Two-storey extensions for semi-detached houses in High Blantyre

Useful details for planning a two-storey extension for a semi-detached house in High Blantyre.

Postcode districts: G72
County / area: Lanarkshire, Scotland
Price region: Scotland
Guide price: £52,500–£71,000 (£1,880–£2,540 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: Blantyre (0.9 miles), Bothwell (1.8 miles), Uddingston (2.5 miles)
Distance to East Kilbride: about 3.3 miles
First visit: Free, no obligation

About a two-storey extension for a semi-detached house

A two-storey extension for a semi-detached house is a two-floor addition to the rear, the open side, or both, designed around the attached neighbour on one side. The rear is often the simplest option and can sometimes be permitted development, while a side extension uses the gap on the detached side. Both need care with the shared party wall and the neighbour's light.

Around High Blantyre we also work in Blantyre, Bothwell and Uddingston, and across the rest of Lanarkshire. Postcode district in and near High Blantyre: G72.

What it costs in High Blantyre

Expect a two-storey extension for a semi-detached house in High Blantyre to land somewhere around £52,500–£71,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Our Scotland guide rate is £1,880–£2,540 per m², including VAT. These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
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

Planning and building standards in High Blantyre

In Scotland, Class 1B permitted development needs a two-storey extension to be at least 10 m from every boundary, which a semi-detached house cannot meet on the attached side. In practice a two-storey extension to a semi needs a householder application, which costs £371 and is decided within two months, followed by a building warrant.

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 High Blantyre homes

The attached neighbour's light

A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.

Rear, side or both

On a semi, a rear extension sits against the attached neighbour, while a side extension faces the detached neighbour and the street. We compare the space, cost and approval route for each, and for a wraparound, before you commit to one design.

How we'd run your project

Look at the house
We start in High Blantyre 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 Scotland, then apply for planning permission or a certificate of lawfulness, whichever fits.
Structure and building standards
A structural engineer sizes the foundations and steels, and we get a building warrant before work starts.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about two-storey extensions for semi-detached houses in High Blantyre

Which postcodes do you cover around High Blantyre?

We cover High Blantyre (G72) and nearby places including Blantyre, Bothwell and Uddingston, plus the rest of Lanarkshire. The first site visit is free.

How much does a two-storey extension for a semi-detached house cost in High Blantyre?

Our guide for Scotland, which covers High Blantyre, is £1,880–£2,540 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £52,500–£71,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Who handles building standards for a project in High Blantyre?

We handle it as part of the project. What's needed in Scotland: 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. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

Does a two-storey extension add value to a semi-detached house?

It usually adds value, but the gain is never certain. Nationwide's 2025 research found that 10% more floor area was linked to about 5% higher value, and that adding a double bedroom and bathroom to a three-bed, one-bathroom house could add up to 24%. Every street has a ceiling price, so check local sales first.

What if my neighbour has already extended?

That often helps. An existing extension next door can reduce the effect of yours on their light, and may show what the council accepts on your street. It can also mean building alongside their wall, so we check its position, foundations and any windows facing your plot at the survey.

Nearby

The same service in neighbouring towns:

Other extensions in High Blantyre

All two-storey extension services in High Blantyre · Two-storey extensions for semi-detached houses across Lanarkshire

Tell us about your house in High Blantyre and we'll call you back to arrange a free, no-obligation visit.