violations in the nodes of the rafter system, and further operation of the roof is impossible without repairs.

According to building codes, the maximum permissible deflection of a rafter leg or tie is 1/200 of the length of the element. To ensure high reliability of the structure, it is recommended to design the roof taking into account the maximum permissible deflection of 1/250 of the rafter length.

The calculation of the roof truss structure is carried out taking into account ultimate loads from the outside:

own weight;
wind pressure;
snow weight;
the weight of people servicing or repairing the roof (the load from a person is usually taken as 80 kgf/sq.m).

To obtain information on the basis of which calculations are made, it is necessary to have:

SNiP for roofing structures;
table for calculating the cross section of the rafter leg;
table of cross-sections of rafters;
climate map of the region (determination of wind and snow load).

The cross-section of the timber from which the elements of the rafter structure are made is calculated using a special formula, which takes into account the length of the rafter leg, the pitch between the rafters, and the resistance of the selected type of wood to external loads.

Tables for selecting sections of elements are used when designing simple roofing structures. Developing a roof project of complex shapes requires a professional approach.

Knots of the rafter system

The reliability of the truss structure is influenced by the following factors::

correct choice of rafter system configuration;
strength of connections in structural units;
accuracy of engineering calculations when designing a roof;
correct choice and quality of materials;
installation quality.

The type of rafter system, the presence of certain nodes of elements is dictated:

designed roof shape;
dimensions of the overlapped space;
the presence and location of internal supports or load-bearing walls.

When building houses with a usable attic or attic floor usually used rafter structures with layered rafters. Their main nodes include:

support unit for rafter legs;
ridge knot;
“rafter-strut-post” assembly;
“beam-post strut” assembly, etc.

When designing, it is important to immediately decide on the methods of fastening the elements. The choice depends on some features of the lumber, as well as the preferences of the people conducting construction work.

Key stages of roof construction

Installation work begins after the preparation of the project, which indicates all the dimensions of the elements and their relative positions, as well as the principles of connection. In addition, you should purchase and bring the necessary building materials, tools, fasteners, etc.

The principles of constructing a pitched roof, in general, do not depend on its configuration. The work technology includes the following steps:

Laying the Mauerlat. The support beam is laid on waterproofing (roofing felt or other moisture-proofing material), which protects the wood from rotting. To fasten the Mauerlat to the wall, wire embedded in the masonry can be used, or clamps can be used to attract the timber to the anchors in the wall, but preference should be given to studs mounted in a monolithic concrete beam.

The length of the free end of the studs must exceed the thickness of the mauerlat beam by a distance that allows the nut to be screwed on. The studs can be staggered (but not necessarily) with a pitch of at least 2 meters. To prevent the stud from being pulled out of the concrete, its recessed end should be bent.

Installation of front (outermost) rafters. When building a roof truss system with your own hands, it is very important to install the main rafters strictly vertically and at the same level; the correctness of the planes of the slopes and, accordingly, how evenly the load on the roof will be distributed depends on this.

Depending on the selected roof configuration, at this stage we also install ridge run, which must be strictly horizontal. The purlin rests on special vertical posts or is attached to the gables. If mounted hip roof, the key point is the installation of diagonal rafters.

Features of a roof with a valley

The construction of a roof truss system of complex shape (multi-gable roofs) requires the creation of connections for ridges and slopes. The planes of the slopes can have different geometric shapes: triangle, rectangle, trapezoid. The endova is the junction of the slopes with the formation of a negative angle.

In the house plan, roofs with valleys look cruciform, T-shaped or L-shaped. These are the two main ways to create roof junctions. At the design stage, a roof plan (top view) is drawn up, taking into account attic and dormer windows, all junctions, roofs over terraces or verandas, indicating all linear dimensions. The general plan of the roof is divided into rectangles and squares; the main rooms and extensions are indicated on it.

On the roof plan, the main purlins should be indicated, and in the perpendicular direction, the secondary purlins over smaller rooms should be indicated. Then lines are drawn connecting the corners of the roof above the secondary rooms with the corners of the main roof. These diagonal lines indicate the location of the valleys - the internal corners formed by the junction of the slopes.

When installing a rafter system, the valleys at the joints of roofs of the same height (i.e. if the ridge girders are located at the same level) are diagonal rafters, resting with the upper end on the ridge girder and the lower end on the mauerlat. The installation of such rafter legs is carried out similarly to the installation of diagonal rafters for a hip roof.

