Insulation of the valley. No losses: combating cold bridges in the attic roof structure

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 by 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 roof covering and ensures free evacuation of precipitation from the roof surface.

The number of valleys will depend on the following factors:

1. The roof configuration is cruciform, in the shape of the letter T or G.
2. 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 roof covering, as well as the features of the roof. As it were, competent execution Valley connections ensure reliability and waterproofing roofing structure.

There are some standards for arranging a valley:

1. The lower element of the valley is laid before fastening the roofing material, and the upper element - after its completion.
2. Nails are not used to install the valley.
3. 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.
4. 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; such a valley strip can withstand temperature changes from -60 ℃ to 120 ℃.
5. To provide additional insulation of the roof and prevent water from flowing under roofing material, a foam rubber sealing gasket is glued along the valley ribs.
6. The groove can be secured either with clamps on the sides or with self-tapping screws along the edges.
7. The sides are made at least 2 cm in height so that water does not overflow over them during heavy rain.
8. The valley flange is in contact with the end parts of the sheathing slats.
9. In cases where the valley for corrugated sheeting is assembled from several sections, they are laid with an overlap of 10 cm.
10. 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.
• Closed type valleys - inherent in roofs in which steep slopes practically touch, layering on 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:

1. Aesthetics.
2. High-quality waterproofing.

But this design has significantly more disadvantages:

1. The intertwined valley is quite difficult to install.
2. The process takes much longer.
3. This roof needs regular cleaning of debris.
4. 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 design rafter system The valley device will be performed 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:

1. Continuous sheathing is performed for the subsequent installation of soft roofing. In this case, the valley roofing carpet is made of waterproofing material. This installation method is the simplest.
2. Gable roof with a valley, in which slate, corrugated sheeting or tiles are used as 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 sheathing pitch will be.
3. To lay metal tiles between the main slats, auxiliary battens are installed. Otherwise it won't cause any difficulties.
4. 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, arrangement high-quality waterproofing is a top priority. 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:

1. An underlay 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.
2. 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.
3. 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:

1. A layer of waterproofing is laid on top of the base, which is nailed every 20 cm.
2. 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.
3. Sealing strips are placed along the edges of the bottom gutter strips.
4. The roofing material is cut along the groove and secured so that it does not reach the bend by 10 cm.
5. 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:

1. 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.
2. The edges of the groove are sealed with sealing tape.
3. 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:

1. The sheathing is installed near the attic window.
2. Calculate the length of the groove, taking into account possible overlaps if it consists of several fragments.
3. Mark the bend at the bottom of the gutter.
4. Bend the incised areas in the direction opposite to the sides.
5. The valley is slightly raised above the roof level by placing bars under it.
6. The edges are sealed with tape.
7. 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.

Building your own house, every owner wants his home to look different from everyone else’s: differences are conceived as appearance, and in planning. A house can acquire an unusual look with the help of complex roof shapes, for example, with a valley. The more valleys there are on the roof, the more complex the design.

What is a valley?

Let's discuss what a roof valley is. This is the connection that forms the angle between the planes of the roof. Its main task is to drain water from roofs and other surfaces.

The valley bears the main load during precipitation, so the installation of such a connection should be approached with great responsibility.

Upper outer and inner lower valley. Types and features

The lower valley has the task of protecting the joint from water entering the under-roof area. It has folds at the edges necessary to prevent water overflow. Decorative element, which serves to hide the internal joints of the corrugated sheet and metal tiles, is the upper valley. Unlike the lower valley, it is attached above the sheets of metal tiles.

The roof valley can be open, closed or interlaced. The open valley is designed in such a way that water flows down on its own. However, roofs with steep slopes and twisted panels require a closed or interlaced valley.

The only difference between an interlocking valley and a closed one is that the roofing rows of material are not just laid, but also intertwined. Their disadvantage is the need to lay an additional waterproofing layer.

Design

Valley design diagram: 1 – Tile; 2 – Lathing; 3 – Counter-lattice; 4 – Eurofilm – waterproofing; 5 – Insulation; 6 – Vapor barrier; 7 – Aluminum painted gutter; 8 – Valley flooring; 9 – Foam rubber strip of the valley; 10 – Valley fastening bracket; 11 – Galvanized nail; 12 – Lower roof.

