Flat roof repairs

When a repair is the right answer

Repair makes sense when:

• The bulk of the roof membrane is sound and has plenty of life left;
• The failure is localised — a single split, one failed upstand, one outlet, one chimney detail;
• The cause of the failure is something specific we can fix (rather than systemic membrane degradation);
• The age of the roof is less than 70% of its expected lifespan.

When a re-roof is the right answer

Replacement makes sense when:

• The membrane has been patched three or more times in the same general area;
• The cap sheet shows widespread cracking, alligatoring or aggregate loss across most of the surface;
• You can see daylight through any part of the roof from inside;
• The deck below has rotted in patches and needs significant replacement;
• The roof has reached or passed its expected lifespan and is leaking;
• The cost of an estimated repair plus the next likely repair within 3 years exceeds 50% of replacement cost.

The middle ground — overlay

Often the best answer for a 15–20 year-old felt roof in moderate condition is an overlay: a new membrane laid directly over the existing roof rather than stripping back to deck. Done correctly, an overlay gets you 80% of the lifespan of a full re-roof at 50–60% of the cost. The reason we don't always recommend it is that:

• It doesn't give you the chance to upgrade the insulation (which is often badly needed on older buildings);
• You're sealing in whatever is wrong with the existing roof, including any trapped moisture in the build-up;
• It adds height to the roof which can cause issues at lead apron flashings and upstands.

We'll consider an overlay when: the existing roof is dry (no signs of trapped moisture), insulation upgrade isn't critical, the height increase is manageable at the perimeter detail.

Warranty on repairs

All repair work carries a 12-month workmanship guarantee. That's deliberately calibrated to one full winter cycle — the season in which most fitting faults reveal themselves. If you see the same problem return within 12 months, we come back and fix it at no charge — no call-out fee, no out-of-scope arguments.

Underlying membrane failures (existing material continuing to degrade in a different spot) aren't covered by repair warranty — they're a separate event. We'll always tell you at quote stage if we think there's a high probability of secondary failures within the year.

How quickly we can come

Active leaks into the building: same day, usually within 60–90 minutes locally. Storm damage: same or next day. Non-urgent repairs: within 1–2 weeks. Full re-roofs: scheduled 3–6 weeks ahead based on diary availability.