First-floor extensions in Weston-super-Mare
Thinking about a first-floor extension in Weston-super-Mare? We design it, take it through the approvals it needs and build it, with one team responsible from the first visit to the final certificate.
Before you start in Weston-super-Mare, here's what applies.
- Postcode districts
- BS22, BS23, BS24 and BS29
- County / area
- Somerset, England
- Price region
- South West England
- Guide price
- £26,000–£37,500 (£1,850–£2,680 per m²)
- Approval route
- It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
- Nearest towns
- Yatton (7.2 miles), Burnham-on-Sea (7.5 miles), Clevedon (8.4 miles)
- Distance to Bath
- about 26.6 miles
- First visit
- Free, no obligation
About a first-floor extension
A first-floor extension suits you if your house already has a single-storey extension and you need more space upstairs. You get a structural check of the existing walls and foundations, a design that ties the new floor into the house, the approvals your nation needs, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.
We cover Weston-super-Mare (BS22, BS23, BS24 and BS29) and the places around it, including Yatton (7.2 miles), Burnham-on-Sea (7.5 miles) and Clevedon.
What it costs in Weston-super-Mare
Most of the cost of a first-floor extension is set by its size and specification. For Weston-super-Mare and the rest of South West England, our guide is £1,850–£2,680 per m² including VAT, so about £26,000–£37,500 for 4 m × 3.5 m of new first-floor space (14 m²). We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.
| Spec | Per m² | 4 m × 3.5 m of new first-floor space (14 m²) |
|---|---|---|
| Essential | £1,710–£2,460 per m² | £24,000–£34,500 |
| Standard | £1,850–£2,680 per m² | £26,000–£37,500 |
| Premium | £2,220–£3,210 per m² | £31,000–£45,000 |
Planning and building regulations in Weston-super-Mare
In England, adding a first floor turns a single-storey extension into one of more than one storey. To be permitted development, the extension as a whole must go no more than 3 m beyond the rear wall of the original house and stay at least 7 m from the rear boundary, with matching materials and roof pitch. Over a side extension it always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026).
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Weston-super-Mare homes
Matching the roofline
A first-floor extension often changes how the back or side of the house looks more than the original single storey did. Matching the main roof pitch and materials, and keeping the ridge below the main ridge, usually gives the best result and is expected for permitted development in England.
Tying into the house
The new floor and walls must line up with the existing first floor, often through a new opening in the rear wall above the old one. Floor levels, the position of upstairs windows and the existing roof all affect where the opening can go, so we survey both floors carefully.
How we'd run your project
Look at the house
We start in Weston-super-Mare with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about first-floor extensions in Weston-super-Mare
Who handles building regulations for a project in Weston-super-Mare?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Do I need planning permission for a first-floor extension in Weston-super-Mare?
Weston-super-Mare is in England, so England planning rules apply. It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Which postcodes do you cover around Weston-super-Mare?
We cover Weston-super-Mare (BS22, BS23, BS24 and BS29) and nearby places including Yatton, Burnham-on-Sea and Clevedon, plus the rest of Somerset. The first site visit is free.
Can I build on top of my existing single-storey extension?
Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.
What happens to the room below while the first floor is built?
The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.
Nearby
Close to Weston-super-Mare? We work across the area, including:
Other extensions in Weston-super-Mare
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Weston-super-Mare · First-floor extensions across Somerset
Want a figure first? Try our guide price tool, then book a free visit to firm it up.