First-floor extensions in Sunderland

Useful details for planning a first-floor extension in Sunderland.

Postcode districts: SR1, SR4, SR6 and SR9
County / area: Tyne and Wear, England
Price region: North East England
Guide price: £22,500–£33,000 (£1,620–£2,340 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: Ryhope (2.3 miles), The Boldons (3.9 miles), Seaham (4.8 miles)
Distance to Newcastle upon Tyne: about 10.4 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.

Around Sunderland we also work in Ryhope, The Boldons and Seaham, and across the rest of Tyne and Wear. Postcode districts in and near Sunderland: SR1, SR4, SR6 and SR9.

What it costs in Sunderland

Guide prices for first-floor extensions in North East England are around £1,620–£2,340 per m² of new floor space, including VAT. For a typical project with 4 m × 3.5 m of new first-floor space (14 m²), that's roughly £22,500–£33,000. The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	4 m × 3.5 m of new first-floor space (14 m²)
Essential	£1,490–£2,150 per m²	£21,000–£30,000
Standard	£1,620–£2,340 per m²	£22,500–£33,000
Premium	£1,940–£2,810 per m²	£27,000–£39,500

Planning and building regulations in Sunderland

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 Sunderland homes

Can the existing structure take it?

Many single-storey extensions were built with foundations, walls and lintels sized for one storey. We find out what is there with trial holes and, where available, the original building control drawings. The engineer then decides whether to reuse, strengthen or rebuild parts of the structure.

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

Understand the brief
At your home in Sunderland we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Get it approved
Once you're happy with the design we submit it to the council for Sunderland and deal with any questions from the planning officer.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
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 Sunderland

How much does a first-floor extension cost in Sunderland?

Our guide for North East England, which covers Sunderland, is £1,620–£2,340 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £22,500–£33,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

How long does a first-floor extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

Do I need planning permission for a first-floor extension in Sunderland?

Sunderland 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.

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 Sunderland? We work across the area, including:

Other extensions in Sunderland

All two-storey extension services in Sunderland · First-floor extensions across Tyne and Wear

The quickest next step is a visit. We'll look at your house in Sunderland and give you an honest view of the options.