Waterproofing roofs

Waterproofing membranes can be divided into three main families: breathable, vapor retardant and vapor barrier.

Some characteristics are common to all families:

• guarantee waterproofing;

• they are sold in rolls weighing 9 kg / each. (they are therefore very light and easily transportable on site without the aid of winches or cranes) and cover 75 m2 of surface (the roll is 1.5 meters high and 50 meters long);

• they are laid simply by unrolling the roll and can be cut with a normal cutter; installation times are extremely low (just a few minutes are enough for the roof of a single-family house).
  
  

What are the differences:

• the transpiring ones allow water vapor to migrate to the outside (they are particularly suitable for the wooden roof), not allowing condensation to form;

• the vapor brake allows a minimum migration of water vapor;

• the vapor barrier does not allow the passage of water vapor to the overlying layers.
  

Then they still differ from each other in having or not a layer consisting of a self-sealing film that vulcanizes around the nail or staple used to fix them to the structure. There are some with one or two adhesive bands that allow you to firmly fix the waterproofing layer that precedes with the one that follows in the overlapping area and prevent infiltrations even in areas where the climatic conditions are among the most prohibitive.

For complete information on installing BMI waterproofing membranes, consult the Installation Manual.

To best design your roof system you can get help from our local experts with BMI Expert.

Protection, comfort and resistance and durability are the main advantages the roof acquires thanks to membranes and insulating panels.

To waterproof the pitched roof, bituminous or synthetic membranes must be used.
The membranes are specific additional mandatory protection as they protect the building from any water infiltration that can cause major aesthetic damage (stains, mold) and functional damage (damage to the structure).

They are also mandatory in cases of pitch slopes of less than 30% or homes located in areas subject to adverse climatic conditions. In the case of roofs built on discontinuous structures, they also avoid the entry of dust and condensation.

The infiltrations could occur as a result of any accidental breakage of the roof covering (incorrect foot traffic during roof maintenance), the movement of some roofing elements (strong gusts of wind), or sudden and violent atmospheric events (strong summer storms, air, etc.).

The reflective membranes have the characteristic of reflecting 55% of the heat rays that are transmitted by irradiation through electromagnetic waves that propagate from the hottest to the coldest point so that, for example, inside an attic there is up to at 4 ° C less when using a membrane with the reflective side facing up.

The surface of the tile reaches a surface temperature close to 80 ° C when the air temperature is about 30 ° C; this heat tries to penetrate inside the building: if we place a reflective membrane in the under-tile, we obtain the reflection of the heat rays upwards (ie towards the outside) with the thermal benefits listed. BMI offers various types of membranes with the Premium and Standard lines that increase the efficiency of the insulation during the summer.

The BMI product range is completed with connection tiles, created specifically to connect the outlet elements in a safe and definitive way, and with a particular tape, Wakaflex®, ideal for sealing the most difficult points of the roof.

The connecting tile is a tile with an elliptical hole in the center with raised edges; the 13 x 16 cm hole allows the outlet of the vent and ventilation pipes of bathrooms and kitchens providing a functional and aesthetic connection; to close the hole, you can use copper or PVC vents, an antenna holder cap or the chimney pot. The jointed PVC joint, element joining the tile with the upper accessory, guarantees air and water tightness.

The waterproofing of the connection points is thus guaranteed by standard, prefabricated modules that can be used with any type of tile. Wakaflex® tape is an adhesive band designed to make any type of joint and connection for walls, roofs and chimneys, adaptable to all situations and tile shapes.