Two-storey rear extensions in Glasgow and Dunbartonshire

Glasgow and Dunbartonshire at a glance

Nation: Scotland
Price region: Scotland
Postcode areas: G
Towns covered: 19 listed below, plus surrounding villages
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.
Site visits: Free, no obligation

What a two-storey rear extension involves

A two-storey rear extension is a new two-floor addition built onto the back of your house, usually giving a larger kitchen or living space on the ground floor and one or two bedrooms or a bathroom above. Because both floors share one set of foundations and one roof, it adds a lot of floor space for the garden it uses. In some cases it can be built under permitted development, depending on where you live.

Towns in Glasgow and Dunbartonshire include Glasgow (G1), Bearsden (G13), Newton Mearns (G77), Clydebank (G81), Vale of Leven (G82) and Bishopbriggs (G22). If yours isn't listed, we still cover it.

Guide price in Scotland

In Scotland, which includes Glasgow and Dunbartonshire, we'd expect a two-storey rear extension to cost around £52,500–£71,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), or £1,880–£2,540 per m² including VAT. Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	Typical project
Essential	£1,730–£2,330 per m²	£48,500–£65,500
Standard	£1,880–£2,540 per m²	£52,500–£71,000
Premium	£2,260–£3,050 per m²	£63,000–£85,500

Rules in Scotland

In Scotland, a two-storey rear extension is only permitted development under Class 1B if no part of it is within 10 m of any boundary, it is no higher than the house and the house is not in a conservation area. Most gardens cannot meet the 10 m test, so expect 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.

There is no Party Wall Act in Scotland. Shared walls and boundaries are governed by title deeds and common law, so we speak to neighbours early and record the condition of shared structures.

Getting the design right

Opening up the ground floor

Knocking through the old rear wall means steel beams to carry the first floor and roof above. The structural engineer sets the beam sizes, padstones and any posts, and we plan them early so the open-plan layout you want is the one that gets built.

Foundations and drains

Foundations for two storeys carry more load than a single storey and may need to go deeper near trees or on clay. Rear extensions often sit near drains, so we check sewer records early, as building over or near a public sewer may need the water company's agreement.

How we work in Glasgow and Dunbartonshire

Understand the brief
At your home in Glasgow and Dunbartonshire we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Scotland before drawing in detail.
Technical design
We prepare the building warrant drawings, structural calculations and specification so the build price can be fixed.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Towns we cover in Glasgow and Dunbartonshire

Two-storey rear extensions in Glasgow and Dunbartonshire: questions

How much does a two-storey rear extension cost in Glasgow and Dunbartonshire?

In Scotland our guide is £1,880–£2,540 per m² including VAT, so about £52,500–£71,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Will a two-storey rear extension block my neighbour's light?

It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.

Will I need planning permission in Glasgow and Dunbartonshire?

Glasgow and Dunbartonshire 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.

Neighbouring areas

All extension services in Glasgow and Dunbartonshire · About two-storey rear extensions