Hemel Hempstead at a glance
- Postcode districts
- HP1, HP2, HP3
- Population
- about 95,961 (GeoNames)
- Council area
- Dacorum Borough Council
- Building approval
- Dacorum Borough Council building control, or a registered building control approver
- Nearest main town
- Watford, about 7 miles
- Guide price region
- East of England (+5% on West Midlands rates)
When should a flat roof in Hemel Hempstead be replaced?
A flat roof in Hemel Hempstead is often worth replacing because it is the weak point of the building: heat escapes through an uninsulated deck, rooms below are cold in winter and hot in summer, and condensation marks the ceiling. A warm-roof replacement deals with comfort as well as leaks, so it is worth considering before the roof fails outright.
Hemel Hempstead'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 flat roof replacement cost in Hemel Hempstead?
Guide price in Hemel Hempstead: £2,950–£5,150 for a 20 m² extension roof in EPDM with a new deck and insulation, including VAT at East of England 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 | £2,950–£5,150 |
| Single garage (18 m²), torch-on felt | £1,600–£2,750 |
| Extension (20 m²), GRP, new deck + insulation | £3,150–£5,650 |
| Single garage (18 m²), EPDM rubber | £1,700–£2,950 |
Should I overlay my old flat roof or strip it fully?
Strip it fully if the deck is soft, the insulation is wet or the falls are wrong; an overlay only suits a dry, sound roof that already drains well. Covering a wet roof traps the moisture, and rot carries on out of sight.
An overlay also raises the roof level, eating into upstand height at walls and door thresholds, and every layer adds weight. In England, a covering that adds 15% or more to the roof's weight needs building control approval. Signs it is time to replace rather than repair:
- ponding that lingers long after rain
- blisters, cracking or crazing across wide areas
- bare bitumen where the mineral chippings have gone
- split laps and lifted upstands or flashings
- damp ceilings, or a deck that has gone soft
- leaks that return after each repair
A single defect on an otherwise dry roof can usually be put right with a repair. If you're unsure, a survey settles it, and our guides to overlay or strip and repair or replace go further.
What's included?
- Fixed written quote listing the full build-up
- New membrane, upstands, edge trims and outlets
- Strip-out of the old covering, with waste and skip
- Free survey of the deck, falls, edges and insulation
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?
Flat roof replacement in Hemel Hempstead: questions
Do you cover Hemel Hempstead?
Yes. Hemel Hempstead is part of our Hertfordshire coverage, including postcode districts HP1, HP2, HP3. 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 Hemel Hempstead?
Where the work needs approval it goes to Dacorum 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 flat roof replacement cost in Hemel Hempstead?
£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.
Will a new flat roof be better insulated than the old one?
If it is over a heated room, yes. A full replacement usually has to be upgraded towards current insulation levels where feasible, and we build it as a warm roof with the insulation above the deck.
Is VAT charged on a flat roof replacement?
Yes, roof replacement is standard-rated at 20%, and an insulated replacement is treated as a single supply. Our guide prices already include VAT.