Roof repairs in Lewisham

Most roof problems in this part of London are repairable. The skill is in working out which defect is actually causing the symptom — and being honest about when a repair is no longer the sensible answer.

We repair pitched and flat roofs across the London Borough of Lewisham. The housing stock here is heavily weighted towards Victorian and Edwardian terraces with slate or clay tile main roofs and flat-roofed rear back-additions — a combination that produces a fairly predictable set of faults, and a well-known set of leak points where the two meet.

Pitched roof repairs

• Slipped and broken slates or tiles. On Victorian slate roofs the usual cause is nail fatigue — the fixings corrode and slates slip one at a time. Whether that is a repair or the start of a re-roof depends on the pattern: see slate roof repair.
• Ridge, hip and verge mortar. Bedding dries, cracks and releases, which is both a leak risk and a genuine safety issue in wind. See ridge and verge repair.
• Valleys. Where two slopes meet, water is concentrated. Lead valleys fail at fixings and laps; mortar-filled valleys crack.
• Chimney junctions. Extremely common, and covered in detail on our flashing repair page.
• Underlay failure. Older bitumen felt becomes brittle and tears, so water that gets past the covering is no longer caught.
• Party wall and abutment details where a roof meets a neighbouring elevation or a rear extension wall.

Flat roof repairs

Rear extensions, back additions, dormers and outriggers across Lewisham are overwhelmingly flat-roofed, and they cause a disproportionate share of leaks — almost always at the edges rather than in the middle. Splits, blistering, ponding, failed upstands and blocked outlets are covered in detail on the flat roof repair page, along with parapet and box gutters.

Repair or replace?

An honest answer needs the roof looked at, but the general principle is this: repair when the defects are localised and the covering as a whole has life left in it; replace when the same slope keeps failing in new places.

The arithmetic that matters is not repair cost versus replacement cost, but repair cost multiplied by how often you will be doing it. We set that out in full, along with what drives the price either way, on the roof repair cost page — and the specific case of a slate roof reaching the end of its fixings is covered under slate roof repair.

We will tell you if we think you are about to spend money that only buys a season. Equally, we will not tell you a roof needs replacing when a repair will genuinely do — a great many "you need a new roof" verdicts are avoidable.

Gutters, fascias and rainwater goods

A surprising proportion of "roof leaks" are actually rainwater problems: blocked gutters overflowing behind the fascia, split downpipes soaking a wall, or a gutter falling away from its line so water discharges against the brickwork. These are cheap to fix and expensive to ignore. See gutter repair, which includes a table for telling a gutter problem from a roof leak.

How we approach a repair

1. Find the actual cause. Water travels. The point where it appears inside is often well away from where it entered. Where relevant we look in the loft as well as on the roof.
2. Report what we find, including anything else visible that will need attention later — so you can plan rather than be surprised.
3. Quote in writing, with access costs stated separately.
4. Carry out the repair using materials appropriate to the existing roof, matching slate or tile type where we are replacing units.

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