Preston at a glance
- Postcode districts
- PR1, PR2
- Population
- about 313,332 (GeoNames)
- Council area
- Preston City Council
- Building approval
- Preston City Council building control, or a registered building control approver
- Guide price region
- North West (−5% on West Midlands rates)
Why upgrade to a warm roof in Preston?
Converting a garage, loft space or outbuilding to a room in Preston changes what the roof needs to do. Once the space is heated, the roof is expected to perform to a higher standard, and a warm build-up is usually the simplest way to get there.
In and around Preston, flat roofs are typically found on newer estates where the first extension roofs are now being replaced, and on 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.
How much does a warm roof upgrade cost in Preston?
At North West guide rates, a 20 m² extension roof in EPDM with a new deck and insulation comes to £2,650–£4,650 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 | £2,650–£4,650 |
| Extension (20 m²), EPDM with sedum green roof | £4,200–£7,700 |
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.
What's included?
- Building control or building standards handled where needed
- Survey of the deck, joists and existing insulation
- Vapour control layer on the warm side of the insulation
- Upstands, trims and kerbs reset to the new roof level
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?
- Leyland · 5 mi
- Chorley · 9 mi
- Blackburn · 9 mi
- Darwen · 11 mi
- Lytham St Annes · 12 mi
- Poulton-le-Fylde · 12 mi
Warm roof insulation upgrades in Preston: questions
Do you cover Preston?
Yes. Preston is part of our Lancashire coverage, including postcode districts PR1, PR2. 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 Preston?
Where the work needs approval it goes to Preston City 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 warm roof upgrade cost in Preston?
£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.
Is a warm roof worth it on a garage?
On a detached, unheated garage, usually not, as there is no heated space to protect and the thermal rules don't normally apply. On an integral or heated garage, or one being converted into a room, it is.
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.