Waterproofing films for roofing

Modern building technologies offer a wide selection of roof repair in private buildings. They differ in quality, material, method of installation and, of course, price. When repairing a roof, an important point is proper waterproofing. One of the popular and affordable methods is roofing waterproofing with a film.

A man puts a waterproofing film for the roof


  • Advantages and disadvantages
  • Varieties and properties
  • Vapor barrier films
  • Necessary materials and tools
  • How to do it yourself?
  • The cost of film materials
  • Tips & Tricks

It is necessary to protect insulation materials and wooden parts of the roof from moisture, precipitation, condensate. An important role is played by protection from drafts and wind of a premises.

A large amount of precipitation without waterproofing can easily penetrate the building structures made of wood, which will lead to their rapid decay. Also harmful moisture affects the insulation, which significantly reduces its thermal insulation.

When passing through the attic of the heating pipes of the hot water supply systems, it significantly increases the condensation, and, therefore, the need for roof waterproofing.

So from properly selected roofing materials, their installation and installation depends on the service life of the entire roof.

Film waterproofing is necessarily used for roofing pitched roofs with coatings that do not form a continuous cover.

Such materials include:

  • slate;
  • metal roofing;
  • all types of tiles;

Since these roofing materials have an inconsistent structure, in stormy weather conditions, strong winds or heavy rains, there is the possibility of rainfall entering under the roof. Therefore, waterproofing with a film has an important protective function.

When installing flat or pitched roofs, a waterproofing film with the function vapor barrier, which protects the insulation from water vapor coming from the interior.

Advantages and disadvantages

Roofing film waterproofing has several advantages compared with other waterproofing materials.

The main ones are:

  1. Durable, resistant to stretching and tearing.
  2. It has an anti-condensation layer.
  3. Waterproof.
  4. Able to increase heat transfer.
  5. Possible for use in saunas and baths.
  6. Wide temperature range for use.
  7. Fairly low cost.

Professional builders do not distinguish obvious or significant shortcomings in film waterproofing and recommend it as the most affordable and convenient for non-professional use in private roofing buildings.

Varieties and properties

For polyethylene roofing films, an additional reinforcing mesh is always used, a fabric that gives additional strength to the entire structure.

The most popular materials for roof waterproofing are film-type materials.

The following types of films are distinguished:

  1. Diffusion membranes.
  2. Polypropylene films.
  3. Roofing polyethylene.

Membrane films, called "breathing" for their special microstructure of membranes, which protect against external moisture penetration and remove the vapor that creates condensate. The advantages of this type are that the film is laid directly on the insulating material, dispensing with the ventilation gap.

Exists foil vapor barrier membrane with waterproofing, which is very common with roofing saunas, baths, which allows you to save and protect the insulation from increased vaporization, as well as for additional thermal insulation inside premises.


  1. Perforated film.
  2. Non-perforated.

Reinforced polypropylene films differ from previous types of films with the greatest strength. Also have high resistance to ultraviolet radiation. They are produced both with and without an anti-condensation layer.

The anti-condensation layer, consisting of cellulose and viscose fiber, can absorb a huge amount of released moisture, while not emitting a single drop of condensate. After eliminating large vapor evaporation, the layer dries quickly, retaining all its properties.

There is also a conditional classification of films for waterproofing and vapor barrier films. It is conditional, because often professional builders use and interchange them with each other.

Vapor barrier films

Vapor barrier roofing filmEvaporation, water vapor, as is known from the laws of physics, always rises up, where it gathers under the roof. There is also a heater, which should always be dry.

Therefore, when waterproofing, it is necessary to put between the heat-insulating layer and the ceiling, a special vapor barrier film.

Such a film is characterized by a high level of vapor impermeability, which directly depends on the density of the material, and tensile strength. The continuity of the film provides additional protection against leakage and collapse in the event of a collapse of the roof structure.

At installation of vapor barrier film it is necessary to take into account the high permeability of water vapor. Therefore, an important point is the careful sealing of the joints, in contact with the film walls, pipes and other building structures.

Most often, construction professionals use double-sided tape from butyl rubber.

Necessary materials and tools

After completing the basic preparatory roofing, you can proceed to waterproofing. But for this you need ready installation of the rafter system, cornice and frontal boards are installed, and hooks for a drainpipe have already been installed.

Having decided on the material for waterproofing the roof, you should prepare all the tools necessary for the job.

For this you need:

  1. Wide double-sided rubber tape.
  2. To fasten the insulation to the rafters, a powerful construction stapler is needed.
  3. Nails with a large hat for a firm hold, preferably galvanized or stainless steel.
  4. Hammer.

How to do it yourself?

Installation of waterproofing on the roofInstallation of roof waterproofing can be done independently. To do this, first, on top of the insulation layer, horizontally lay and cut the pieces of film necessary along the length. Given the overlap, which depends on the slope of the roof, most often it is 15 cm. Fix the canvas on the rafters using a construction stapler.

An obligatory moment is to glue the place of overlap with a mounting tape. On top of this layer of film lay wooden slats that are mounted on nails. To increase their service life, it is recommended to treat with an antiseptic. Particular attention should be paid to fixing the joints of the film.

Then a control rail of 4-5 cm is laid. It provides the formation of a space between the waterproofing film and the roofing material. This space is necessary for free air circulation.

The final step is the installation of a conrocrate, on which roofing material is then superimposed and fixed.

The cost of film materials

Roofing waterproofing filmThe modern market offers a fairly wide selection of waterproofing materials, the cost of which depends on the quality, type and characteristics.

For example, for ease of installation, there are films with a sticky layer at the edges, however, and they are already more expensive than usual. Membrane films are the most expensive of this category.

Of course, the price also depends on the manufacturer. Domestic, as a rule, is cheaper than foreign.

It should also be borne in mind that the film material is produced in rolls of various widths and densities, on which not only the place and field of application, but also the price depends.

The cheapest, affordable, convenient and high-quality is polyethylene film material. Most often it is used for private housing construction and carry out installation work independently. The combination of ease of installation and accessibility make it the most common.

Tips & Tricks

House under construction

The modern roof has a multicomponent complex device. It provides not only protection of the house from rainfall, but also ensures the safety of the temperature regime.

Professionals recommend:

  1. Roofing film waterproofing is necessary for slate roofs, metal tile.
  2. Choose waterproofing films with anti-condensation layer.
  3. A high-quality film should be: strong, waterproof, elastic, resistant to high and low temperatures.

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