Bitumen felt is a roofing material produced by saturating cardboard with liquid bitumen. With this material a dressing compound for the front surface is not required.
Bitumen felt is produced in 1000, 1025 and 1050 mm rolls. The total area of one roll can reach 40 m2.
This roofing material has the following specifications:
- 20% max absorption of water by weight;
- 220… 320 N tension breaking strength.
Bitumen felt is predominantly used as the lower or middle layer of roof cover and as a vapour barrier in structures.
The main difference between ruberoid and bitumen felt is the number of layers. The production technique is similar: bitumen felt is saturated with low-melting bitumen, but then both sides are coated with a composition made of high melting bitumen filled with mineral powder.
The front surface of ruberoid is covered with protective or decorative dressing compound consisting of mineral materials. The underside is dusted with fine limestone or talcum. This is required to avoid adhesion inside the roll.
The main disadvantages of ruberoid as a roofing material are its low lifespan and decay.
Short service life was the reason why application of ruberoid was seriously limited and prohibited entirely in some countries. Now this material is mostly used for roofing of temporary buildings.
Bicrost is a roofing material produced by double application of air blown bitumen and filler on polyether or glass base. Consumption of the binder in this case is 3.5-4 kg/m2.
The front surface is protected by coarse and flaky, dusty and fine dressing compounds. The base can be polyester, glass-fibre mat or glass cloth.
Bicrost is used for roofing of buildings and waterproofing of structural elements. Lifespan of bicrost roofing is 10 years on average.