Films Under Roof Tile – How To Assess Their Quality And Performance


Films under the tile are one of the most used elements under the roof in recent years. Likewise, its performance and durability have been improving and there is, nowadays, a wide variety of films of this type on the market. In addition, many architects, installers and distributors know which film is most suitable for each project.


The most common are known as waterproof and breathable membranes and depending on their degree of resistance to the passage of water vapor, coefficient SD, they are known as vapor barrier. There is no official scale, but it is usually indicated that after 100 meters of resistance to the passage of water vapor, SD 100, we can start talking about a vapor barrier. Conventional films are less than 1m. Whether this value is higher or lower is not an indication of higher or lower quality as the key is where to place the film on the roof assembly to prevent condensation. Visit the website here to consult roofing experts about films under roof tiles.

It has two main benefits:

The first is unknown by most users, and is to prevent the wind from cooling the insulation, for this it is essential that the overlaps between films are well sealed and with the recommended tapes for this purpose, although there are films that include self-adhesive strips, highly appreciated by installers, allowing them to save valuable installation time. One of the factors to take into account is the tightness or resistance to air penetration of the films. Without a doubt, this big unknown makes the difference when it comes to maintaining and achieving design insulation performance.

Ensuring insulation for the roof becomes very important especially during the winter season when the snow that settles on the roof can easily melt, causing it to flow down into the gutters and in turn causing ice dams. While regular gutter cleaning with help from the likes of Clean Pro Gutter Cleaning FISHERS or elsewhere can also help with this, it’s important that parts of the attic and roofing are also insulated well enough for the warm air not to penetrate the tiles.

The second mission is to protect against possible water ingress due to, for example, strong gusts of wind, snow, condensation under roof tiles, etc. Protecting the lowest levels of humidity, here the characteristic that best allows us to compare the films is how the impermeability is measured under the premise of the water column test in mm.