Brighton at a glance
- Postcode districts
- BN1, BN2, BN3, BN41
- Population
- about 283,870 (GeoNames)
- Council area
- Brighton & Hove City Council
- Building approval
- Brighton & Hove City Council building control, or a registered building control approver
- Guide price region
- South East (+10% on West Midlands rates)
What makes a good extension roof in Brighton?
Selling a house in Brighton with a tired extension roof can raise questions in the buyer's survey. A recent replacement, with building control sign-off where needed and written guarantees, gives a buyer confidence and removes a likely point of negotiation.
In and around Brighton, flat roofs are typically found on 1960s and 1970s link-detached houses with flat-roofed garages and porches, and on lock-up garage blocks on estates. 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 new extension roof cost in Brighton?
At South East guide rates, a 20 m² extension roof in EPDM with a new deck and insulation comes to £3,100–£5,350 including VAT. 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 |
| Extension (20 m²), GRP, new deck + insulation | £3,300–£5,900 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £3,300–£5,750 |
| Single garage (18 m²), EPDM rubber | £1,750–£3,100 |
Which flat roof system suits a kitchen extension?
On a plain rectangular extension, EPDM rubber is a strong, quiet choice that can often be laid in one sheet. It handles the slight movement between an extension and the house well.
Where the roof has a lantern, several rooflights or an internal corner, GRP fibreglass forms neat, rigid details around each one. Torch-on felt is a proven layered system and keeps costs down, though near timber cladding or at fragile junctions we may prefer a cold-applied method. If the extension is overlooked from upstairs windows, a sedum green roof is worth considering, provided the structure can take the extra load.
Whatever the membrane, the insulation sits above the deck as a warm roof. Our warm vs cold roof guide explains why.
What's included?
- Falls set away from the house wall
- Building control handled where needed, and a written workmanship guarantee
- New deck, vapour control layer and warm-roof insulation
- New abutment upstand and flashing, plus rebuilt rooflight kerbs
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?
Extension and kitchen roofs in Brighton: questions
Do you cover Brighton?
Yes. Brighton is part of our East Sussex coverage, including postcode districts BN1, BN2, BN3, BN41. 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 Brighton?
Where the work needs approval it goes to Brighton & Hove City 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 new extension roof cost in Brighton?
£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.
Can a sedum roof go on my extension?
Possibly, if the structure can carry the extra weight and the roof has suitable falls and drainage. We check the joists at survey before recommending it.
Do I need my neighbour's permission to replace an extension roof?
Not for a like-for-like re-cover in most cases. The Party Wall Act in England and Wales can apply if the work raises or cuts into a shared wall, so we flag that at survey.