Most popular material Metal sheets are used to make the valley. Galvanized steel will be the most practical solution, extending the entire life of the structure.

The valley design includes two strips: upper and lower. The lower one is installed at joints that form negative angles, and before laying the roof covering. The upper valley strip is installed only after the final completion of the roofing work.

Construction and installation of the valley

• Laying the groove on the flooring should be done before filling the sheathing, after which the edge of the sheathing is nailed to the flooring.
  Before installing the valley, it is necessary to arrange wood flooring under her groove. To do this, use an edged antiseptic board. Its width should be at least 30 cm from the axis of the groove, and its thickness should be the same as the thickness of the counter-lattice. The bonding of the boards is carried out exclusively on the rafter legs.
• It is necessary to bend the side edges of the groove at an angle of 90° and profile them along the block.
• Next, bend the groove along the central axis at an angle that is slightly larger than the valley angle. Special material There is no need to purchase any for this procedure; available products will do.
• Laying the grooves begins from top to bottom. After laying the gutter on the deck or other surface, cut it to the size you need, leaving 3-4 cm for the gutter.
• The overhang on the groove from the edge should be about 8–10 cm for secure fastening of the edges. The flange in this place must be completely bent inward.
• Use staples or nails to secure the groove to the decking. It is necessary to use nails of size 2.8x25 mm. To prevent longitudinal displacement of the groove, you need to nail it to the flooring, while stepping back about 2 cm from the edge.
• The next overlap of the groove should be at least 10 cm. Align the transverse ribs when laying.
• The protective strip must be removed and carefully glued to the edge of the groove. Such self-adhesive strips, impregnated with a special mixture for better moisture removal, provide the best protection from getting excess debris under the tiles.

The photo shows the roof valley

• Special waterproofing measures should be taken if a large amount of moisture has accumulated in the valley sector.
• The sheets coming from the slopes must be applied with an equal overlap, tightly secured with roofing staples.
• The overlaps in the valley are sealed to prevent tearing of the roofing material under the influence of water.
• In cases where large slope angles or large volumes of precipitation are expected in long valleys, several layers of film should be used.

- This is one of the places most prone to leakage. It is impossible to save on valleys, so it is worth thinking about what material to choose for a high-quality joint corner.

For example, the installation of a valley on roofs made of ondulin is made from additional materials that can be purchased in the same place where the ondulin itself is purchased.

Special layers of sheathing need to be installed under the valleys.

List of factors to consider when installing a valley:

• the joints of the slopes should be covered with continuous sheathing;
• a layer of waterproofing must be laid along the length of the open valley gutter;
• if the valley consists of horizontal joints, all elements are laid with a 10-centimeter overlap;
• If the angle is slightly inclined, a backup layer should be laid.

Valley waterproofing

Waterproofing along the valley must be done in accordance with the rules, in particular with allowances for water and debris that may enter the roof. There must also be no damage to the waterproofing (tears or mechanical defects).

One of the important features of waterproofing installation is that it begins immediately after fixing the first row of material.

Endova- a beautiful and functional roof element that you can install yourself using simple instructions.

Remember, that:

• install the valley on rafter elements it is necessary so that the water from the tiles flows exclusively into it;
• an open valley is less labor-intensive to manufacture, but an intertwined valley looks more aesthetically pleasing;
• you need to use several layers of film for better waterproofing.

You can see an example of a valley installation in this video:

Long-term practice of roof construction in Germany has shown that when installing waterproofing layers of a roof structure, much depends on the quality of the work. The very fact of using high-quality materials does not guarantee reliable under-roof insulation. We bring to your attention advice on carrying out this type of work.

The roof must work even in emergency situations. Along with the installation of the roof covering, additional complex solutions used for the lower (under-roof) layers of the roof structure make it possible to ensure complete tightness when exposed to rain or melt water. We will demonstrate how to increase the customer's interest in certain problems when installing a roof.

