Flat RoofingContractors

Repairs and surveys

Flat roof surveys and leak tracing across London

Not every flat roof in London needs replacing, and not every leak can be patched. A survey separates the two. It tells you whether the problem is isolated or widespread, whether the deck and insulation are sound and how long a repair is likely to hold, so you can decide with confidence.

Moisture meter being used on a flat roof membrane during a condition surveyComputer-generated example image
Guide price
£180–£360
Repair price
Confirmed once the leak or damage is found
Condition survey report
£180–£360
Coverage
England, Wales, Scotland, NI

London at a glance

Largest towns
Westminster, Camden, Islington, Haringey
Postcode areas
BR, CR, DA, E, EC, EN, HA, IG, KT, N
Building control
City of Westminster, London Borough of Camden, London Borough of Islington and 29 other councils
Neighbouring areas
Surrey · Hertfordshire · Buckinghamshire · Berkshire
Guide price region
London (+20% on West Midlands rates)

How much does a flat roof survey cost in London?

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

JobGuide price inc VAT
Condition survey and leak investigation£180–£360
Localised patch repair£180–£600
Upstand or flashing repair£300–£780
Emergency temporary weatherproofing visit£220–£540

Which flat roofs are common in London?

Flat roofs in London sit on Victorian and Edwardian terraces with flat-roofed back additions, mansard and dormer loft conversions and shops with flat-roofed stores below flats above. The Thames basin is one of the drier parts of Britain at roughly 730 mm of rain a year, but summer heat is the bigger test here: dark membranes on south-facing roofs swing a long way in temperature. 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 London the application goes to City of Westminster, London Borough of Camden, London Borough of Islington and 29 other councils. More on the rules.

What does a flat roof survey report cover?

The report sets out what the roof is, what condition it is in and what we recommend, in plain language.

  • The roof system, approximate area and how the roof is built, as far as can be seen.
  • The condition of the covering: splits, blisters, crazing, lost chippings, open laps and wear.
  • Upstands, flashings, edge trims and rooflights.
  • Falls, ponding and the state of outlets and gutters.
  • Moisture readings and the findings of any core samples.
  • The likely cause of any leak, and how confident we are in it.
  • Recommended action, ranked by urgency, with guide costs.

We are clear about what we could and couldn't see. A survey can't inspect hidden timbers without opening them up, and we will say where a finding is an inference rather than a direct observation.

How long does a flat roof survey take and how long is it valid?

A survey of a typical garage or extension roof usually takes an hour or two on site. Larger, higher or multi-area roofs take longer, and the written report follows afterwards.

A survey describes the roof on the day it was inspected. It stays a useful baseline for planning, but roofs change, particularly older ones and after a hard winter or a storm. If you are using a report to plan a replacement some time later, or after a fresh leak, a short follow-up check is sensible. For roofs you manage over the long term, a regular inspection backed by the maintenance checklist picks up problems early.

Which towns in London do we cover?

Flat roof surveys and leak tracing in London: questions

Which towns in London do you cover?

All of London. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.

How much does a flat roof survey cost in London?

£180–£360 for a condition survey and leak investigation, at London guide rates including VAT. We confirm the price once we've traced the leak or seen the damage.

Which postcode areas do you cover in London?

All of London, including the BR, CR, DA, E, EC, EN, HA, IG postcode areas. Send your full postcode and we'll confirm.

Do I need a roof survey when buying a house with a flat roof?

It's worth considering if the general survey flags damp, ponding or an ageing covering, or if the roof is large. A specific flat roof report gives you a clearer idea of what work may be needed and what it might cost.

Do you survey commercial and block roofs?

Yes. We survey flat roofs on shops, offices, units, blocks of flats and HMOs, with the report structured so a landlord, managing agent or owner can plan and budget the work.

Is a core sample damaging to the roof?

It's a small, deliberate opening that is sealed again with compatible material before we leave. It shouldn't affect how the roof performs.

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