Asphalt roofs are the roofing of choice for a lot of homeowners. To replace such roofs, roofing companies need to strip the old shingles from the roof and put up new ones. In several areas, tar paper and old asphalt shingles are recycled into products like paving material. However, they are also dumped in landfills or buried in non-designated areas in other places. Asphalt is not biodegradable either.
Roofing manufacturers say that the three-tab shingles that are commonly used have life spans of 15, 20, 25 and 30 years depending on their grade, which is then put on their packaging. However, the lifespan of a shingle depends on several items which are outside the control of the shingle manufacturers: sea air, weather, sun, trees, etc. The average asphalt shingle is composed of paper and wood fibres in a petroleum product and is susceptible to airborne solvents. The stone surface wears away, and the exposed shingle starts curling and becomes brittle. However, the more expensive ones have a fibreglass composition which makes them last longer. Environmental studies have proven that asphalt shingles in a landfill take anywhere between 100 to 300 years to decompose.
This is where metal roofing comes into play. There is nothing inherently toxic about metal, and they are longer lasting. However, different metals have different properties that make them suitable for roofing.
Aluminium is increasingly being used as a roofing material nowadays. Its weight, which used to be a detriment, is now seen as a plus point because of easy new installation techniques and wind-resistant design.
- Standing Seam Aluminium Roofs: These are of traditional design but can now be manufactured from spools of aluminium, much like seamless gutter machines, so that there are no breaks to seal.
- Shakes: Other than the traditional standing seam lengths, roofs are now being manufactured in shakes that look like wood shingles or tile. These aluminium shakes interlock to form a complete roofing system that can withstand winds as fast as 200 kmph.
Steel roofing actually came on the market as competition to aluminium. Steel was a good, lightweight material and cheaper than a lot of other metals, but the paint on them tended to peel off more easily, and corrosion was a major problem, especially in salt-rich air. Today, steel roofs are coated with a PVC polymer or a metal alloy such as zinc or aluminium and just like it, the steel product comes in tile form too.
If money is not an issue, then copper is the best roofing material. After all, there are thousands of cathedrals in Europe and government buildings in Canada that have copper roofs that can withstand the elements for centuries. Copper does not have to be painted either because it oxidizes to this beautiful dull greenish-blue colour which is in itself quite beautiful to see.