Carlisle at a glance
- Postcode districts
- CA1, CA2, CA3
- Population
- about 78,470 (GeoNames)
- Council area
- Cumberland Council
- Building approval
- Cumberland Council building control, or a registered building control approver
- Guide price region
- North West (−5% on West Midlands rates)
Why choose a green roof in Carlisle?
Rainwater from flat roofs in Carlisle runs off quickly in heavy showers. A green roof holds some of that water back and releases it more slowly, which is one reason some owners and developers choose one. The flowering sedum also draws in bees and other insects.
Carlisle's flat roofs are mostly on terraced streets with flat-roofed rear kitchens and bathrooms, 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 green roof cost in Carlisle?
Guide price in Carlisle: £4,200–£7,700 for a 20 m² insulated extension roof finished as a sedum green roof, 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 with sedum green roof | £4,200–£7,700 |
| Extension (20 m²), EPDM, new deck + insulation | £2,650–£4,650 |
How is a green roof built on top of a flat roof?
From the bottom up, a green roof is a deck, a waterproofing system with root protection, then drainage, filter, growing medium and plants. The waterproofing does the job of keeping water out. The green layers sit above it.
- Warm roof build-up: vapour control layer, insulation and waterproof membrane on the deck, then the green layers on top. This is the usual choice on a home extension being re-roofed.
- Inverted build-up: waterproofing on the deck, then insulation boards designed to sit above it, then the green layers. This is common on terraces and some commercial roofs.
- Root barrier: roots will exploit any weakness, so the membrane needs to be root-resistant. Some membranes are tested as root-resistant; others need a separate root barrier laid on top.
- Drainage and edges: a drainage layer carries surplus water to outlets, and a gravel or pebble strip is usually left around edges, outlets, upstands and rooflights to keep them clear and accessible.
Upstands still need to rise around 150 mm above the finished surface, which on a green roof means above the top of the growing medium. We check that at the survey, alongside the external fire performance of the build-up where the roof is close to a boundary.
What's included?
- Drainage layer, filter and lightweight growing medium
- Warm or inverted build-up to suit the roof
- Structural check of joists, deck and supports
- 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 Carlisle: questions
Do you cover Carlisle?
Yes. Carlisle is part of our Cumbria coverage, including postcode districts CA1, CA2, CA3. 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 Carlisle?
Where the work needs approval it goes to Cumberland 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 Carlisle?
£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.
Can a green roof have a rooflight in it?
Yes. The rooflight sits on a raised upstand with a gravel strip around it, so the planting stays clear of the glazing and the upstand stays visible and dry.
Can I walk on a green roof?
Only for maintenance, and only where it is safe. Most extensive green roofs on homes aren't designed as roof terraces, and a terrace generally needs planning permission and edge protection.