The choice of roofing often decides how effective the roof will be in fulfilling its primary tasks. The protective properties of the structure are also affected by the rafter base, which performs the supporting function. However, even in the case of a high-quality construction of the roofing “cake,” 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 the elements of the roof and the supporting structure from negative influences, use insulating coatings. This material is especially necessary in the case of metal flooring. In particular, waterproofing under a metal tile can be an optimal protective solution. It will help create the necessary barrier to precipitation, as well as increase the efficiency of the heat-insulating material, if it is also provided for in the under-roof space.
Is insulation necessary for a metal tile?
Almost all metal building materials that are involved in the formation of external structures, cladding and coatings, today receive corrosion protection. But even modern methods of galvanizing are not able to guarantee the protection of surfaces from rust in conditions of close and constant contact with water. Accordingly, the question of whether waterproofing is necessary under a metal tile suggests an obvious answer - it is necessary as a means of protection against the development of corrosive processes.
And the point is not only that the rear layer will protect the structure from rain and the penetration of melt water. A well-constructed insulation coating also prevents the formation of condensation, which can become permanent without an appropriate barrier. And this applies only to functions aimed at protecting the inside of the roofing. In addition, waterproofing under a metal tile does not allow contact with moisture of structures located in the under-roof space. The most sensitive material to moisture in this niche will be insulation, which in any case requires protection from the same condensate.
What is a roof waterproofing?
Most often, this canvas is made of elastic plastic and composite materials with fiber elements. It is designed to create an effective barrier to moisture in any form. Typically, the basis of waterproofing is polyethylene fiber. The functional feature of this material is the removal of moisture through special pores. That is, the material does not accumulate water or steam in itself, but immediately discharges it through the ventilation duct, which should also be provided in the design of the under-roof space. It is important to note other properties that waterproofing on the roof under the metal tile in the best versions has. The list of basic performance can include frost resistance, strength, durability and ability to withstand chemical influences. The liquid that is not always accumulated on the roof is safe in terms of chemical reactions, therefore this nuance should be taken into account when choosing an insulating 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 does not go anywhere until it dries. A more modern look is the membrane superdiffusion film, which collects moisture, and then removes it through the pores. It is important to note that such coatings are single and double circuit. That is, they provide their function from one or two sides. An improved modification of membrane coatings is an anti-condensation film. This is the optimal waterproofing for metal tiles, because thanks to the fleecy surface, it implements intensive moisture removal, while at the same time providing a ventilation function. However, the cost of such a film is much higher.
How to choose the best insulation
The device of high-performance membrane films is far from always justifying itself. This choice should be made only if the house is located in a region with frequent rainfall. The advantages of this material include mechanical properties with frost resistance, but not in every roof these qualities will be paramount. As for the simplest models of film insulators, they can be used in cases where the moisture protection functions are effectively implemented by the substrate, the insulation itself and the roof. In the question of how to choose a waterproofing for a metal tile, aspects that are not related to moisture protection are also important. For example, the presence in the structure of the film of a solid base. The most reliable option in this regard will be a coating in which one of the sides has a foil surface. In this case, a sufficiently high function of mechanical protection from physical influences will be provided.
Preparing for installation work
At the time of installation of the waterproofing, a rafter system must be formed, as well as components of the engineering infrastructure of the roof. In particular, the outlet of the ventilation passage, the cornice, gutters and other accessories of the fittings should be prepared. If waterproofing is laid under the cold roof metal tile, 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 flooring from condensation. Before laying, it is also required to calculate the material according to the rafter system. It is desirable that as few joint areas as possible are formed - this will increase the tightness and strength of the coating.
Substrate device
As a rule, the substrate creates the basis for the entire roofing cake, starting from the beams of the rafter system. Today on the market there are a lot of composite and natural materials for creating such a flooring, but it makes sense to use a traditional roofing material. It is distinguished by the optimal qualities of heat and waterproofing, and if the high-quality installation of special insulators in the upper layers of its presence is more than enough. If you plan to lay waterproofing under a metal roof tile with a cold attic or attic, a roofing material coating can be done in two layers. The flooring is fixed with the help of roofing hardware in the form of carnations with a large hat. Indentation is done in increments of 50-60 cm, and sections of the joints, if necessary, can be treated with wear-resistant sealants.
Installation process
There are two approaches to installing waterproofing. The first involves laying the coating directly on the insulation layer. This option is less reliable, but it pays off if there are no high requirements for roof protection. A more common scheme involves the installation of waterproofing under a metal tile with the organization of a system of two crates. The first layer of boards and lag is mounted on a substrate, where a heat insulator can also be located. Next, a water-repellent film is laid on the structure. In this case, it is not necessary to fix the waterproofing if a tight clip was provided with the boards. On top of the coating, the second part of the crate is laid, which fixes the film. Again, if after laying the wooden elements a sufficient clamp was not ensured, then the insulation sheet can be secured with the help of a construction stapler.
Additional insulation
The most reliable insulation protection is formed by three types of coating. This is a heater, vapor and waterproofing, which represents the topmost layer on the crate. Some models of water-repellent films can fulfill all three protection functions, but still this option will lose configurations with separate decks. To implement this scheme, after the installation of roofing material and until the fixing of the crate, two layers are laid - heat and vapor barrier. They can be represented by foil, natural and synthetic materials. By the way, the vapor barrier looks outwardly like a membrane waterproofing under a metal tile, but its thickness is less. The thickest layer may be insulation, represented by mineral wool or expanded clay crumb.
Conclusion
The presence of waterproofing in the structure of the roofing does not mean that other components of the structure will be guaranteed to be protected from moisture. Much also depends on how hermetically formed the main flooring. Typically, waterproofing a roof under a metal tile is arranged not close to the coating, but with the preservation of the ventilation gap. If the tile layer has serious defects or large technical gaps, then there is a risk that even a high-quality thick insulator will not cope with its task. Therefore, in ensuring moisture protection, much depends on the reliability of the upper roofing, which should be regularly checked for leaks and during operation.