Hammersmith and Fulham at a glance
- Postcode districts
- W6, W14, W12, SW6, SW13, W4, SW14
- Council area
- London Borough of Hammersmith and Fulham
- Building approval
- London Borough of Hammersmith and Fulham building control, or a registered building control approver
- Guide price region
- London (+20% on West Midlands rates)
Why choose a green roof in Hammersmith and Fulham?
In a place like Hammersmith and Fulham, many people look out over a flat extension or garage roof from upstairs. Grey felt or rubber isn't much of a view, and a sedum roof turns it into something green that changes colour through the seasons and flowers in summer.
In and around Hammersmith and Fulham, flat roofs are typically found on mansard and dormer loft conversions, and on kitchen extensions and roof terraces behind period houses. The Thames basin is one of the drier parts of Britain at roughly 730 mm of rain a year, but summer heat is the bigger test here: dark membranes on south-facing roofs swing a long way in temperature.
How much does a green roof cost in Hammersmith and Fulham?
At London guide rates, a 20 m² insulated extension roof finished as a sedum green roof comes to £5,300–£9,700 including VAT. 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 | £5,300–£9,700 |
| Extension (20 m²), EPDM, new deck + insulation | £3,350–£5,850 |
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?
- Warm or inverted build-up to suit the roof
- Root-resistant membrane or separate root barrier
- Gravel strips kept clear around edges and outlets
- 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?
- Kensington and Chelsea · 1 mi
- Wandsworth · 3 mi
- Westminster · 3 mi
- Ealing · 4 mi
- Camden · 4 mi
- Lambeth · 5 mi
Green and sedum roofs in Hammersmith and Fulham: questions
Do you cover Hammersmith and Fulham?
Yes. Hammersmith and Fulham is part of our London coverage, including postcode districts W6, W14, W12, SW6, SW13, W4 and 1 more. 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 Hammersmith and Fulham?
Where the work needs approval it goes to London Borough of Hammersmith and Fulham 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 Hammersmith and Fulham?
£5,300–£9,700 for a 20 m² insulated extension roof finished as a sedum green roof, at London guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Can you put a green roof on a pitched roof?
We install green roofs on flat roofs only. Sloping green roofs need extra restraint to stop the growing medium slipping, and they are a specialist job outside our work.
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.