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Flat roof systems

Mastic asphalt roofing across County Durham

Across County Durham, 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
£79–£140
Typical life
30–60 years
Manufacturer guarantees
15-year material, up to 25-year system guarantees
30 m² roof
£3,200–£5,800

County Durham at a glance

Largest towns
Darlington, Hartlepool, Stockton-on-Tees, Durham
Postcode areas
DH, DL, SR, TS
Building control
Darlington Borough Council, Hartlepool Borough Council, Stockton-on-Tees Borough Council and 1 other council
Neighbouring areas
Tyne and Wear · Northumberland · North Yorkshire · Cumbria
Guide price region
North East (−7% on West Midlands rates)

How much does mastic asphalt roofing cost in County Durham?

Guide prices including VAT at North 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£3,200–£5,800
Localised patch repair£140–£470
Single garage (18 m²), EPDM rubber£1,500–£2,600
Extension (20 m²), EPDM, new deck + insulation£2,600–£4,550

Which flat roofs are common in County Durham?

Flat roofs in County Durham sit on lock-up garage blocks on estates, 1960s and 1970s link-detached houses with flat-roofed garages and porches and newer estates where the first extension roofs are now being replaced. England averages roughly 870 mm of rain a year; the North East is drier than the west but cold and windy near the coast, so wind uplift and freeze-thaw are in the specification. 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 County Durham the application goes to Darlington Borough Council, Hartlepool Borough Council, Stockton-on-Tees Borough Council and 1 other council. 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.

What building regulations apply when an asphalt roof is replaced?

Replacing more than half of an asphalt roof over a heated space usually counts as renovating a thermal element in England, Wales and Northern Ireland, so the roof should be insulated towards the renovation standard where technically and economically feasible; Scottish owners should check with the local authority's building standards service whether the work needs a warrant.

On older buildings, adding insulation can be constrained by parapet heights, door thresholds and the character of the building, and the regulations allow for what is technically feasible. In England, a new covering that adds 15% or more to the roof's weight also needs approval, so a switch to heavier asphalt is checked against the structure. Listed buildings may need listed building consent for changes to their character. We deal with building control or building standards where needed; see the building regulations page.

Which towns in County Durham do we cover?

Mastic asphalt roofing in County Durham: questions

Which towns in County Durham do you cover?

All of County Durham. 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 County Durham?

£3,200–£5,800 for a 30 m² mastic asphalt roof including scaffold, at North East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

Which postcode areas do you cover in County Durham?

All of County Durham, including the DH, DL, SR, TS postcode areas. Send your full postcode and we'll confirm.

How heavy is a mastic asphalt roof?

Considerably heavier than felt, rubber or single-ply, which is why it is usually laid on concrete or strong timber decks. We check the structure before recommending asphalt on any roof.

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.

Is mastic asphalt the same as tarmac?

No. Both contain bitumen, but mastic asphalt is a dense, voidless mix with fine limestone aggregate, made to be fully waterproof, while road surfacing is a different material.

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