Portslade at a glance
- Postcode districts
- BN41
- Population
- about 20,000 (GeoNames)
- Council area
- Brighton & Hove City Council
- Building approval
- Brighton & Hove City Council building control, or a registered building control approver
- Nearest main town
- Brighton, about 3 miles
- Guide price region
- South East (+10% on West Midlands rates)
Why upgrade to a warm roof in Portslade?
Kitchen extensions in Portslade, as elsewhere, produce a lot of moisture from cooking. Under a cold flat roof, that moisture can condense on the deck. A warm roof keeps the deck warm and puts a vapour control layer in the way, which lowers the risk considerably.
In a town like Portslade, flat roofs are commonly found on lock-up garage blocks on estates or 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.
How much does a warm roof upgrade cost in Portslade?
Guide price in Portslade: £3,100–£5,350 for a 20 m² extension roof in EPDM with a new deck and insulation, 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 |
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?
- New waterproofing, with a written workmanship guarantee
- Rigid insulation boards sized to the U-value target
- Survey of the deck, joists and existing 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?
- Shoreham-by-Sea · 3 mi
- Brighton · 3 mi
- Lancing · 5 mi
- Worthing · 7 mi
- Rottingdean · 7 mi
- Burgess Hill · 9 mi
Warm roof insulation upgrades in Portslade: questions
Do you cover Portslade?
Yes. Portslade is part of our East Sussex coverage, including postcode districts BN41. 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 Portslade?
Where the work needs approval it goes to Brighton & Hove 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 Portslade?
£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.
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.