Mineral fillers can improve the performance of the roofing material by:
- providing flame-retardancy
- supporting the IR reflection in order to keep the temperature of the underlying room/building low, thereby reducing the energy consumption and costs.
- providing resistance towards UV and thereby improving the longevity of roof structure
Bitumen roofing felt has the the following layered structure:
Sibelco’s minerals can be used to add following characteristics:
- Flame retardancy (ATH, Colemanite)
- Anti stick (Silica) by providing enough surface roughness
- Bitumen is a residue from crude oil destillation containing a complex mix of asphaltenes, aliphatic hydrocarbons, polar & naphtenic aromatics. Bitumen roofing felt’s main properties are depending on the mix of the constituents of the bitumen and the fillers used.
The mix of the constituents also determines the flammability of the bitumen:
- For roofing applications following characteristics are targeted
- SOFTENING POINT (Ring and ball): 50 – 120 ºC
- PENETRATION DEPTH @ 25 ºC (100/5): 15 – 75 (0.1 mm)
- FLASH POINT (Open cup): 225 – 260 ºC
- Bituminous roofing systems can be modified by the addition of polymers, generally two types:
- With following compositions types:
- SBS (Styrene-Butadiene-Styrene) modified (see green square), or
- APP (Atactic-PP) modified (see green square)
To make the roofing system flameretardant it is recommended to use the coarser grades Portaflame SG 63 and Portaflame SG200 (with the former being a little more effective) or Colemanite C75 or combinations herewith.