Flat roofs can strike fear into the hearts of many people but they have come a long way from the problematic, leak-prone versions of the 1980s and before. Nowadays, a well designed and waterproofed flat roof should not cause problems or leak.
Most flat roofs are not actually flat: they have a slight slope to allow rain water to drain off. They are economical to build and allow homeowners to maximise floor-to-ceiling heights.
One of the most common problems encountered with flat roofs is rainwater outlets becoming blocked with leaves. To help prevent this you should allow for more than one outlet to drain an area and provide leaf guards to all outlets.
It’s wise to inspect your roof particularly in the autumn and clear them before an issue arises.
Poor workmanship is another source of problems with flat roofs. Before you employ a roofing contractor check their references and engage an engineer, or architect, to specify, detail and inspect the work.
There are three main flat-roof systems: rubber, fibreglass and torch-on felt. But how do they compare?
The cheapest of the three is the torch-on felt roof. But this finish does still carry a bad reputation from the older, and now unused, pour and roll systems of the past.
The new versions are far more flexible and durable. Three layers of felt are melt welded together with a large blowlamp or torch; hence the name torch-on felt.
The top layer is called a cap sheet which can either be in plain black bitumen, a solar reflective paint, or a mineral fleck which comes in a variety of colours.
Most have 10-year guarantees but a well installed torch-on felt roof could well last up to 30 years if looked after and treated well.
Foot traffic in hot weather may scuff the surface of a mineral finish which can lead to UV sun damage.