Depending on the size of the extensions, the angles of the roof slopes can have different values. The geometry of the roof can be changed by shortening the size of the purlins. The angle of inclination of the valley changes accordingly. The roof truss system with a valley can be made using a spacer or non-spacer method. If spacer rafters are installed, then to relieve excess stress, a horizontal tie should be secured at the bottom of the structure.

Installation of the valley

The design and installation of a roof with valleys is quite complex. In this case, mistakes can lead to roof collapse or leaks. One of the purposes of the valley is to ensure the removal of precipitation. Valleys differ in their design:

To install a valley on mating slopes, it is necessary to install a continuous sheathing. Waterproofing is laid along a wooden gutter - it is better to lay it in two layers. Then the valley is secured with self-tapping screws. If its joints are horizontal, the overlap should be at least 100 mm (recommended value - 300 mm). If the valley is mounted on a slope with a slight angle of inclination, it is recommended to add another layer of waterproofing, and when installing the valley on a metal tile roof, additionally use a self-expanding sealant.

An open-type valley is easier to install and removes precipitation better. Closed and interlocking structures are typically used on steeply pitched roofs covered with certain roofing materials. Their disadvantages include increased costs for additional waterproofing and some installation difficulties. Intertwined and closed valleys drain precipitation worse, and in cold climates in winter they serve as a place for accumulation and compaction of snow.

Do-it-yourself roof truss system, device with a valley, video

Construction and design of the roof truss system. The sequence of installation of the rafter system and the features of the roof with a valley along with the video.

Rafter system for a roof with a valley

Make a gable or pitched roof quite simple. Although it will perform its main function, it will not be attractive from an aesthetic point of view. Recently, designs with several slopes and protrusions are gaining great popularity. At the junction of two slopes, a node is formed, which is called a valley. This part of the roof requires special care during design and installation. From the article you will learn the features of a valley and how to make it yourself.

Design and varieties

Only the inner corners of the roof are called the valley. Buildings that form a T or L shape cannot be built without this element. In addition, similar corners are formed in the places where dormer windows emerge, protruding parts of the attic and other architectural delights.

The main task of the valley is to protect attic space from moisture penetration. The fact is that in this place the roof is experiencing increased loads due to the large amount of precipitation that accumulates there. In winter, snowdrifts form here and the structure can sag under increased loads.

The internal corner is assembled from two planks, and each is created for its own purpose:

Bottom. In accordance with its name, it is located under the roofing. Attached with self-tapping screws to the cornice board. She does the basics protective functions to contain moisture at the junction of the slopes.
Upper. In internal corner It is difficult to beautifully design the convergence of roofing material. Therefore, a second strip is mounted on top, which has only a decorative function.

The valley material usually matches the main covering on the roof. In some situations, it can be replaced with a sheet of galvanized steel. It is important to choose metal with a protective coating, since it will often come into contact with aggressive environments.

When constructing a valley, it is important to follow all the rules for the construction and installation of rafters. If one of them is neglected, then there is a threat of frame collapse. However, the standards differ for various types designs. Depending on the roofing material used, one of two types of frames is used:

Articulated and closed. Used on slopes with a large slope angle and for roofs made of flexible material, for example, soft tiles. This type requires the installation of additional layers of waterproofing.
Open. Here the slopes connect to each other at a flatter angle. The joint is closed with a special gutter through which precipitation flows. This design does not require special expenses for the installation of excess waterproofing.

Features of the rafter system and sheathing

Depending on the slope of the slopes, wooden rafter legs are attached to the valley at a certain angle. However, for each side this indicator may differ from the other. Where the beams meet, a thicker rafter is installed. The method of fastening to this place depends on the length of the rafters. If it is less than two meters, then nails are enough, otherwise metal pads will be needed for reinforcement. Before installing the valley, the place of the greatest load is calculated, and a supporting jib is installed there.

Where the slopes meet, it is necessary to strengthen the roof sheathing. How much reinforcement will need to be done depends on the type of roofing:

Metal tiles. In order for the corner to withstand the load, additional ones are fixed between the planks of the main sheathing. Thus, in a critical place the step is halved. It is important that the length of the sheathing be greater than the width of the valley plates.
Profiled sheet, ceramic tiles and slate. For these materials, boards with a width of more than 100 mm are mounted along the mating axis. The number of boards depends on the width of the substrate; two or three pieces may be needed on each side.
Ondulin. The valleys are set back 75 cm from the central axis and fixed one board at a time less than 100 mm wide. A special groove should be placed in the resulting space.
Soft roof. For this material, the lathing is made solid and there is no need to reinforce it in any way.

