Two-storey extensions for semi-detached houses in Isle of Mull
A two-storey extension for a semi-detached house is one of the most space-efficient ways to add bedrooms and living space to a house in Isle of Mull, because the new floors share one set of foundations and one roof.
Isle of Mull 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.
Isle of Mull: the key facts for this kind of project.
- Postcode districts
- PA62, PA63, PA64, PA65, PA71 and PA72
- County / area
- Argyll and Bute, 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
- Isle of Islay (49.1 miles), Oban (11.8 miles), Lochgilphead (31.2 miles)
- Distance to Helensburgh
- about 50.5 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.
Around Isle of Mull we also work in Isle of Islay, Oban and Lochgilphead, and across the rest of Argyll and Bute. Postcode districts in and near Isle of Mull: PA62, PA63, PA64, PA65, PA71 and PA72.
What it costs in Isle of Mull
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 Isle of Mull 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 Isle of Mull
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 Isle of Mull 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 Isle of Mull 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.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Finish and certify
Second fix, plastering and making good, then the council's final building standards inspection and the completion paperwork.
Questions about two-storey extensions for semi-detached houses in Isle of Mull
Who handles building standards for a project in Isle of Mull?
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.
Do I need planning permission for a two-storey extension for a semi-detached house in Isle of Mull?
Isle of Mull 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.
Which postcodes do you cover around Isle of Mull?
We cover Isle of Mull (PA62, PA63, PA64, PA65, PA71 and PA72) and nearby places including Isle of Islay, Oban and Lochgilphead, plus the rest of Argyll and Bute. Visits and projects in Isle of Mull are by arrangement, with travel costs agreed in writing 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.
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.
Nearby
The same service in neighbouring towns:
Other extensions in Isle of Mull
- 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 Isle of Mull · Two-storey extensions for semi-detached houses across Argyll and Bute
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.