Cambridge Roofers installs and repairs flat roofs across Sawston and the surrounding area, and we want every job we do to stay watertight for as long as possible - which means giving homeowners the information they need to look after it properly.
Call any time. Calls are answered day and night and passed straight to our roofers.
A well-installed flat roof - whether EPDM rubber or a quality torch-on felt system - should give you many years of service without trouble. But even the best installation can be undermined by simple, avoidable problems. Most flat roof failures that bring a roofer back within a few years of a new installation are not caused by faulty materials or poor workmanship. They are caused by drainage that was never cleared, debris that sat on the roof for too long, or a small defect that was spotted too late.
The good news is that looking after a flat roof does not require specialist knowledge or any tools beyond a ladder and a bucket. It mostly requires doing a few simple things at regular intervals.
The single most important maintenance task on any flat roof is keeping the drainage outlet clear. Flat roofs drain through one or more outlets set into the membrane. Leaves, moss, dirt and debris collect around these outlets and block them. When an outlet is blocked, water backs up across the roof surface. Standing water increases the load on the structure, accelerates the aging of the membrane, and finds its way through any weak point - a small blister, a poorly dressed edge, a loose upstand.
Clear the outlet by hand every autumn after the leaves have fallen. Remove any debris from around the drain cover, lift the cover if it is removable, and check the outlet is running freely. If the downpipe from the outlet is slow to clear, that is a sign of a blockage lower down that should be dealt with before winter.
Leaves, twigs and general debris hold moisture against the membrane surface. Damp debris sitting on felt or EPDM for extended periods accelerates surface degradation. It can also hide damage - a small split or puncture that you would catch early if the surface were clear.
A quick sweep of the roof surface in autumn and again in spring takes ten minutes and makes a real difference. If there are trees overhanging the roof, it is worth doing it more often. You do not need to walk across the membrane to do this - a soft-bristled broom on a long handle works perfectly well from the edge.
The edges and upstands of a flat roof - where the membrane turns up against a wall, parapet or dormer - are the places most likely to develop problems first. The membrane is bonded or secured at these points, and over time, thermal movement (the membrane expanding and contracting with temperature changes) can cause the edge detail to lift slightly.
Once a year, take a look at the upstands. You are looking for any section where the membrane has pulled away from the wall surface, or where the termination bar at the top of the upstand has lifted. A gap of even a few millimetres is enough for wind-driven rain to get behind the membrane. Catching it early means a straightforward repair; leaving it means water gets into the wall and the deck beneath.
Check the drip edge along the perimeter of the roof too. The trim that finishes the edge of the membrane should sit flat and be firmly fixed. If any section has lifted or the membrane is peeling back from it, that needs attention before water tracks back under the covering.
Blisters in a felt membrane look alarming but are not always a sign of imminent failure. A blister forms when moisture or air is trapped beneath the felt during installation and expands with heat. Small, firm blisters that have been stable for years may not be causing any immediate problem. Large blisters, or blisters that are soft and flexible underfoot, are more concerning because the felt in those areas is no longer bonded to the deck.
Do not pierce a blister to let air out - this breaks the membrane surface and creates an immediate entry point for water. If you find blisters on your roof, note their size and location and mention them when a roofer comes to inspect the roof. They can be patched if caught in time.
EPDM rubber roofs do not blister in the same way felt does, but the membrane can develop areas of pooling where the surface has sagged slightly. If you notice water sitting in a low point long after rain has stopped, that is worth keeping an eye on.
Cold weather puts stress on any flat roof. Frost causes materials to contract, and repeated freeze-thaw cycles can open up small gaps at edges and seams. After a hard frost, it is worth taking a look at any upstands and edge details from the ground or from a ladder if it is safe to do so. You are not looking for anything dramatic - just any visible change from how the roof looked before winter.
Torch-on felt is more susceptible to cracking in very cold temperatures if it has aged and become brittle. If you have a felt roof that is more than 15 years old, a post-winter inspection by a roofer is a sensible precaution, particularly if you notice any staining on ceilings below the roof after cold spells.
Some things should not be monitored and left. Call a roofer promptly if you notice:
Each of these, caught early, is a repair job. Left, each becomes a larger and more expensive problem - and in some cases means the deck beneath the membrane has been compromised, which changes the scope of the work entirely.
A flat roof installed with correct fall, sound decking and properly detailed edges needs relatively little intervention between inspections. EPDM installed correctly can last 25 years or more. Torch-on felt in three layers, on a sound deck with adequate fall, typically performs well for 15 to 20 years. Aftercare does not change those figures dramatically, but neglect can cut them significantly.
Flat roofing costs in the UK typically run between £70 and £120 per square metre for EPDM and £50 to £90 per square metre for torch-on felt, for a complete replacement job. A small repair - clearing a blocked outlet or redressing a lifted upstand - is a fraction of that. Maintenance is about keeping you in the cheaper category for as long as possible.
We cover Sawston and the area around Cambridge, including neighbouring villages and towns. If your flat roof is due an inspection, or if you have spotted something during your own checks that you want looked at, call us to arrange a visit and we will tell you plainly what we find and what, if anything, needs doing.
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Call any time. Calls are answered day and night and passed straight to our roofers.
