- Guide price
- £3,100–£5,350
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Berkshire at a glance
- Largest towns
- Reading, Slough, Bracknell, Maidenhead
- Postcode areas
- GU, RG, SL
- Building control
- Reading Borough Council, Slough Borough Council, Bracknell Forest Council and 3 other councils
- Neighbouring areas
- Surrey · Buckinghamshire · Hampshire · Oxfordshire
- Guide price region
- South East (+10% on West Midlands rates)
How much does a warm roof upgrade cost in Berkshire?
Guide prices 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), EPDM with sedum green roof | £4,850–£8,900 |
Which flat roofs are common in Berkshire?
Flat roofs in Berkshire sit on shops with flat-roofed rear stores below flats, newer estates where the first extension roofs are now being replaced and low-rise post-war blocks of flats. 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. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Berkshire the application goes to Reading Borough Council, Slough Borough Council, Bracknell Forest Council and 3 other councils. More on the rules.
Do I have to insulate my flat roof when I replace it?
Usually, yes, if the roof is over a heated room and you are replacing more than half of its covering. In England, Wales and Northern Ireland, that counts as renovating a thermal element, so the roof should be upgraded to the renovation standard where that is technically, functionally and economically feasible.
The rules don't usually apply to patch repairs, or to an unheated, detached garage. The target U-value depends on where you live:
| Nation | Roof renovation target |
|---|---|
| England | 0.16 W/m²K (homes), 0.18 (non-domestic) |
| Wales | 0.16 W/m²K |
| Scotland | Section 6 framework, with a domestic benchmark of 0.12 W/m²K pursued as far as reasonably practicable |
| Northern Ireland | 0.18 W/m²K |
A new extension roof has a tighter target than a renovation: 0.15 in England and 0.13 in Wales. The economic test in England's guidance is a simple payback within 15 years. We handle building control or building standards where it is needed. The building regulations page sets out the approval routes in each nation.
Can a cold flat roof be converted to a warm roof?
Yes, and it is the usual approach when an older cold roof is re-covered. The old covering is stripped, the deck is checked and replaced where needed, and the vapour control layer, insulation and new waterproofing go on top.
The existing insulation between the joists is assessed at the same time. Leaving it in place can create a cold, unventilated gap that traps moisture, so it is often removed or the build-up is designed so that most of the insulation sits above the deck. We decide this case by case once we can see inside the roof. If the covering is still sound and you are only patching it, the upgrade isn't usually required, and our repair or replace guide explains how to decide between the two.
Which towns in Berkshire do we cover?
Warm roof insulation upgrades in Berkshire: questions
Which towns in Berkshire do you cover?
All of Berkshire. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a warm roof upgrade cost in Berkshire?
£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.
Which postcode areas do you cover in Berkshire?
All of Berkshire, including the GU, RG, SL postcode areas. Send your full postcode and we'll confirm.
Can you add insulation over my existing roof without stripping it?
Sometimes, if the existing covering and deck are dry and sound. We will check at the survey and explain the risks, and our overlay or strip guide covers this choice.
Is there VAT relief on flat roof insulation?
Don't count on it. Insulation fitted as part of a roof replacement is usually treated as part of a single standard-rated job. Check your own case with HMRC guidance or an adviser.
Can you insulate a flat roof from inside instead?
It is possible, but insulating between or under the joists creates a cold roof, which needs ventilation and carries a higher condensation risk. When the roof is being re-covered anyway, a warm roof from above is usually the better option.
Everything about warm roof insulation upgrades → · All flat roofing in Berkshire →