Flat roof repairs across West Sussex

Guide price

£170–£550

Repair price

Confirmed once the leak or damage is found

Condition survey report

£170–£330

Coverage

England, Wales, Scotland, NI

How much does a flat roof repair cost in West Sussex?

Guide prices including VAT at South East rates. We confirm the price once we've traced the leak or seen the damage.

Which flat roofs are common in West Sussex?

Flat roofs in West Sussex sit on shops with flat-roofed rear stores below flats, low-rise post-war blocks of flats and terraced streets with flat-roofed rear kitchens and bathrooms. Much of the South East sits in the drier Thames catchment at roughly 730 mm of rain a year, so the usual failures are at joints, upstands and outlets rather than from sheer volume of rain. Approximate 1991–2020 regional averages based on Met Office data.

Building regulations in England

Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In West Sussex the application goes to Crawley Borough Council, Worthing Borough Council, Arun District Council and 4 other councils. More on the rules.

Why does a flat roof leak in one place but drip somewhere else?

Because water rarely comes through the ceiling directly below the hole. It gets in at one point, runs along the deck, a joist or the top of the insulation, and drips wherever it finds a low spot or a gap in the ceiling.

That is why a patch over the damp patch so often fails. Before we repair anything, we work back from the stain to the likely entry point and check the usual weak spots: upstands where the roof meets a wall, flashings and cavity trays above them, laps and seams, outlets and gutters, drip trims, rooflight kerbs, and any fixings or cables that pass through the covering. The fault is frequently at an edge or a wall rather than in the middle of the roof.

Sometimes the cause isn't the roof at all. Defective pointing, a failed cavity tray or a cracked coping above the roof can let water in behind the upstand, and condensation in a cold roof can look exactly like a leak. Our guide to flat roof leaks covers these causes. If the path can't be found by inspection, a leak tracing survey is the next step.

Should I repair or replace my flat roof?

Repair it if the defect is isolated and the rest of the roof is sound, dry and still well within its working life. Replace it if leaks keep coming back, cracking or blistering is widespread, the insulation is wet or the deck feels soft underfoot.

A useful test is to ask whether a repair would still look sensible if a second leak appeared somewhere else a few months later. On a roof near the end of its life, patching one split tends to move the problem rather than solve it, and repeated call-outs soon add up to a large share of the cost of a new roof. On a roof that is a few years old with one storm-damaged lap, a repair is the right answer and we will say so.

Our repair or replace guide sets out the signs in more detail, and the lifespan guide gives typical service lives for each system.

Which towns in West Sussex do we cover?

• Crawley
• Worthing
• Bognor Regis
• Littlehampton
• Horsham
• Haywards Heath
• Chichester
• Burgess Hill
• East Grinstead
• Shoreham-by-Sea
• Lancing

Everything about flat roof repairs → · All flat roofing in West Sussex →