Waterproofing for metal tile: choice and installation

The choice of roofing often decides how much the roof will be effective in performing its primary tasks. The protective properties of the structure are also influenced by the rafter base, which performs the supporting function. However, even in the case of a qualitative construction of the roofing "pie", there remains the risk of its natural destruction under the influence of weather phenomena. One of the most serious enemies for wood, metal and concrete is moisture. To protect roof elements and the supporting structure from negative influences, use insulation coatings. Especially this material is necessary in the case of metal decking. In particular, waterproofing for metal roofing can be an optimal protective solution. It will help to create the necessary barrier before precipitation, and also will increase the effectiveness of thermal insulation material, if that is also provided in the under-roof space.

Do you need insulation for metal roofing?

Almost all the metal building materials that are involved in the formation of external structures, lining and coatings, today receive anti-corrosion protection. But even modern methods of galvanizing can not guarantee the protection of surfaces from rust in conditions of close and constant contact with water. Accordingly, the question of whether a waterproofing is necessary under the metal tile presupposes an obvious answer - it is necessary as a means of protection against the development of corrosive processes.

And it's not just that the rear layer will protect the structure from rain and penetration of thawed water. A qualitatively arranged insulation coating also prevents the appearance of condensate, which without a suitable barrier can become permanent. And this applies only to the functions aimed at protecting the inside of the roofing. In addition, waterproofing under the metal tile does not allow contact with the moisture of structures located in the under-roof space. The most moisture-sensitive material in this niche is a heater, which in any case requires protection from the same condensate.

What is a roofing waterproofing?

Most often this cloth, made of elastic plastic and composite materials with elements of fiber. It is calculated to create an effective barrier to moisture in any form. Typically, the basis of waterproofing is polyethylene fiber. A functional feature of this material is the removal of moisture through special pores. That is, the material does not accumulate water or steam, but immediately removes it through the ventilation duct, which must also be provided in the construction of the under-roof space. It is important to note and other properties, which has a waterproofing on the roof for metal in the best designs. In the list of basic performance qualities, frost resistance, strength, durability and the ability to withstand chemical influences can be introduced. Far from always accumulating liquid on the roof is safe in terms of chemical reactions, so this nuance should be considered when choosing an insulation layer.

Varieties of material

The simplest solution is a waterproofing film, which includes a substrate and a polyethylene coating that forms a barrier. In fact, this material only creates a wall in front of moisture, but the liquid will not go anywhere until it dries. A more modern look is a membrane superdiffusion film that collects moisture, and then withdraws it through the pores. It is important to note that such coatings are one- and two-circuit. That is, they provide their function on one or two sides. An improved modification of membrane coatings is an anticondensate film. This is the best waterproofing for metal roofing, because thanks to the pile surface it implements an intensive drainage of moisture, while also providing the ventilation function. However, the cost of such a film is much higher.

How to choose the best insulation

The device of highly effective membrane films does not always justify itself. This choice should be done only in cases where the house is located in a region with frequent precipitation. The merits of this material include mechanical properties with frost resistance, but not in each roof, these qualities will be paramount. As for the simplest models of film insulators, they can be used in cases where the function of moisture protection effectively implements the substrate, the heater itself and the roof. In the question of how to choose a waterproofing under the metal tile, aspects that are not related to the waterproof are also important. For example, the presence of a strong base in the film structure. The most reliable option in this respect is a coating in which one side has a foil surface. In this case, a sufficiently high function of mechanical protection against physical impacts will be provided.

Preparing for installation work

At the time of laying the waterproofing, the roofing system should be formed, as well as the components of the roof's engineering infrastructure. In particular, the withdrawal of the ventilation path, the cornice, gutters and other components of the fittings should be prepared. If the waterproofing is laid under the metal roofing of the cold roof, special attention should be paid to the substrate. It depends on how warm the house will be, and moisture protection, in turn, will protect the floor from condensation. Before laying, you also need to calculate the material by the rafter system. It is desirable that as few as possible of the docking areas are formed, this will increase the leaktightness and strength of the coating.

Substrate device

As a rule, the substrate creates the basis for the whole roofing cake, starting from the beams of the rafter system. Today the market presents a lot of composite and natural materials to create such a flooring, but it makes sense to use a traditional roofing felt. It is characterized by the optimum qualities of heat and waterproofing, and provided that the quality of the special insulators in the upper layers is high, its presence will be more than sufficient. If you plan to lay the waterproofing under the metal roof on the roof with a cold attic or attic, the covering of the roofing material can be made on two layers. Fixing of the flooring is made with the help of roofing hardware in the form of carnations with a large bonnet. Indents are made in steps of 50-60 cm, and if necessary, the joints can be treated with wear-resistant sealants.

Installation process

There are two approaches in the installation of waterproofing. The first involves laying the cover directly on the insulation layer. This option is less reliable, but it justifies itself, if there are no high requirements for the protection of the roof. More common scheme involves the installation of waterproofing under the metal with the organization of the system of two crates. The first layer of boards and lag is mounted on a substrate, where a heat insulator can also be located. Further on the construction is laid water repellent film. To fix a waterproofing in this case it is not necessary, if the firm clamp by boards was provided. On top of the cover, the second part of the crate is laid, which fixes the film. Again, if there is not enough clamping after laying the wooden elements, then you can insure the insulation with a construction stapler.

Additional insulation

The most reliable insulation protection is formed by three types of coating. This is a heater, steam and waterproofing, which represents the uppermost layer on the crate. Some models of water repellent films can perform all three protection functions, but still this option will play configurations with separate decks. For the implementation of this scheme, after the construction of the roofing material and up to the time of fastening the crate, two layers are laid - heat and vapor insulation. They can be represented by foil, natural and synthetic materials. By the way, the vapor barrier looks outwardly as a membrane waterproofing for metal roofing, but its thickness is less. The thickest layer can become a heater, represented by mineral wool or expanded clay.

Conclusion

The presence of the waterproofing in the structure of the roofing does not mean that the other components of the structure will be guaranteed to be protected from the effects of moisture. Much also depends on how tightly the basic flooring was formed. Usually the waterproofing of the roof under the metal tile is arranged not close to the coating, but with the preservation of the ventilation gap. If the tile layer will have serious defects or large technical gaps, there is a risk that even a high-quality thick insulator can not cope with its task. Therefore, in the provision of moisture protection, much depends on the reliability of the upper roof covering, which should be checked regularly for leaks and during operation.