Device lower parts roof construction is one of the most important tasks of roofers and carpenters, despite the fact that the “Rules for the Construction of Tile and Slate Roofs” of the German Roofing Association refer to work on the underlying layers as so-called additional measures. These works must be carried out depending on the slope of the roof, the roofing material used or if there are any special requirements. The Rules contain a minimum set of measures; at the same time, a more complete list of works is acceptable, and often even desirable. Roofs of complex shapes and roofs of houses located in regions with complex climatic conditions

Complex under-roofing systems are not only temporary emergency roofing. Their main task is to, together with the roof covering, ensure its complete waterproofness throughout the entire period of construction and operation of the building. Long-term practice shows that after laying a hard roof covering, under-roof waterproofing systems reliably cope with this function, despite the places of nail fastenings available in them, adjacent to skylights and various roof penetrations. The use of special sealing tapes or other materials of similar purpose will avoid leakage and, as a result, possible conflicts with the customer. Such implementation of nail connections must be calculated separately and indicated as Alternative option in the estimate documentation.

As a rule, sealing tapes are made from polyurethane foam with a water-repellent modified acrylate impregnation. The tapes are very easy to use, as they are self-adhesive and come with a strong reinforcement of the adhesive layer. Elastic foam material reliably ensures tightness of the nail fastening area and allows you to level out some unevenness in the base made of wooden planks. If OSB board or plywood is used as the base, then less expensive butyl rubber tape can be used. The width of the sealing tapes must be at least 50 mm (this is standard width counter-lattice bar). Thus, water does not even approach places where there are violations of the waterproofing layer (Fig. 4). As a sealant for the counter-lattice, you can also use special adhesives that are resistant to temperature changes and moisture.

Rice. 3. Lack of sealing tape causes roof leaks

The use of such tapes is simply necessary on those roofs where a small angle of inclination is combined with the presence of long valleys, especially on southern slopes. Large amounts of snow and ice will accumulate in the valleys, and frequent thaws will lead to the formation of a significant volume of meltwater. Some of this water will certainly penetrate under the roofing material (ceramic or cement-sand tiles, small-format metal tiles, natural slate) and end up on the layer of under-roof insulation. Problems with melt water leaks also occur on roofs made of bitumen tiles (the so-called soft tiles), especially at the junctions of strips. If corrugated sheets or metal corrugated sheets are used as roofing material, then the overlaps of the sheets must be sealed using sealants or connecting tapes.

Another additional measure should be gluing horizontal and vertical membrane overlaps on flat roofs. For this purpose, all leading film manufacturers offer special adhesives and tapes or membranes with self-adhesive strips already applied. The latter option is more preferable, as it ensures a flawless and durable connection of the rolls. For example, the new DELTA®-FOXX diffusion membrane from DORKEN, which has two zones of adhesive, can be glued to overlaps during rain or melting snow conditions. The special structure of the adhesive layer with drainage channels allows for drainage melt water even if for some reason the roofers were unable to glue the overlaps to the full width (Fig. 5).

Rice. 4. Professional solution - sealing self-adhesive tape

The roofer must explain the essence of the problem to the customer in advance so that he can independently decide on the advisability of using sealing tape and adhesive for film overlaps at his site. As for roofers, by writing such nuances they once again confirm high level their professional competence and protect their interests in case the customer refuses the proposed recommendations. Additional measures for the waterproofing layer expand the capabilities of architects and designers, who will be able to create roofs with lower slopes and piece roofing materials from natural or metal tiles, solid tiles and slate.

Rice. 5. Waterproof diffusion membrane overlap joint with built-in self-adhesive tapes

How to properly arrange valleys

Additional measures given in the instructions for professionals should ensure complete tightness of roof coverings in rain conditions. Putting this into practice requires thoughtful engineering solution and rational arrangement of all elements and parts of the roof.

The regulatory requirements of the German Roofing Association concern primarily the professional production of valley grooves using sheet metal technology. In practice, the boards or bars that form the load-bearing structure of the valley are laid only on top of the under-roof waterproofing. In this case, the places where the bars are fastened with nails are located in the place where water flows over the surface of the film. Often the counter-lattice runs straight in the direction load-bearing structure valleys (Fig. 6). When using such methods for making valleys, problems arose related to getting the thermal insulation layer and even rafters wet, which could in some cases lead to a decrease in the load-bearing capacity of the roof structure.

