- Guide price
- £2,650–£4,650
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Merseyside at a glance
- Largest towns
- Liverpool, Birkenhead, St Helens, Southport
- Postcode areas
- CH, L, PR, WA
- Building control
- Liverpool City Council, Wirral Council, St Helens Borough Council and 2 other councils
- Neighbouring areas
- Cheshire · Greater Manchester · Lancashire · Shropshire
- Guide price region
- North West (−5% on West Midlands rates)
How much does a warm roof upgrade cost in Merseyside?
Guide prices including VAT at North West 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 | £2,650–£4,650 |
| Extension (20 m²), EPDM with sedum green roof | £4,200–£7,700 |
Which flat roofs are common in Merseyside?
Flat roofs in Merseyside sit on shops with flat-roofed rear stores below flats, 1960s and 1970s link-detached houses with flat-roofed garages and porches and terraced streets with flat-roofed rear kitchens and bathrooms. The North West is one of England's wetter regions, averaging roughly 1,290 mm of rain a year, so falls, outlets and well-detailed upstands matter more than the membrane colour. 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 Merseyside the application goes to Liverpool City Council, Wirral Council, St Helens Borough Council and 2 other councils. More on the rules.
How long does a warm roof last?
The insulation in a warm roof should last for the life of the waterproofing above it, as long as it stays dry. Rigid PIR boards don't settle or slump in the way some loose insulation can.
The waterproofing is what sets the timescale. EPDM is typically quoted at 25 to 50 years, GRP at 20 to 40 years and modern torch-on felt at 15 to 25 years with good specification and care. A warm build-up also helps the deck, because keeping it warm and dry lowers the risk of condensation rot. If the waterproofing fails and water gets into the insulation, the wet boards should be replaced, so leaks need prompt attention. The lifespan guide compares the systems.
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 Merseyside do we cover?
- Liverpool
- Birkenhead
- St Helens
- Southport
- Wallasey
- Bootle
- Bebington
- Huyton
- Kirkby
- Prescot
- Heswall
- Maghull
- Newton-le-Willows
- Formby
- Garston
- Speke
- Norris Green
- Kirkdale
- Moreton
- Haydock
- Belle Vale
- Old Swan
- Allerton
Warm roof insulation upgrades in Merseyside: questions
Which towns in Merseyside do you cover?
All of Merseyside. 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 Merseyside?
£2,650–£4,650 for a 20 m² extension roof in EPDM with a new deck and insulation, at North West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Merseyside?
It depends on where the roof is: in Merseyside that's Liverpool City Council, Wirral Council, St Helens Borough Council and 2 other councils. 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. We confirm which applies at the survey.
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.
How thick does flat roof insulation need to be?
It depends on the insulation product and the U-value target. With common PIR boards, meeting a renovation target usually means well over 100 mm. Thinner, higher-performance boards are available where height is tight.
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 Merseyside →