Watford at a glance
- Postcode districts
- WD1, WD17, WD18, WD19, WD24, WD25
- Population
- about 125,707 (GeoNames)
- Council area
- Watford Borough Council
- Building approval
- Watford Borough Council building control, or a registered building control approver
- Nearest main town
- Slough, about 13 miles
- Guide price region
- East of England (+5% on West Midlands rates)
What makes a good extension roof in Watford?
Selling a house in Watford 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.
Watford's flat roofs are mostly on low-rise post-war blocks of flats, with plenty on lock-up garage blocks on estates too. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof.
How much does a new extension roof cost in Watford?
At East of England guide rates, a 20 m² extension roof in EPDM with a new deck and insulation comes to £2,950–£5,150 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 | £2,950–£5,150 |
| Extension (20 m²), GRP, new deck + insulation | £3,150–£5,650 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £3,150–£5,500 |
| Single garage (18 m²), EPDM rubber | £1,700–£2,950 |
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
- New abutment upstand and flashing, plus rebuilt rooflight kerbs
- Free survey of the roof, abutment and room below
- 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?
- Bushey · 2 mi
- Rickmansworth · 4 mi
- Borehamwood · 5 mi
- St Albans · 7 mi
- Hemel Hempstead · 7 mi
- Chalfont Saint Peter · 8 mi
Extension and kitchen roofs in Watford: questions
Do you cover Watford?
Yes. Watford is part of our Hertfordshire coverage, including postcode districts WD1, WD17, WD18, WD19, WD24, WD25. 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 Watford?
Where the work needs approval it goes to Watford 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 new extension roof cost in Watford?
£2,950–£5,150 for a 20 m² extension roof in EPDM with a new deck and insulation, at East of England 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.
Will a new extension roof sit higher than the old one?
Usually, by the thickness of the added insulation. We check the height against the upstairs window sills, door thresholds and wall flashings at survey so everything still works.