Frame structure

The main part of the roof valley is attached to a slanted rafter, which on one side rests on the ridge and on the other on the mauerlat. In some cases, for example, when installing a skylight, the mounting locations may change. Depending on the type of roof, the height and shape of the ridge varies. This applies to both the main and secondary structures.

To change the geometric shape of the roof structure, it is enough to lengthen or shorten the run. Along with these manipulations, the slope of the valley will change.

The valley rafter system is assembled as follows:

Attach the purlin from the secondary one to the rafter post of the main roof structure. Pins are used for connection.
The rafters are fastened using nails driven in at an angle. This connection meets all safety requirements and can withstand sufficient load.
Install an inclined rafter from the place where the purlin is attached to the mauerlat.
Sprigs are attached to the inclined rafters. For connection, support bars are fixed in advance at the points of contact.

The abutting flanges transfer high compressive stress to the diagonal rafters. Because of this, the beam heavily loads the joint of the mauerlats. To reduce the pressure from the inclined stoprail to the post to which the secondary roof purlin is attached, stretch the connecting tie. It works in tension and does not allow the valley stop to squeeze out the mauerlat. If the roof is hip, then the tie is connected between two diagonal rafters.

In addition, if under some circumstances the main ridge loses its fulcrum, the tightening will act as a thrust. So, it can prevent emergency roof destruction.

The tightening or grip must be placed at the base of the valley, since in a high position it will stop working in tension. In this position, the beams work in compression and are called crossbars.

As you can see, the rafter system for the valley is not particularly complicated and you can install it yourself. At the same time, it is important not to make a mistake in choosing the cross-section of the beam and the reliability of fastening. Then you will assemble a unique roof and it will last for several decades without leaks.

Roof with valley and rafter system: how to install

Design and types of rafter system for a roof with a valley. Features of laying the sheathing and a description of the frame structure.

Valley plank - what is it and how to install a valley plank + sheathing and rafter diagram

A properly equipped roof of a house is an important component, providing protection to the building from winds, precipitation or sunlight.

The main load falls on the roof, as on the outer plane, which has direct contact with all weather or climatic manifestations.

Any defects in the design of the roof mean the possibility of water getting inside, the formation of centers of destruction of the rafter system or the danger of demolition of the roof due to gusts of wind.

Therefore, the correct use of all elements of the roof covering, which form a sealed layer that reliably separates inner space from contact with the atmosphere, is an important and responsible part of the roof design.

Roof coverings are divided into two groups:

The actual coating, i.e. leafy or roll materials, in the set creating the plane of the slopes.
Extensions - all design elements of junctions, transitions, gutters, etc.

At the same time, it is the additional elements that require the most careful, responsible approach to installation, since they often take on most of the load for draining or removing rain or melt water and snow. One of these elements is the valley.

What is a valley

A roof valley (sometimes a valley) is a term that has two meanings. First of all, This is the area of the roof where two planes meet, forming a depression. This - general concept, defining the meaning of the term, its meaning. In construction practice, another, narrower meaning of the term is used: this is what they call type of additional elements made to design the joint of planes. The presence of two interpretations sometimes causes some confusion caused by confusion of the two concepts due to lack of awareness.

Valleys (in a general sense) are of three types:

Open.The place where the planes meet does not have a tight seam and is covered on top with an additional strip.
Closed. The joint is tight and straight.
Intertwined. A tight joint with transitions of elements of the roofing material pattern onto each other in an alternating order.

The second and third types are much less common, since their construction requires workers with experience and special knowledge. At large selection roofing materials commercially available and different properties and the specifics of installation, find people who know how to design complex roofing elements, not easy. In addition, all work is carried out in difficult conditions, at altitude, which creates additional difficulties.

It should be taken into account that in any case it is not possible to achieve complete tightness of the connection, and the meaning of all efforts, in fact, comes down to achieving a purely decorative effect, which often means a waste of time and labor.

Valleys as an additional element are also divided according to the method of installation:

Bottom end. The internal valley is installed before laying the roof, since it is located under the general layer. In any case, with any type of valley design, the bottom strip is present as a mandatory element, since it is it that serves as a gutter that drains water into the drain. Without it, the junction of the planes will be a continuous gap.
Endova upper. This element is installed on top of the roofing material and serves, firstly, to create visual completeness, neatness of the connection, and secondly, it prevents the accumulation of various debris in the recess of the roof. Any foreign objects, pine needles or fallen leaves, small debris, etc. will gradually create a barrier to the free flow of water, so it will find a way out in another place, which will definitely create a problem. The presence of a top bar prevents such accumulations.

