The flat roof construction originated in the Middle East, where the weather is dry most of the time. In Europe, a flat roof is relatively a new way to build a roof. A flat roof is never really a flat roof as the name suggests, it will always have a slope to allow the water to drain off.
When replacing or building a flat roof, there are four popular options in terms of materials and costs.
Bitumen felt flat roofing
In UK, the most popular type of flat roof roofing is made of bitumen felt to provide a waterproof covering.The materials used for this type of roofing are cheap and the roofers will charge less than for other types of roofing.The felt roofing will have to be replaced from time to time, as it has a life span of maximum 10 years, depends on how exposed the roof is to the elements ( sun, rain, cold ).
Bitumen felt flat roofing with two skylights over a kitchen extension
Fibre Glass flat roofing
The materials cost is more or less double of the cost for a felt roof but it will last longer as most fibreglass roof manufacturers will provide a warranty of 20 years or more. It can also be cleaned very easily.
Fibreglass roofing with a Velux window over an infill extension
Lead flat roofing
A very traditional way to build a flat roof, more often than not, it is required for Listed Buildings and for buildings located in a Conservation Area. A lead roof can have a life span of over 50 years, provided that there is ventilation for the wood work. It has to be painted with patination oil to stop the lead from staining.
Lead flat roofing over a rear extension
Asphalt flat roofing
Asphalt roofing is hot and melted bitumen mixed with aggregate. It has passed the test of time, it contracts when its cold and expands when its hot. White coloured asphalt reflects the heat better but it gets dirty very quickly.
Asphalt roofing and conservation roof window over a garage conversion