First-floor extensions in Glasgow
If you live in Glasgow and need more room without moving, a first-floor extension is worth a serious look. We handle the drawings, approvals, structure and build.
Before you start in Glasgow, here's what applies.
- Postcode districts
- G1, G2, G3, G4, G5, G11 and nearby districts
- County / area
- Glasgow and Dunbartonshire, Scotland
- Price region
- Scotland
- Guide price
- £23,500–£34,000 (£1,690–£2,440 per m²)
- Approval route
- Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
- Nearest towns
- Rutherglen (3 miles), Bishopbriggs (3.2 miles), Stepps (4.4 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, a building warrant and the build, managed by us and carried out by vetted teams working under S&K.
We cover Glasgow (G1, G2, G3, G4, G5, G11 and nearby districts) and the places around it, including Rutherglen (3.0 miles), Bishopbriggs (3.2 miles) and Stepps.
What it costs in Glasgow
Our guide for Scotland is £1,690–£2,440 per m² including VAT. On a project with 4 m × 3.5 m of new first-floor space (14 m²), that puts a first-floor extension in Glasgow at roughly £23,500–£34,000. Keep a contingency of around 10% for things nobody can see until the ground is opened up.
| Spec | Per m² | 4 m × 3.5 m of new first-floor space (14 m²) |
|---|---|---|
| Essential | £1,560–£2,250 per m² | £22,000–£31,500 |
| Standard | £1,690–£2,440 per m² | £23,500–£34,000 |
| Premium | £2,030–£2,930 per m² | £28,500–£41,000 |
Planning and building standards in Glasgow
In Scotland, permitted development for extensions of more than one storey (Class 1B) needs at least 10 m to every boundary and no part higher than the house. Most first-floor extensions cannot meet the 10 m test, so plan for a householder application (£371, decided within two months) and a building warrant before work starts.
Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.
Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.
Design points for Glasgow homes
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.
Escape and fire safety
A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and 450 mm high, with the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs.
How we'd run your project
Free site visit
We visit your home in Glasgow, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Technical design
We prepare the building warrant drawings, structural calculations and specification so the build price can be fixed.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.
Questions about first-floor extensions in Glasgow
Which postcodes do you cover around Glasgow?
We cover Glasgow (G1, G2, G3, G4, G5, G11 and nearby districts) and nearby places including Rutherglen, Bishopbriggs and Stepps, plus the rest of Glasgow and Dunbartonshire. The first site visit is free.
How much does a first-floor extension cost in Glasgow?
Our guide for Scotland, which covers Glasgow, is £1,690–£2,440 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £23,500–£34,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Do I need planning permission for a first-floor extension in Glasgow?
Glasgow is in Scotland. Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
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 a building warrant 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 Glasgow? We work across the area, including:
Other extensions in Glasgow
- 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 Glasgow · First-floor extensions across Glasgow and Dunbartonshire
The quickest next step is a visit. We'll look at your house in Glasgow and give you an honest view of the options.