Sevenoaks at a glance
- Postcode districts
- TN13
- Population
- about 29,506 (GeoNames)
- Council area
- Sevenoaks District Council
- Building approval
- Sevenoaks District Council building control, or a registered building control approver
- Nearest main town
- Maidstone, about 14 miles
- Guide price region
- South East (+10% on West Midlands rates)
What makes a good extension roof in Sevenoaks?
Ponding against the house wall is a common reason for replacing an extension roof in Sevenoaks. When the deck dips near the wall or the fall runs the wrong way, water sits against the abutment and eventually gets in. A new roof with corrected falls moves the water to the gutter.
In and around Sevenoaks, flat roofs are typically found on newer estates where the first extension roofs are now being replaced, and on 1930s semis with flat-roofed garages and kitchen extensions. 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 Sevenoaks?
For Sevenoaks 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 |
| 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 |
How long will my kitchen be disrupted by a new roof?
Most single-storey extension roofs are replaced in two to four working days, depending on size, rooflights and weather. The kitchen usually stays in use throughout.
Expect noise during the strip-out, and occasional dust through gaps around old rooflights, so it helps to cover worktops and move anything fragile off high shelves. We strip only what we can make weathertight by the end of each day. If a rooflight or lantern is being lifted and refitted, there may be a temporary cover over the opening for a short time. Resin systems smell while they cure, so keep the windows below the roof closed on that day.
What's included?
- Staged strip-out so the room stays weathertight
- Falls set away from the house wall
- New deck, vapour control layer and warm-roof insulation
- Building control handled where needed, and a written workmanship guarantee
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?
- Tonbridge · 6 mi
- Swanley · 9 mi
- Longfield · 10 mi
- Royal Tunbridge Wells · 10 mi
- Caterham · 12 mi
- Dartford · 12 mi
Extension and kitchen roofs in Sevenoaks: questions
Do you cover Sevenoaks?
Yes. Sevenoaks is part of our Kent coverage, including postcode districts TN13. 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 Sevenoaks?
Where the work needs approval it goes to Sevenoaks District 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 Sevenoaks?
£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.
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.
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.