Roofs are different where you go. Just about every building around the world has one, but they vary in shape, materials, durability and construction. Why is this so and why has not someone come up with the definitive roof for all roofers to copy?
Depending where in the world you live roofs have a variety of purposes. Primarily they are to protect against rainfall, but also they give shelter from sun, wind, cold and heat. Characteristics also differs according to local architectural style, available materials, wealth and the purpose of the building.
The main impacts on the shape and look of a roof are the materials available, on how the roof is supported and on whether the roof is pitched or flat. Roof support is usually provided by timber, bamboo, cast iron, steel or metal rods encased in reinforced concrete. Bamboo is very flexible and so in Asia, where it is commonly used, roofs are often curved. Timber is versatile and can provide virtually any shaped roof – from low and high pitch to dome shapes. Metal supports are good for large, heavy roofs.
Once the internal supports are in place, the outer skin, which weatherproofs the building, needs to be added. Again, materials vary from banana leaves in Africa to rice straw that in Japan, slate in Europe and the USA, terracotta tiles in the Mediterranean and copper and zinc around the world.
These materials have an impact not only on durability but also on design. Thatch generally needs to be steeply pitched to make it effectively weatherproof, although in dry climates, this is not so important. Slate is an ideal material – it is durable and can easily last 150 years or more, if weather-resistant nails are used to secure the slates.
Sheet metals such as copper and lead are also very durable and popular, and have been used for several centuries. Even though metal roofs are expensive they age well (copper turns to a pale green with oxidization) and can last for hundreds of years. Due to their expense they have in the past been used on cathedral roofs and the roofs of palaces and chateaux. More recently cheaper metal options have been developed, such as zinc-plated iron. These lighter weight and less durable than other metal roofs but are popular on industrial buildings.
The most up-to-date materials include green roofs, which use living vegetation to absorb carbon dioxide and release oxygen, helping to create a healthy environment and to combat global warming. Fiberglass, bitumen and glass also have their place and are popular with architects. Glass can let in light while keeping out wind and rain and is popular both in large buildings, such as grand railway stations and art galleries and in homes to create conservatories and skylights.
With the globalization of material availability and the increase of wealth generally it is getting easier to copy styles and the best features of roofs from different places. Architects have always wanted to be bold and break new ground and that ensures the development of roof styles. Increasingly environmental needs will also have their part to play – hence the proliferation in green roofs and solar panels.
But the basics will remain – areas of high rainfall and snow such as Scandinavia will continue to have high pitched roofs. Dry areas such as the Middle East will stick with the simplicity of flat roofs as they have little rain to deal with. In addition many Governments are increasingly protective of local style and resistant to design which ignores regional tradition and taste.
Roafers around the world have different methods and materials to work with and this will always encourage a range of roofs to enrich our skylines.