Start with an assessment, not a tin of sealant
A good repair depends on knowing what has actually failed. When Lee visits, he walks or inspects the surface, presses for soft spots in the deck, checks the edge trims, outlets and upstands, and looks at the ceiling or garage underneath to see how far the water has travelled.
If you are still trying to work out where the water is coming from, our flat roof leaking page lists the usual causes and what you can safely do before we arrive. This page is about the repair itself.
Three ways to fix a flat roof
Every repair we quote falls into one of three options:
- Patch repair: a split, blister or lifted seam is cut out and a new piece of matching material is bonded over it. Best when the rest of the covering is sound.
- Overlay: on some felt roofs a new layer can go over the old one, but only where the deck is dry and firm and the extra height will not cause problems at doors or flashings.
- Strip and replace: when the felt is brittle everywhere or the deck is wet, the roof comes off and a new GRP or EPDM roof goes on.
Felt roof repair
Most flat roofs we repair are still felt. Typical felt roof leak repair work includes resealing lifted laps, reforming upstands against walls, replacing perished edge flashings and torching new cap sheet over a damaged area. Where gravel or chippings have been washed away, the exposed felt degrades faster, so we look at that too.
The felt roof repair cost depends on the size of the damaged area, whether any decking has to be cut out, access and the condition of the edges. Lee gives you a fixed written price, and he will tell you honestly if the money would be better spent on a replacement.
Repairing GRP and rubber roofs
Modern systems need the right materials. On a fibreglass roof we cut back and relaminate cracked areas; on rubber we patch with compatible membrane, primer and seam tape. Using bitumen on either usually makes a later proper repair harder. See GRP fibreglass roofing and EPDM rubber roofing for how each system is built.
Garages, extensions and dormers
Garage roofs make up a big share of our flat roof repair calls, often because they were built with cheaper materials and have been ignored for years. If yours is past repair, our garage roof replacement page explains what is involved. For tiled roofs or a mix of both, see our general roof repairs service.
Booking a flat roof repair
Call Lee on 07947 758052, Monday to Friday, 8am to 5pm, or send us the details online. Active leaks are prioritised. It helps to know roughly how old the roof is, what it is covered in, and where the water is showing inside.
Signs a flat roof repair is due
Flat roofs give warnings. Watch for water that sits for more than a day or two after rain, bubbles or blisters in felt, cracked or curling edges, gravel washed into the gutters, and damp marks or mould on the ceiling below. Inside a garage, look up at the boards for dark staining. Catching these early often keeps the job to a small repair rather than a new roof.