How to waterproof the roof

Roof waterproofing Table of contents:

  • 1 Waterproofing functions
  • 2 Insulation device
  • 3 videos

Any roofing is, as you know, pie of several layers, each of which is intended for their goals. These layers usually include:

  • direct coverage;
  • waterproofing layers;
  • natural ventilation system of the roof.

Waterproofing Functions

Roof waterproofing functionsWaterproofing Functions the roof

The need for waterproofing is explained by the fact that the roof during its long-term use is exposed to many destructive factors. If moisture gets under the roof the insulation begins to rot and collapse, which in the future may damage to supporting wooden structures.

In order to waterproof the roof, you need, first of all, to know that it not only protects the structure from moisture penetration, but also performs a number of auxiliary functions:

  • prevents the entry of natural rainfall under the roof;
  • serves as protection against condensation;
  • included in the ventilation system.

Condensate is known to form due to the temperature difference under roofing and above it and can accumulate on the surface of the insulation or other structural elements. Special ventilation circuit (which includes waterproofing layer) prevents the occurrence of condensate.

Consider the options for forming a protective layer using a variety of waterproofing materials.

Isolation device

Insulation Device

For the preparation of waterproofing, films of various types are used, which are usually divided into “non-breathing” and “breathing”. So called “breathing” films are divided in turn into simply diffusion and superdiffusion. Let us first consider the second type of films, which made of synthetic non-woven materials and work on the principle of a one-sided membrane that lets moisture out and not letting them in.

This type of waterproofing is laid directly on the insulation, which allows you to create one ventilation circuit. Roofing it is thinner and lighter; Moreover, such a film is capable of provide good wind protection and significantly reduces heat loss through the roof.

Another variety of “breathing” materials are diffusion films made of polypropylene or polyethylene. They have special perforations that let steam through freely, but effectively retaining external moisture.

Diffusion films should be laid on the insulation and roof covering with a small gap, since they steam transmittance slightly lower than membranes.

Waterproofing schemeWaterproofing scheme

Films from the “non-breathing” category are mainly made from polypropylene (polyethylene). When using them you have to create a double-circuit ventilation system under the roof. Such films it is convenient to use when the cross section of the rafters is slightly higher than normal. IN in this case, between the insulation layer and the upper cut of the rafters a decent gap remains.

Another kind of “non-breathing” materials are as follows called anti-condensation films, the inner layer of which holds drops of condensate, preventing them from rolling down. With In time, all condensate accumulated on them dries. At using such a film you will need to make a couple small gaps of about 8-10 cm (for ordinary film – about 5 cm).

The outcome of the consideration of the question “how to make waterproofing roof “is a reminder that it must be arranged throughout the roof, not excluding pediment and eaves overhangs. The lower section of the canvas should be displayed beyond the edge of the cornice, thereby ensuring its adjacency close to the walls and ventilation pipes.


The procedure for laying roof waterproofing is presented in the following Stock Footage:

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