Widnes at a glance
- Postcode districts
- WA8
- Population
- about 61,464 (GeoNames)
- Council area
- Halton Borough Council
- Building approval
- Halton Borough Council building control, or a registered building control approver
- Nearest main town
- St Helens, about 6 miles
- Guide price region
- North West (−5% on West Midlands rates)
Why choose a green roof in Widnes?
Homeowners in Widnes building a new extension may find a green roof can help with a planning application, as some councils encourage them for biodiversity and slower rainwater run-off. It is worth raising early with your designer, before the roof structure is drawn up, so the joists can be sized for the extra weight.
Around Widnes, flat roofs are common on bungalows with flat-roofed side extensions and dormers and on 1960s and 1970s link-detached houses with flat-roofed garages and porches. 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 green roof cost in Widnes?
For Widnes we use North West rates: £4,200–£7,700 is the guide for a 20 m² insulated extension roof finished as a sedum green roof, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £4,200–£7,700 |
| Extension (20 m²), EPDM, new deck + insulation | £2,650–£4,650 |
Can a green roof go on my existing flat roof?
Only if the existing waterproofing is sound, root-resistant or protected by a root barrier, and has plenty of life left. In most cases it makes more sense to lay a green roof as part of a replacement.
Once the sedum, substrate and drainage layers are down, the membrane underneath is hard to inspect and expensive to repair, because the green layers have to be lifted to get to it. Putting a green roof on an ageing covering risks paying for the greenery twice. Our repair or replace guide helps you judge whether your current roof is a sensible base.
As for planning, re-covering a house roof normally needs no application if its appearance doesn't change materially. Because a green roof does change how a roof looks, check with your council, especially for listed buildings, conservation areas and roofs that are easily seen. The planning guide has more.
What's included?
- Warm or inverted build-up to suit the roof
- Drainage layer, filter and lightweight growing medium
- Root-resistant membrane or separate root barrier
- Pre-grown sedum blankets laid and watered in
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?
Green and sedum roofs in Widnes: questions
Do you cover Widnes?
Yes. Widnes is part of our Cheshire coverage, including postcode districts WA8. 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 Widnes?
Where the work needs approval it goes to Halton 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 green roof cost in Widnes?
£4,200–£7,700 for a 20 m² insulated extension roof finished as a sedum green roof, at North West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Do I need to water a sedum roof?
Usually only in the first season, during long dry spells, while the blankets establish. After that, sedum copes with dry weather well.
What happens if a green roof needs repairing?
The green layers are lifted around the problem area, the membrane is repaired, and the layers are relaid. Building on a sound, long-life membrane in the first place keeps that to a minimum.