The three systems we fit — and when each wins
GRP fibreglass is a seamless, wet-laid system that cures into one solid waterproof shell. No joints means nowhere to leak, and it takes foot traffic well — ideal for extensions, balconies and roofs you might walk on. EPDM rubber comes as a single sheet cut to your roof, glued down in one piece. It's fast to install, flexible in all temperatures and brilliant value on garages and outbuildings. High-performance felt (torch-on, three-layer) is still the right call on some detailed roofs and for like-for-like insurance work — modern felts are miles beyond what gave felt its reputation.
We'll recommend whichever suits your roof's shape, use and budget, and tell you honestly when the cheaper option is genuinely fine.
Warm roofs, insulation and building regs
If your flat roof is over a living space — an extension, a dormer bedroom — building regulations require insulation to be upgraded when the covering is replaced. We build these as warm roofs: rigid insulation boards above the deck, which stops condensation forming inside the structure and makes the room below noticeably warmer. It adds a little height and cost, and it's worth every penny. Garages and sheds can usually stay as simple cold roofs.
Repairs, ponding and honest advice
Not every tired flat roof needs replacing. Blisters, small splits and failed joints on an otherwise sound roof can often be repaired for a couple of hundred pounds. Persistent ponding — water still sitting there days after rain — usually means the falls (the slight slope) were never right; we fix that with tapered insulation when we re-cover rather than just papering over it. Wondering what shape yours is in? Run through our two-minute roof health check and see what it says.