Flat roofing questions answered

As a guide, re-covering an 18 m² single garage roof costs around £1,500–£2,600 in torch-on felt or £1,600–£2,800 in EPDM, including VAT. A 20 m² extension roof with a new deck and warm-roof insulation is around £2,800–£4,900 in EPDM. These are guide prices, and the fixed price comes after the free survey.

A localised patch repair is typically £150–£500, and an upstand, flashing or abutment repair £250–£650. An emergency temporary-weatherproofing visit is around £180–£450, and the fixed price for any permanent repair is confirmed once the roof has been inspected.

Yes, for replacement and new roofs the survey and fixed written quote are free, with no obligation to go ahead. A condition survey with a written report, or a leak investigation, is a paid service, guide £150–£300.

Roof size, the system chosen and the condition of the deck make the biggest difference. Insulation, access and scaffold, upstands, rooflights and outlets, height, waste disposal and region also affect the price. Small roofs cost more per square metre because set-up costs are spread over less area, and the minimum charge for a full re-roof is £750–£1,250.

Yes, the guide prices on this site include VAT at 20%. Flat roof repair and replacement is standard-rated, and insulation fitted as part of a roof replacement is usually not split out at a lower rate, so we don't promise any VAT relief.

No single system is best for every roof. EPDM suits simple roofs and has a long life, GRP suits roofs with complex details or occasional foot traffic, and modern torch-on felt is robust and good value. With good specification and maintenance, indicative lives are 25–50 years for EPDM, 20–40 for GRP and 15–25 for torch-on felt.

A flat roof typically lasts anywhere from 10 to 60 years, depending on the system: torch-on felt 15–25, liquid-applied 10–25+, GRP 20–40, single-ply 25–35+, EPDM 25–50 and mastic asphalt 30–60. Good falls, careful detailing and regular maintenance matter as much as the material.

A warm roof is the preferred choice for most flat roofs over heated rooms, with insulation above the deck, below the waterproofing and over a vapour control layer. A cold roof puts the insulation between the joists and needs ventilation to manage condensation, and industry guidance advises avoiding it where possible.

Sometimes, if the existing roof is sound, dry and firmly bonded, an overlay can work. Wet insulation, a soft deck or several old layers mean a full strip-out is the better long-term answer, and the survey checks for these.

Only if it is designed for it, as most garage and extension roofs are built for maintenance access only. A roof terrace needs a structure that can take the load, a walking surface, guarding and usually planning permission.

Usually not, if the roof's appearance does not change materially. Listed buildings need listed building consent for changes that affect their character, some conservation areas have Article 4 directions, and a new roof terrace or balcony generally needs planning permission.

Often, yes. In England, Wales and Northern Ireland, re-covering a flat roof over heated rooms is usually renovation of a thermal element, and if more than half the roof is renovated the insulation should be upgraded where feasible, which normally needs approval. We handle building control where it is needed.

Usually yes, if the roof is over heated rooms and you are replacing more than half of it. In England the renovation target for a domestic roof is a U-value of 0.16 W/m²K, applied where technically, functionally and economically feasible, while an unheated detached garage normally does not need upgrading.

Yes. Scotland uses Section 6 of the building standards technical handbooks, with a roof benchmark of 0.12 W/m²K for homes pursued as far as reasonably practicable. Check with the council's building standards service whether a building warrant is needed: like-for-like covering repairs can be exempt, but alterations and structural work usually need one.

Not usually, because re-covering a roof does not normally trigger the Party Wall etc. Act 1996, which applies in England and Wales only. Raising or cutting into a party wall can, so we flag it at survey stage if the design affects a shared wall.

A typical garage or extension roof usually takes one to four days, depending on its size, the condition of the deck and the weather. Larger and commercial roofs take longer and are planned in phases.

The team only strips as much roof as can be made watertight before leaving site, and keeps temporary covers ready. GRP and liquid systems need dry conditions and suitable temperatures to cure, so work may be moved to a better day.

The strip-out is the noisiest and messiest stage, and waste is removed in a skip or bags, shown as a line in your quote. Torch-on felt uses a gas torch, so fire precautions are taken, and flame-free systems are available where needed.

Work stops on that area until it has been dealt with, because we don't remove asbestos ourselves. A licensed specialist surveys and removes it before our work starts or continues.

Every job is planned under the Construction (Design and Management) Regulations 2015, or CDM (NI) 2016 in Northern Ireland, and on domestic work the contractor takes on the client's duties. Roofs are treated as fragile until a competent person confirms otherwise, and edge protection goes up on every job.

Every re-roof comes with a written workmanship guarantee, with its length set out in your quote. Manufacturer material guarantees are available on many systems and are registered for you where the system allows, and you can ask about insurance-backed guarantee options.

No, a BBA certificate assesses a product, but it is not a guarantee. Manufacturer material guarantees, contractor workmanship guarantees and insurance-backed guarantees are three separate documents, and manufacturer guarantees often need registration, a specified build-up and sometimes an approved installer.

Payment terms are set out in your written quote. The quote also shows what is included, the system and build-up, and the guarantees that apply, so you can check everything before agreeing to go ahead.

Contact us using the details on your quote or guarantee paperwork, and we will arrange for the roof to be inspected. Defects in our workmanship are dealt with under the written workmanship guarantee.

Check it at least once a year and after storms, and keep outlets, gutters and scuppers clear of leaves and debris. Look out for ponding, blisters, cracks, split laps, lifted flashings and loose trims, and have small defects repaired early before water reaches the deck.