West Midlands
Flat-roof rear extensions in the West Midlands
Warm flat roofs with lanterns, parapets and long-life membranes. Across the West Midlands we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Birmingham, Coventry and Wolverhampton.
Flat roofs are the usual choice for rear extensions because they stay below first-floor windows and take a lantern neatly. West Midlands has a lot of post-war semis and estate houses with long gardens and side access, which makes rear extensions quicker to build.
How much does a flat-roof rear extension cost in the West Midlands?
In the West Midlands, our guide for a flat-roof rear extension is £1,900–£3,100 per square metre including VAT for a standard specification. The West Midlands is the baseline for our guide prices.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £23,000–£37,000 |
| 4 m wide × 5 m deep (20 m²) | £38,000–£62,000 |
| 4 m wide × 6 m deep (24 m²) | £45,500–£74,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission in the West Midlands?
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in the West Midlands do we work?
- Birmingham
- Coventry
- Wolverhampton
- Dudley
- Walsall
- Solihull
- Sutton Coldfield
- West Bromwich
- Halesowen
- Stourbridge
- Smethwick
- Willenhall
- Tipton
- Bloxwich
- Wednesfield
- Washwood Heath
- Aston
- Shirley
- Brierley Hill
- Aldridge
- Acocks Green
- Bartley Green
- Wednesbury
- Kingswinford
- Hockley
- Wombourne
- Brownhills
- Chelmsley Wood
- Streetly
- Pelsall
- Oldbury
- Knowle
- Castle Vale
FAQ
Questions people ask
How long does a flat roof last?
A well-built single-ply or GRP warm roof typically lasts 25 years or more.
Is a flat roof really flat?
No; it is built to falls so water drains to outlets or gutters.
Can I walk on it?
Not as a balcony without planning permission and a guarding design; it can be accessed for maintenance.
Do you cover all of the West Midlands?
We cover 33 towns and districts in the West Midlands, including Birmingham, Coventry and Wolverhampton.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.