Although difficult to determine, it is estimated that approximately 75% of properties in the UK have some form of flat roof, whether that is the whole of the property, (many of the high-rise flats and commercial blocks in city areas will have flat roofs, they are needed to house all of the air con, telecoms, and other amenities), but its more likely that a garage or extension on a domestic property will have a flat roof installed.

In both Level 2 and Level 3 surveys, we examine the roofs, but obviously in greater detail in our Level 3 surveys. Here is what we look for on a typical flat roof.

The first thing we would look for is any obvious signs of leaking or damp. We visited a property last week for a Level 3 survey, and the flat roof over the porch had no gutters, so the water was coming off the main roof and falling over the side of the porch and down the exterior wall.

Its essential we understand the flat roof structure and that materials are laid on the surface, this could be either a fibre glass system, torch-on-felt, a rubber roof, or maybe a liquid resin.

We will be looking for pooling, which will indicate the incorrect levels on the roof, damage such a splits or rotting, which can happen when a roof hasn’t been maintained and had gone past its natural life expectancy. As with last week, are the current gutters and downpipes installed and have they been kept cleaned, especially in an area where trees are shedding?

We would then expect to look at the flashings and upstands in more detail, as long as we can gain safe access, it is often easy to spot a poor installation as there will be gaps between the flashing and the wall, which will create water damage to the OSB boards below the roof surface material.

We are also checking for any sagging or soft spots, especially when the weather is dry and there may be no water pooling This is a way to check the integrity of the surface below. And if a roof has been well maintained, there should be no vegetation growing off the roof surface or around the flashing.

Getting an accredited roofer is essential when installing a new or replacement flat roof, we would suggest you look at the NFRC website and find a local roofer in your area who has passed their rigorous inspection regime.

If you are buying a property with a flat roof, get in touch, don’t leave it to chance, you may not be able to see the issues, and it can be an expensive job replacing a flat roof on a property.