South Yorkshire
Flat-roof rear extensions in South Yorkshire
Warm flat roofs with lanterns, parapets and long-life membranes. We design and build rear extensions across South Yorkshire, from Sheffield and Rotherham to Doncaster, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.
Flat roofs are the usual choice for rear extensions because they stay below first-floor windows and take a lantern neatly. Stone terraces and brick semis are typical of South Yorkshire. Matching sandstone or gritstone on a terrace is one of the biggest cost variables, and reclaimed stone is often the best match.
How much does a flat-roof rear extension cost in South Yorkshire?
Guide prices for a flat-roof rear extension in South Yorkshire start from our Yorkshire and the Humber rate of £1,770–£2,880 per square metre, including VAT. Yorkshire prices sit below our West Midlands baseline; matching natural stone is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in South Yorkshire?
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part 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 South Yorkshire do we work?
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 South Yorkshire?
We cover 27 towns and districts in South Yorkshire, including Sheffield, Rotherham and Doncaster.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.