Asphalt Roofing
The damaging effects of sunlight on quite new asphalt roofing.
This roof has rapidly deteriorated to a poor condition.
Asphalt flat roofing must either have a coat of solar-reflective paint
or a layer fine stones for protection.
Asphalt is known as the king of flat roofing materials. Asphalt roofs have stood the test of time for centuries. However we are seeing a sharp decline in Asphalt roofing nowadays. Here's why:
- High labour costs to install asphalt roofing.
- Asphalt raw material is expensive.
- Asphalt roofing is heavy - the supporting structure must be super strong.
- Asphalt roofing needs a coat of solar-reflective paint or layer of stones, renewable every 2-3 years.
Asphalt Roofing Facts
Mastic asphalt is a blended bitumen based product, made either from the bitumen produced by distillation of crude oil, or from lake asphalt, a naturally occurring blend of asphalt containing 36% by weight of finely divided clay. The bitumen is blended with limestone powder and fine limestone aggregate to produce mastic asphalt roofing.
The effect of the finely divided clay particles within lake asphalt confers better laying characteristics and enhanced thermal properties. This is particularly beneficial when the mastic asphalt roofing will be exposed to wide temperature variations, as in warm roof construction.
Mastic asphalt roofing is normally delivered to site as blocks for melting on site prior to laying. Laid mastic asphalt is brittle when cold, but softens in hot weather. Polymer-modified mastic asphalts, usually containing styrene butadiene styrene block copolymers, are more durable and have greater flexibility and stretch at low temperatures. This allows for greater building movement and better resistance to thermal variation.
Where mastic asphalt roofing is exposed to foot or vehicle access, then paving-grade mastic asphalt should be applied as a wearing layer over the standard asphalt roofing grade material.