- Guide price
- £4,850–£8,900
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Surrey at a glance
- Largest towns
- Woking, Guildford, Esher, Redhill
- Postcode areas
- CR, GU, KT, RH, SM, TW
- Building control
- Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils
- Neighbouring areas
- London · Berkshire · West Sussex · Buckinghamshire
- Guide price region
- South East (+10% on West Midlands rates)
How much does a green roof cost in Surrey?
Guide prices 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 with sedum green roof | £4,850–£8,900 |
| Extension (20 m²), EPDM, new deck + insulation | £3,100–£5,350 |
Which flat roofs are common in Surrey?
Flat roofs in Surrey sit on 1930s semis with flat-roofed garages and kitchen extensions, newer estates where the first extension roofs are now being replaced and terraced streets with flat-roofed rear kitchens and bathrooms. 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. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Surrey the application goes to Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils. More on the rules.
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.
Can my flat roof take the weight of a green roof?
Not every roof can, which is why we check the structure before quoting. A sedum roof is light compared with an intensive garden, but its growing medium holds water, and a saturated build-up adds significant weight to the roof.
We look at the joist sizes, spans and spacing, the condition of the deck and what the roof sits on. On a recently built extension with generously sized joists, an extensive green roof may be straightforward. On an older garage or a roof with undersized or rotten timbers, the structure may need strengthening, or a structural engineer's calculation may be needed before we can go ahead.
In England, a new roof covering that adds 15% or more to the weight of the roof triggers building control approval, and a green roof will often fall into that category. We handle building control where it is needed. The building regulations page covers the approval routes in each nation.
Which towns in Surrey do we cover?
- Woking
- Guildford
- Esher
- Redhill
- Staines-upon-Thames
- Banstead
- Leatherhead
- Ewell
- Farnham
- Epsom
- Camberley
- Egham
- Sunbury-on-Thames
- Ashford, Surrey
- Godalming
- Reigate
- Horley
- Caterham
- Weybridge
- West Molesey
- Dorking
- Haslemere
- Cobham
- Chertsey
Green and sedum roofs in Surrey: questions
Which towns in Surrey do you cover?
All of Surrey. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a green roof cost in Surrey?
£4,850–£8,900 for a 20 m² insulated extension roof finished as a sedum green roof, at South East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Surrey?
It depends on where the roof is: in Surrey that's Woking Borough Council, Guildford Borough Council, Elmbridge Borough Council and 8 other councils. Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. We confirm which applies at the survey.
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.
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.
Everything about green and sedum roofs → · All flat roofing in Surrey →