Rice. 6 Errors when installing counter-lattice bars in the valley

Sometimes even in the instructions of manufacturers of roofing materials or under-roofing films (!) one can find, to put it mildly, controversial solutions for installing waterproofing on valleys (Fig. 7). Of course, experienced craftsmen will carry out work based on common sense, but most of roofers can repeat such structures that have a small margin of safety.		Rice. 7. Gross mistake: the sheathing is secured with nails along the drainage groove along the edges of the valley flooring. Moisture penetration under the waterproofing is guaranteed
The most reliable option is in which the entire valley structure is covered with a waterproofing layer on top. This can be achieved without much difficulty if you lay the rolled waterproofing material to its full width in the center and parallel to the valley line (Fig. 8). In this case, the width of the longitudinal layer waterproofing membrane extending onto each adjacent slope will be equal to 75 cm. Roofers will be able to hermetically connect (glue) this layer of valley waterproofing with the membrane rolls laid on the slopes without any problems. Some roofers still use bitumen on valleys. roll materials- this can only be justified on roofs with double-layer ventilation. On fully insulated roofs, laying vapor-proof material can create problems for the normal ventilation of the insulation and truss structure in the valley area, and the valley is one of the most difficult and risky places on the roof.		Rice. 8. Professional installation of waterproofing in the valley. DORKEN schemes

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 systems 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 of this element is of great importance, since installation errors can lead to leaks, damage to the insulation and additional repair costs.

Valley design diagram

The valley is one of the most important and complex elements of the roof structure. The interface line 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 design features roof, as well as 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 a 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, the upper part of the valley is not used. To improve the waterproofing properties of its lower valley upper shelves

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:

1. The design of the rafter system, which serves as the basis for installing the valley strips, depends on the intended type of 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.
2. 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
3. , which are mounted along the joints of the roofing covering in increments of 10 cm. Lathing with additional elements
4. . 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

1. Installation of the valley is carried out 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.

2. The drip cap is made of the same material as the main roofing covering On both sides on the bone rafter leg The lower ends of the bars must be sawed flush with the eaves overhang.
3. 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 staples 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.

4. 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 secured from 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

5. 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.
6. On top of the waterproofing, valley board bars are packed, which form an 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

7. 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.
8. 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

9. 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

10. 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.
11. 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. In the presence of drainage system a plastic overhang apron is installed. Its task is to prevent water and snow from getting into the ventilation gap between the tiles and the waterproofing.

    To counteract snow loads, a thick sheathing is installed under the lower valley strip

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:

1. 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.
2. 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.

3. 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

4. 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 on 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 wooden sheathing using clamps fixed with nails or self-tapping screws. The upper element of the valley must be screwed with self-tapping screws to the metal tile. It should be noted 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 attention Special attention on the quality of the sheathing. It is recommended to install the lower gutter on a continuous sheathing, the width of which should be no less than the width of 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 with the even laying of the 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.

1. A waterproofing layer is installed along the entire length of the base. The best option To strengthen the gutter nodes, use a valley carpet. This protective covering 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.
2. The waterproofing material is fixed using special stickers or nails. If the carpet is nailed, the distance between them should be about 20 cm.
3. The lower valley elements, roofing, seals and decorative parts are installed.

To strengthen the valley nodes, instead of 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:

1. 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.

2. A tile spike that hits the valley is knocked off or cut off so that it does not crack at the groove.
3. 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.
4. A hole for the self-tapping screw is first drilled in the trimmed tile so that it does not fall into the groove.
5. 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

6. 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

7. The prepared trimmed tiles are laid in place and fixed with a self-tapping screw. Roof tiles from top row moves down and presses the trimmed element.
8. 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.
9. The upper cut of the outermost ridge tile is covered with a special tape for junctions. The valley installation is complete.

   Corrugated tape is 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:

1. Attempting to cut tiles directly at the valley using a grinder. This often leads to damage to the already secured groove. Moreover, it is very difficult to achieve straight line cut along the entire length of the gutter, 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

2. Fastening the groove with nails along the entire length.
3. 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 rather than flow down.
4. 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.
5. 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, installation of this roofing element It is better to entrust it to experienced specialists. In this case, errors that lead to serious problems will be eliminated.