Bushey at a glance
- Postcode districts
- WD1, WD23
- Population
- about 28,416 (GeoNames)
- Council area
- Hertsmere Borough Council
- Building approval
- Hertsmere Borough Council building control, or a registered building control approver
- Nearest main town
- Watford, about 2 miles
- Guide price region
- East of England (+5% on West Midlands rates)
What makes a good extension roof in Bushey?
Extension roofs in Bushey 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.
Bushey's flat roofs are mostly on 1960s and 1970s link-detached houses with flat-roofed garages and porches, 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 Bushey?
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 |
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 deck, vapour control layer and warm-roof insulation
- Free survey of the roof, abutment and room below
- 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?
- Watford · 2 mi
- Borehamwood · 4 mi
- Rickmansworth · 5 mi
- St Albans · 7 mi
- Hemel Hempstead · 9 mi
- Potters Bar · 9 mi
Extension and kitchen roofs in Bushey: questions
Do you cover Bushey?
Yes. Bushey is part of our Hertfordshire coverage, including postcode districts WD1, WD23. 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 Bushey?
Where the work needs approval it goes to Hertsmere 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 Bushey?
£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.
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.
How do I know my extension roof needs replacing rather than repairing?
Repeated leaks, a soft deck, wet insulation or widespread cracking point to replacement. A single defect on a dry, sound roof can usually be repaired.