Two-storey extensions for semi-detached houses in Motherwell

The basics for Motherwell at a glance.

Postcode districts: ML1
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: Mossend (1.9 miles), Bellshill (2.1 miles), Hamilton (2.2 miles)
Distance to East Kilbride: about 7.4 miles
First visit: Free, no obligation

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

This service suits you if you own a semi-detached house and want to add bedrooms and living space without moving. On a semi, the main questions are which side to build on and how to treat the attached neighbour. You get a survey, design options, the approvals your nation needs and the build, carried out by vetted teams working under S&K.

We cover Motherwell (ML1) and the places around it, including Mossend (1.9 miles), Bellshill (2.1 miles) and Hamilton.

What it costs in Motherwell

In Scotland, which includes Motherwell, we'd expect a two-storey extension for a semi-detached house 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. Professional fees for drawings and the structural engineer are listed separately on our prices page.

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 Motherwell

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 Motherwell 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.

Keeping the pair balanced

Semis are designed as matching pairs, and a side extension changes that balance. Setting the side extension back from the front wall and keeping its ridge lower helps the pair still read as a pair, which councils' design guides commonly ask for.

How we'd run your project

Understand the brief
At your home in Motherwell 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 Motherwell and deal with any questions from the planning officer.
Structure and building standards
A structural engineer sizes the foundations and steels, and we get a building warrant before work starts.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about two-storey extensions for semi-detached houses in Motherwell

Do I need planning permission for a two-storey extension for a semi-detached house in Motherwell?

Motherwell 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.

Who handles building standards for a project in Motherwell?

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.

Which postcodes do you cover around Motherwell?

We cover Motherwell (ML1) and nearby places including Mossend, Bellshill and Hamilton, plus the rest of Lanarkshire. The first site visit is free.

Will a side extension make my semi look like a terrace?

It can if it fills the whole gap to the boundary at first floor and the neighbour does the same. Many councils ask for a first-floor gap to the side boundary or a set-back for this reason. We design the extension to keep the semi reading as one of a pair.

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.

Nearby

Close to Motherwell? We work across the area, including:

Other extensions in Motherwell

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

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Motherwell.