Guildford at a glance
- Postcode districts
- GU1, GU2, GU4
- Population
- about 71,873 (GeoNames)
- Council area
- Guildford Borough Council
- Building approval
- Guildford Borough Council building control, or a registered building control approver
- Nearest main town
- Woking, about 6 miles
- Guide price region
- South East (+10% on West Midlands rates)
When should a flat roof in Guildford be replaced?
Exposure matters too. Wind lifts tired edges, and repeated wetting and drying works at old joints, so roofs in exposed spots can wear faster than the same roof somewhere sheltered. Wherever your property is in Guildford, a survey tells you whether the roof has years left or needs replacing now.
In and around Guildford, flat roofs are typically found on lock-up garage blocks on estates, and on low-rise post-war blocks of flats. 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.
How much does a flat roof replacement cost in Guildford?
For Guildford we use South East rates: £3,100–£5,350 is the guide for a 20 m² extension roof in EPDM with a new deck and insulation, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM, new deck + insulation | £3,100–£5,350 |
| Single garage (18 m²), torch-on felt | £1,650–£2,900 |
| Extension (20 m²), GRP, new deck + insulation | £3,300–£5,900 |
| Single garage (18 m²), EPDM rubber | £1,750–£3,100 |
Do I need building regulations approval to replace a flat roof?
Often, yes. Replacing the covering of a flat roof over a heated room is usually treated as renovating a thermal element, which brings insulation requirements and, in most cases, approval.
In England, if more than half of that roof is renovated, the whole roof should be upgraded towards a U-value of 0.16 W/m²K for homes (0.18 for non-domestic buildings) where that is technically, functionally and economically feasible, judged against a simple payback of 15 years. Approval comes from building control or self-certification through a registered competent person scheme. Structural changes, or a covering that adds 15% or more to the roof's weight, also need approval.
The other nations differ: most re-roofing in Wales needs approval, Scotland works through building standards and the building warrant, and in Northern Ireland you contact the district council's building control first. An unheated detached garage is not normally a thermal element. Planning permission is not usually needed if the roof looks much the same afterwards, though listed buildings and conservation areas are different. We handle approvals where needed; see building regulations.
What's included?
- Free survey of the deck, falls, edges and insulation
- Fixed written quote listing the full build-up
- Strip-out of the old covering, with waste and skip
- New membrane, upstands, edge trims and outlets
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
Flat roof replacement in Guildford: questions
Do you cover Guildford?
Yes. Guildford is part of our Surrey coverage, including postcode districts GU1, GU2, GU4. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Guildford?
Where the work needs approval it goes to Guildford Borough Council building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a flat roof replacement cost in Guildford?
£3,100–£5,350 for a 20 m² extension roof in EPDM with a new deck and insulation, at South East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Is VAT charged on a flat roof replacement?
Yes, roof replacement is standard-rated at 20%, and an insulated replacement is treated as a single supply. Our guide prices already include VAT.
Will a replacement make my roof higher?
Usually a little, if insulation is added above the deck. We check door thresholds, window sills, upstands and wall flashings at survey so the new level works.