Both types of valley strips have their own installation features. Each type of roofing material has its own set of additional elements, fully consistent with each other both in constructive and design terms, so before installation you should familiarize yourself with the rules and features of working with this material.

What is a roof valley: photo

What are valleys made of and what roofing materials are they used for?

For the manufacture of valleys, the same material is used as for the main one. coatings - asbestos cement is used for slate, for metal tiles or corrugated sheets - galvanized steel sheet, etc.

If a protective coating is used to protect the material from corrosion, as is done in the production of metal sheet materials, then valleys are similarly provided with a layer of protection.

That is, complete compliance of elements is achieved, which when assembled look like parts of a single whole. However, in some cases they resort to using additions of one type to decorate the material of another.

Most often, this combination occurs during the construction slate roofs, since asbestos-cement elements are not as common as other components. Exiting the situation in this way, of course, somewhat affects the aesthetic perception of the roof, but functionally everything works correctly.

Anyway, Fully matching components are created for all sheet roofing materials, allowing you to design all areas of the roof, and valleys in this sense are no exception. It makes no sense to use them for working with soft roll coverings, since their installation technology involves completely different actions, and sealing corners does not require additional structures.

Diagram of the rafter system at the site where the valley is installed

The rafter system at the points of transition of one plane to another must provide straight and even lines without depressions or distortions, which could cause incorrect installation valleys.

The device for connecting two valleys on a slope can be of the following types:

Butt. With this method, rafters of different slopes are connected with their ends at an angle. Careful calculation and accuracy in work are required to avoid bending or distortion.
overlap. The rafters do not connect to each other, being placed “at random”. This option provides a greater guarantee of maintaining a clear transition of planes and maintaining straight lines.

Rafter system for the valley

For correct and precise installation of rafters First of all, you need to designate the runs - the lines connecting the planes. This is done using a stretched rope between the two extreme points of the run and is oriented along this line when assembling. With due care and attention, the design turns out smooth and suitable for performing its functions.

An important element of the valley rafter system is the sheathing. At the junctions it is made continuous, with mandatory waterproofing. Installation of the bottom strip should be done on a flat, straight area so that the pressed strip does not receive any deformation.

Any bending will cause the protective coating to peel off., which will automatically start corrosion processes and cause rapid failure of the bar. If we take into account the presence of a layer of insulation and waterproofing, lining the inner surface of the attic, etc. finishing coatings, detection of damage to the plank will not occur immediately.

By that time, significant damage will have been caused due to water penetration into the roofing materials and elements of the rafter system. Replacing the strip will also require serious work, as well as a lot of time.

Installation of the valley

How to install the additional element correctly:

First of all it is necessary make sure that the substrate is constructed correctly and accurately, that there are no distortions, and that the structure is strong. Loads on valleys can be significantly higher than on flat areas of slopes, since it is in the gutters that snow accumulates, creating strong pressure on the system.
Wooden elements rafters and battens are treated with an antiseptic and the area is waterproofed. It is an additional operation for the valley, general waterproofing roofing materials - another position.
The bottom strip is being installed. The procedure is carried out from the bottom up, the individual parts are overlapped with an overlap of 10-20 cm. All joints are treated with sealant.
The roof is being laid. The joints between the material and the bottom strip are additionally sealed.
The top bar is installed.

How to make a roof valley

All connections are made using roofing screws equipped with a gasket made of special wear-resistant rubber. All areas of possible leaks are treated with sealant.

Other types of additional elements

In addition to valleys, other roofing elements are also manufactured. Any area that requires additional decoration has a corresponding additional element.

Exist the following types of additional elements:

So, we have fully answered the popular question - what is a valley and how to install additional material correctly. All elements have clearly defined functions; their use is an important and irreplaceable stage in the construction of a roof. Most often, attempts to somehow replace ready-made additional elements with handicraft or non-standard parts lead to design inconsistencies and failure to fulfill their purpose. Saving in this case leads to large losses later.

The design and functional features of the valley are to ensure effective drainage and the aesthetic appearance of the valley roof. The elements available on the market allow us to fully solve both issues, provided that they are installed correctly and carefully. It is quite possible to carry out the work yourself, the main thing is to familiarize yourself with the procedure and the specifics of the material and do not forget about safety measures when working at height.

Valley - what is it (photo), installation of the connection of two valleys on a slope (upper and lower), installation of sheathing and rafters

In this article you will learn what a valley is, as well as the types of valley: upper and lower, internal and external. Diagram of the arrangement of valley strips on the roof, consider the connection of two valleys on the slope, the design of the sheathing and rafters. Let's talk about how to properly install a valley roof + photo.