Two-storey extensions for semi-detached houses in Stornoway
Homes in Stornoway with a bit of space to the side or rear can often take a two-storey extension for a semi-detached house. We'll tell you honestly whether yours can, and what approvals it needs.
Stornoway is outside our usual mainland visit area, so visits and projects here are by arrangement. We'll agree any travel costs with you before anything is booked.
Stornoway: the key facts for this kind of project.
- Postcode districts
- HS1 and HS2
- County / area
- The Highlands, Moray and Islands, 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
- Dingwall (83.5 miles), Alness (85.8 miles), Invergordon (89 miles)
- Distance to Inverness
- about 94.2 miles
- First visit
- By arrangement
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.
We cover Stornoway (HS1 and HS2) and the places around it, including Dingwall (83.5 miles), Alness (85.8 miles) and Invergordon.
What it costs in Stornoway
Our guide for Scotland is £1,880–£2,540 per m² including VAT. On a project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), that puts a two-storey extension for a semi-detached house in Stornoway at roughly £52,500–£71,000. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| 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 Stornoway
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 Stornoway 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
Visit by arrangement
We agree a visit to your home in Stornoway and any travel costs with you in writing first, then look at the structure, access and boundaries.
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.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
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 Stornoway
Which postcodes do you cover around Stornoway?
We cover Stornoway (HS1 and HS2) and nearby places including Dingwall, Alness and Invergordon, plus the rest of the Highlands, Moray and Islands. Visits and projects in Stornoway are by arrangement, with travel costs agreed in writing first.
Do I need planning permission for a two-storey extension for a semi-detached house in Stornoway?
Stornoway 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.
How much does a two-storey extension for a semi-detached house cost in Stornoway?
Our guide for Scotland, which covers Stornoway, 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.
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.
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
Nearby towns we cover for two-storey extensions for semi-detached houses:
Other extensions in Stornoway
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Stornoway · Two-storey extensions for semi-detached houses across the Highlands, Moray and Islands
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.