What's in a Roof?2010-05-26 11:53:00
Roofs generally protect us from rain, heat, sunlight, cold and wind, but there are many methods that can be employed when designing a roof, and many factors to take into account, such as: what materials should be used, how durable the will roof be, and is the roof helping the building to be environmentally friendly?
Roofs range in use of materials from banana leaves and straw to metal and terracotta, but one needs to be practical when choosing what materials to be used. For example, larger buildings with thatch-type roofs are impractical as they require regular maintenance, which, while aesthetically pleasing, can work out to be very expensive in the long run.
For smaller buildings thatch can be ideal as it serves as insulation as well, whereas buildings that make use of other materials generally have a ceiling installed under the structural member of the roof, to guard against cold, noise and dirt.
Since the primary function of a roof is to keep out water, drainage is a vital factor in the design and construction process. Commercial buildings – often with flat roofs – need to have a highly impermeable outer layer and proper drainage systems to avoid any damage or inconvenience.
Areas with high rainfall and snow are usually characterised by buildings with steep roofs, while areas with less precipitation generally have roofs with a lower pitch.
In built-up urban areas it's not uncommon to find large buildings with gardens on their roofs, which can actually help reduce the overall heat absorption of the building – which in turn will reduce energy consumption.
According to a study at the National Research Council of Canada, if roof gardens were widely adopted the urban heat island could be reduced, which would decrease smog episodes and further reduce energy consumption.
Solar panelling is becoming increasingly popular, and in a country with a climate like South Africa's it makes sense to utilize this method as it can significantly lower electricity costs within the building.
Solar shingles, or photovoltaic shingles, are designed to look like conventional asphalt shingles, which when applied, have five inches of exposed area and are a dark purplish-blue colour – similar to most other roofs.
Solar shingles can be installed in ten hours – 12 to 20 hours quicker than the installation of traditional panels – and the lower cost of installation dramatically reduces the cost of solar power implementation.