Flat RoofingContractors

Flat roof systems

Mastic asphalt roofing across Hampshire

Across Hampshire, 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

Hampshire at a glance

Largest towns
Southampton, Portsmouth, Basingstoke, Gosport
Postcode areas
BH, GU, PO, RG, SO, SP
Building control
Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 other councils
Neighbouring areas
Isle of Wight · Berkshire · West Sussex · Surrey
Guide price region
South East (+10% on West Midlands rates)

How much does mastic asphalt roofing cost in Hampshire?

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 Hampshire?

Flat roofs in Hampshire sit on 1930s semis with flat-roofed garages and kitchen extensions, bungalows with flat-roofed side extensions and dormers and 1960s and 1970s link-detached houses with flat-roofed garages and porches. 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 Hampshire the application goes to Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 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.

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 Hampshire do we cover?

Mastic asphalt roofing in Hampshire: questions

Which towns in Hampshire do you cover?

All of Hampshire. 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 Hampshire?

£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 Hampshire?

It depends on where the roof is: in Hampshire that's Southampton City Council, Portsmouth City Council, Basingstoke and Deane Borough Council and 10 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.

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.

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.

Everything about mastic asphalt roofing → · All flat roofing in Hampshire →

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