St Helens at a glance
- Postcode districts
- L35, WA9, WA10, WA11, WA12
- Population
- about 183,200 (GeoNames)
- Council area
- St Helens Borough Council
- Building approval
- St Helens Borough Council building control, or a registered building control approver
- Nearest main town
- Liverpool, about 10 miles
- Guide price region
- North West (−5% on West Midlands rates)
What makes a good extension roof in St Helens?
If you're fitting a new kitchen under an extension in St Helens, that's a good time to replace the roof. It makes sense to rebuild the roof before fitting new units, ceilings and lighting below, and the insulation upgrade makes the room more comfortable all year.
St Helens's flat roofs are mostly on lock-up garage blocks on estates, with plenty on 1960s and 1970s link-detached houses with flat-roofed garages and porches too. 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 new extension roof cost in St Helens?
Guide price in St Helens: £2,650–£4,650 for a 20 m² extension roof in EPDM with a new deck and insulation, 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), GRP, new deck + insulation | £2,850–£5,100 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £2,850–£4,950 |
| Single garage (18 m²), EPDM rubber | £1,500–£2,650 |
How long will my kitchen be disrupted by a new roof?
Most single-storey extension roofs are replaced in two to four working days, depending on size, rooflights and weather. The kitchen usually stays in use throughout.
Expect noise during the strip-out, and occasional dust through gaps around old rooflights, so it helps to cover worktops and move anything fragile off high shelves. We strip only what we can make weathertight by the end of each day. If a rooflight or lantern is being lifted and refitted, there may be a temporary cover over the opening for a short time. Resin systems smell while they cure, so keep the windows below the roof closed on that day.
What's included?
- Building control handled where needed, and a written workmanship guarantee
- Free survey of the roof, abutment and room below
- Staged strip-out so the room stays weathertight
- Falls set away from the house wall
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?
- Haydock · 2 mi
- Prescot · 3 mi
- Ashton in Makerfield · 4 mi
- Huyton · 5 mi
- Newton-le-Willows · 5 mi
- Great Sankey · 6 mi
Extension and kitchen roofs in St Helens: questions
Do you cover St Helens?
Yes. St Helens is part of our Merseyside coverage, including postcode districts L35, WA9, WA10, WA11, WA12. 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 St Helens?
Where the work needs approval it goes to St Helens 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 new extension roof cost in St Helens?
£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.
Why does my extension ceiling get damp in winter if the roof isn't leaking?
That is often condensation in a cold roof, where warm, moist air reaches the cold underside of the deck. A warm-roof replacement with a vapour control layer usually solves it.
Do I need my neighbour's permission to replace an extension roof?
Not for a like-for-like re-cover in most cases. The Party Wall Act in England and Wales can apply if the work raises or cuts into a shared wall, so we flag that at survey.