Look how this roof has rapidly deteriorated to a poor condition. Asphalt flat roofing must either have a coat of solar-reflective paint or a layer of fine stones over it for protection from the sun’s UV rays and the heat
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.
- New, more efficient roofing products have been developed.
Due to the low demand for asphalt roofing, skilled workers are harder to find. Asphalt roofs are often badly installed and are in need of attention well before their time. We work on asphalt roofs older than a hundred years, that have needed very little maintenance, yet more frequently we’re replacing new asphalt roofs, laid only 3 – 5 years ago!
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 (SBS) 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.