DIY Flat Roof Repair: What You Can and Can't Do Yourself

We understand the temptation to fix a flat roof yourself — a tin of bitumen sealant from the builder's merchant is a lot cheaper than calling a roofer. But the wrong repair can actually make things worse. Here's an honest assessment.

Things That Are Genuinely DIY-Friendly

• Clearing moss and debris from the roof surface
• Cleaning gutters and drainage outlets
• Applying biocide treatment to prevent moss growth
• Temporary sealing with liquid rubber or roof repair tape — to stop a leak in an emergency, not as a permanent fix

Things That Need a Professional

• Any repair to GRP fibreglass (requires specialist materials and experience)
• EPDM seam repairs and full patches (adhesive types must be matched correctly)
• Flashing repairs at wall abutments (if done incorrectly, worse leaks result)
• Any repair where the cause of the leak hasn't been properly diagnosed
• Any structural work or roof decking replacement

The Risk of Wrong DIY Repairs

The most common problem we see is bitumen-based products applied over EPDM or GRP membranes. These materials are incompatible and can cause the membrane to delaminate or swell, turning a small leak into a much larger problem.

When to Call Us

If water is coming in, call a specialist. Emergency temporary repairs we do make are compatible with the existing system and won't cause further damage. A proper diagnosis from the outset saves money in the long run.