Rottingdean at a glance
- Postcode districts
- BN2
- Population
- about 21,756 (GeoNames)
- Council area
- Brighton & Hove City Council
- Building approval
- Brighton & Hove City Council building control, or a registered building control approver
- Nearest main town
- Brighton, about 4 miles
- Guide price region
- South East (+10% on West Midlands rates)
What makes a good extension roof in Rottingdean?
Extension roofs in Rottingdean are often replaced because the original was built cheaply: thin chipboard decks, little or no insulation and felt turned up the wall without a proper flashing. Twenty or thirty years on, those weaknesses show up as leaks at the back wall and a cold, damp ceiling.
In and around Rottingdean, flat roofs are typically found on shops with flat-roofed rear stores below flats, 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 Rottingdean?
Guide price in Rottingdean: £3,100–£5,350 for a 20 m² extension roof in EPDM with a new deck and insulation, including VAT at South East rates. 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?
- New abutment upstand and flashing, plus rebuilt rooflight kerbs
- Building control handled where needed, and a written workmanship guarantee
- Staged strip-out so the room stays weathertight
- Falls set away from the house wall
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 Rottingdean: questions
Do you cover Rottingdean?
Yes. Rottingdean is part of our East Sussex coverage, including postcode districts BN2. 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 Rottingdean?
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 Rottingdean?
£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.
Why does my extension ceiling get damp in winter if the roof isn't leaking?
That is often condensation in a cold roof, where warm, moist air reaches the cold underside of the deck. A warm-roof replacement with a vapour control layer usually solves 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.