Flat RoofingContractors

Flat roof systems

Mastic asphalt roofing across Surrey

Across Surrey, many older houses, mansion blocks and commercial buildings still have asphalt roofs, some of them original to the building. Our trained teams working under S&K repair them in fresh asphalt, overlay sound roofs with compatible systems, or replace failed roofs, keeping the building weathertight and following strict hot-works control from the first day of the job to the last.

Specialist spreading hot mastic asphalt on the roof of a Victorian mansion blockComputer-generated example image
Price per m²
£94–£165
Typical life
30–60 years
Manufacturer guarantees
15-year material, up to 25-year system guarantees
30 m² roof
£3,800–£6,850

Surrey at a glance

Largest towns
Woking, Guildford, Esher, Redhill
Postcode areas
CR, GU, KT, RH, SM, TW
Building control
Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils
Neighbouring areas
London · Berkshire · West Sussex · Buckinghamshire
Guide price region
South East (+10% on West Midlands rates)

How much does mastic asphalt roofing cost in Surrey?

Guide prices including VAT at South East rates. The fixed price comes after a free survey for new and replacement roofs.

JobGuide price inc VAT
Mastic asphalt roof (30 m²), scaffold£3,800–£6,850
Localised patch repair£170–£550
Single garage (18 m²), EPDM rubber£1,750–£3,100
Extension (20 m²), EPDM, new deck + insulation£3,100–£5,350

Which flat roofs are common in Surrey?

Flat roofs in Surrey sit on terraced streets with flat-roofed rear kitchens and bathrooms, lock-up garage blocks on estates and 1930s semis with flat-roofed garages and kitchen extensions. 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 Surrey the application goes to Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils. More on the rules.

Should an old asphalt roof be repaired, overlaid or replaced, especially on a heritage building?

If the asphalt is sound apart from local cracks or blisters, repair it; if it is crazed and tired but dry and well bonded, consider an overlay; if it is leaking widely, sitting on a wet or failing deck, or full of trapped moisture, replace it. A survey, sometimes with a leak trace, tells you which applies.

  • Repairs: blisters are cut out, cracks opened up and fresh asphalt worked in by a specialist, so the repair fuses with the existing roof.
  • Overlay: a compatible system, often a reinforced liquid membrane, is bonded over the old asphalt after cleaning and priming. This keeps the old asphalt as a solid base and avoids heavy strip-out.
  • Replacement: the old asphalt is broken out and the roof rebuilt, either in new asphalt or in another system the structure can carry, with insulation where required.

On heritage and older buildings, matching the original material and detailing often matters as much as waterproofing. New asphalt skirtings and aprons can follow the existing lines, and any change of material on a listed building should be agreed with the conservation officer before work starts.

Asphalt work is a specialist trade. It needs mixers or boilers on site, trained asphalters and strict hot-works control, so we plan these jobs around access, the building's occupants and the weather.

How long does mastic asphalt last, and what guarantees are available?

Mastic asphalt is one of the longest-lasting flat roof systems, typically giving 30 to 60 years with good specification and maintenance. Many older asphalt roofs are still watertight decades after they were laid.

Age does show eventually. Common signs include crazing and cracking from sun exposure, blisters where moisture has been trapped beneath, splits at skirtings where the building has moved, and ponding where the deck has settled. Regular maintenance, such as renewing solar reflective paint, keeping outlets clear and repairing cracks early, makes a real difference to life.

Material and system guarantees are available on some specified asphalt systems, and we register them for you where the system allows. Every re-roof carries our written workmanship guarantee, with the length set out in the quote, and insurance-backed options can be discussed. Our lifespan guide compares asphalt with the other systems.

Which towns in Surrey do we cover?

Mastic asphalt roofing in Surrey: questions

Which towns in Surrey do you cover?

All of Surrey. 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 mastic asphalt roofing cost in Surrey?

£3,800–£6,850 for a 30 m² mastic asphalt roof including scaffold, at South East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

Which council handles building control for a flat roof in Surrey?

It depends on where the roof is: in Surrey that's Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils. 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. We confirm which applies at the survey.

Why is my asphalt roof cracking?

Asphalt typically cracks as it ages and becomes brittle from sun exposure, or where the building moves at skirtings and junctions. A solar reflective paint and early repairs help slow it down.

Why are mastic asphalt roofs painted silver or white?

The reflective coating keeps the asphalt cooler in sun, reducing softening and slowing the surface ageing that leads to crazing. It usually needs renewing every few years as part of maintenance.

Is mastic asphalt suitable for a balcony or terrace?

Yes, asphalt is traditionally used on terraces and walkways because it takes foot traffic well, often with paving on top. A new balcony or terrace generally needs planning permission, so check before converting a roof.

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