Flat Roof Repairs — North London
Flat Roof Repairs That
Stop the Leak and Fix
the Root Cause
Patching a flat roof without diagnosing the underlying problem is throwing money away. We find the real cause, repair it properly, and guarantee the fix — so you only pay once.
★ Repairs all systems (felt, EPDM, GRP) · Same-day service · Fixed-price quotes
When Does a Flat Roof Need Repairing?
Flat roofs need repair when their waterproof membrane has been compromised — whether by age, storm damage, impact, or poor original installation. Common signs include water stains on the ceiling below, blistering or bubbling on the roof surface, ponding water that doesn't drain within 48 hours, and visible cracks or splits in the membrane.
The challenge with flat roof repairs is accurately diagnosing where the water is actually getting in. Water on a flat roof can travel horizontally along the deck before finding a gap to drip through, meaning the leak on your ceiling might be metres away from the actual point of entry on the roof surface.
At AC Roofing & Carpentry Ltd, we repair all types of flat roofs including felt, EPDM rubber, GRP fibreglass, asphalt, and single-ply membrane systems. Our repair process always starts with diagnosis — we trace the leak back to its source and fix the cause, not just the symptom.
We provide flat roof repairs across North London with same-day availability for urgent leaks. Most repairs are completed in a single visit, and every repair comes with a fixed-price quote and written guarantee.
Real Work
See Our Flat Roof Repair Projects
Why Most Flat Roof Repairs Fail Within a Year
The roofing industry's dirty secret: most flat roof repairs fail because the roofer fixed the wrong thing. They see a crack, patch it, collect payment, and leave. But the crack was a symptom of ponding water caused by inadequate falls, and within six months the patch has failed and the leak is back — often worse than before.
Another common failure: using the wrong repair material. Applying a felt patch to a GRP roof, or using general-purpose sealant on EPDM. Each flat roofing system requires its own repair materials and techniques. Using the wrong ones creates a repair that looks fine initially but has no chemical bond with the existing membrane and fails rapidly.
DIY flat roof repairs are particularly problematic. The products sold at DIY stores — brush-on sealants, self-adhesive patches, bitumen paint — are designed for temporary emergency use, not permanent repair. They break down under UV exposure and thermal cycling within months. Homeowners who've applied multiple layers of bitumen paint have often made the eventual professional repair more difficult and expensive.
The financial reality: paying £200 for a bodge repair three times costs more than paying £400 for a proper fix once. Every failed repair also means more water damage to the structure beneath, which adds to the final bill when the job is eventually done correctly.
How We Work
Our Flat Roof Repair Process
Leak Tracing
We trace the water path to identify the actual entry point — not just the drip.
Root Cause Analysis
We determine why the failure occurred — age, ponding, impact, or installation defect.
Material-Matched Repair
We use repair materials specifically designed for your flat roof system.
Drainage Check
We verify water flow and falls to prevent future ponding.
Test & Guarantee
Water test where possible, clean-up, and written guarantee issued.
Why It Matters
Flat Roof Repairs Done Right
Accurate Diagnosis
We find the real cause, not just the visible symptom.
System-Specific Repairs
Correct materials matched to your existing roof system.
Same-Day Availability
Urgent leaks addressed the same day in most cases.
Fixed-Price Quotes
No call-out fees. No hidden charges. Clear pricing upfront.
Guaranteed Fix
Every repair backed by a written workmanship guarantee.
Honest Assessment
If repair isn't viable, we'll tell you — never patch what should be replaced.
Flat Roof Repair: Methods and Considerations
Felt Roof Repairs
Felt roof repairs involve cutting away the damaged section, drying the deck beneath, and torch-applying a new patch of compatible felt membrane. The patch must extend at least 150mm beyond the damaged area on all sides, with the edges fully sealed by heat welding. For blistered felt, we cut open the blister, press the felt flat, dry any trapped moisture, and apply a reinforcing patch. If blistering is widespread, it indicates the felt has reached end of life and replacement is more cost-effective than multiple repairs.
EPDM Rubber Roof Repairs
EPDM repairs require specific materials — standard adhesives and sealants don't bond to rubber. We use EPDM-specific primers, adhesives, and uncured rubber flashing tape to create repairs that have a genuine chemical bond with the existing membrane. Common EPDM repair points include seam separations, punctures, and edge lifting. Where seams have failed, we strip the old seam tape, clean and prime the surface, and apply new bonding adhesive and seam tape with roller pressure.
GRP Fibreglass Repairs
GRP repairs involve sanding the damaged area back to sound laminate, applying a new layer of catalysed resin and glass fibre matting, and finishing with a pigmented topcoat. GRP repairs are structurally strong and chemically bond with the existing laminate, creating a repair that's as strong as the original. Common GRP repair points include cracks at stress points (direction changes, upstand bases) and areas where the original laminate was too thin.
When Repair Isn't Enough
We'll always tell you honestly if a repair isn't the right approach. If the flat roof membrane has multiple failure points, if the deck beneath is rotten, or if the roof has been patched repeatedly and is more patch than original — replacement becomes the more cost-effective option. Continuing to repair a roof that's past its useful life is like filling a bucket with holes. We'll explain the options, provide costs for both repair and replacement, and let you make an informed decision.
Common Questions
Frequently Asked Questions
Protect Your Property Today
Speak to our team for honest advice and a no-obligation estimate. Most quotes delivered within 24 hours.