Replace or repair? Reading the signs
Most flat roofs give plenty of warning before they fail. Water pooling for days after rain, blisters and cracks in old felt, damp patches on the ceiling below and a deck that feels soft underfoot all tell you something is wrong. The question is whether the problem sits in one spot or across the whole surface.
If a single seam has lifted or a small area has been damaged, a targeted repair can buy years of service, and we will tell you so. If the felt is brittle everywhere, or the timber deck underneath has started to rot, patching just moves the leak somewhere else. In that case a full strip and replacement is the cheaper option over time. Our roof repairs page covers smaller fixes in more detail.
GRP fibreglass roofs: what's involved
GRP stands for glass reinforced plastic. We strip the old covering back to the joists, check and replace any decking that is past its best, then lay new boards. A resin is applied and a glass fibre mat is worked into it so the two bond into a single seamless layer. Once that has cured, a coloured topcoat goes on to protect it from the weather.
Trims around the edges are fitted before the laminate, so the finished roof has neat, sealed edges rather than flapping felt. Because it is one continuous sheet with no joints, GRP is well suited to roofs that people may walk on occasionally, such as a balcony or a roof that needs regular access for maintenance.
EPDM rubber roofs: what's involved
EPDM is a synthetic rubber membrane supplied in large sheets. On most domestic roofs it can be laid in one piece, which means no seams across the middle where water could find a way in. The membrane is bonded to a clean, dry deck with adhesive, and edges and upstands are dressed and finished with trims.
Rubber stays flexible through hot summers and cold snaps, so it copes well with the movement that every flat roof goes through. It is a good fit for simple, regular shapes such as a garage or a single-storey rear extension. Where a roof has lots of awkward details, Lee will talk through whether GRP or EPDM is the more practical choice.
Garages, extensions and dormers
The flat roofs we see most often are on detached and attached garages, kitchen and living room extensions, porches and box dormers. Each one has its own quirks. Extensions usually meet the main house wall, so the join needs proper flashing. Dormers sit high up and are often tucked between tiled slopes, so access and edge details take planning.
Where a flat roof meets a pitched roof, we look at both. There is no point fitting a new rubber roof if the tiles above are shedding water straight onto it. If the main roof needs attention too, our new roofs team can price both together, and we cover the wider picture on the main roofing page.
How Lee runs a flat roof job, from quote to finish
Every job starts with a free site visit. Lee looks at the roof, the deck, the edges and the room underneath, then explains what he has found in plain terms. You receive a written quote setting out the system, the materials and what is included, so you can compare it fairly.
On the day, the old roof is stripped and the deck checked before anything new goes down. We work to keep the property watertight between stages and tidy up as we go. Lee oversees every job himself, so the person who quoted is the person checking the finished roof. Once the work is complete, we walk you round it and answer any questions.
Insulation, drainage and the details that matter
A new flat roof is a good chance to improve how warm the room underneath feels. Where it suits the build, insulation boards can be added as part of a warm roof build-up, and Lee will explain whether that is practical for your extension or garage before you commit.
Drainage deserves just as much thought. A flat roof is never perfectly level; it needs a gentle fall so rainwater runs towards a gutter or outlet rather than sitting in puddles. When we replace the deck, we check those falls and correct them where needed. We also look closely at upstands against walls, edge trims, outlets and any roof lights, because those junctions are where most flat roof leaks begin. Getting them right at the start is far easier than chasing a drip after the job is finished.
Felt still has a place on some roofs, particularly where a sound covering just needs a local repair. Where we recommend moving to GRP or EPDM instead, we will explain the reasons so the choice is yours.
Flat roofing across Essex and east London
We are based at 75a Church Street in Witham and work right across Essex and the Essex side of London's outskirts. We have pages for some of the towns we visit most often:
- Roofer in Chelmsford
- Roofer in Colchester
- Roofer in Romford
- Roofer in Southend-on-Sea
- Roofer in Basildon
- Not listed? Get in touch and ask. If you are in Essex or east London, we can usually help.
Roofing guides
Weighing up a new flat roof? Start with these.