Part single, part two-storey extensions in Castle Douglas

Useful details for planning a part single, part two-storey extension in Castle Douglas.

Postcode districts: DG7
County / area: Dumfries and Galloway, Scotland
Price region: Scotland
Guide price: £67,500–£93,000 (£1,880–£2,580 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: Dalbeattie (4.2 miles), Kirkcudbright (8.6 miles), Dumfries (15.4 miles)
Distance to Dumfries: about 15.4 miles
First visit: Free, no obligation

About a part single, part two-storey extension

A part single, part two-storey extension suits you if you want a generous ground floor but only need one extra room upstairs, or if a full two-storey design would affect a neighbour too much. You get design options that test where the two-storey part works best, the approvals your nation needs, structural design, a building warrant and the build, carried out by vetted teams working under S&K.

Around Castle Douglas we also work in Dalbeattie, Kirkcudbright and Dumfries, and across the rest of Dumfries and Galloway. Postcode district in and near Castle Douglas: DG7.

What it costs in Castle Douglas

Most of the cost of a part single, part two-storey extension is set by its size and specification. For Castle Douglas and the rest of Scotland, our guide is £1,880–£2,580 per m² including VAT, so about £67,500–£93,000 for a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total). Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	A 6 m × 4 m ground floor and a first floor over half of it (36 m² in total)
Essential	£1,730–£2,380 per m²	£62,500–£85,500
Standard	£1,880–£2,580 per m²	£67,500–£93,000
Premium	£2,260–£3,100 per m²	£81,000–£111,500

Planning and building standards in Castle Douglas

In Scotland, because part of the extension is more than one storey, it is assessed under Class 1B, which needs at least 10 m to every boundary for permitted development. On most plots that is not possible, so the extension needs a householder application (£371, decided within two months). A building warrant is also needed before any 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.

Design points for Castle Douglas homes

Where to put the two-storey part

The two-storey section usually works best away from the closest neighbour, with the single-storey part on that boundary side. We test a few positions against neighbours' windows, the upstairs layout and the roof shape before choosing the one to take forward.

The roof junction

Where the single-storey roof meets the two-storey wall you need a sound weathering detail, usually a lead or similar flashing, and enough height for roof lights or a lantern. We set the roof falls and the upstairs window sill heights together so they do not clash.

How we'd run your project

Measure and listen
A visit to Castle Douglas to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Castle Douglas and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and a building warrant, all before anyone starts on site.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about part single, part two-storey extensions in Castle Douglas

Which postcodes do you cover around Castle Douglas?

We cover Castle Douglas (DG7) and nearby places including Dalbeattie, Kirkcudbright and Dumfries, plus the rest of Dumfries and Galloway. The first site visit is free.

Who handles building standards for a project in Castle Douglas?

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.

How much does a part single, part two-storey extension cost in Castle Douglas?

Our guide for Scotland, which covers Castle Douglas, is £1,880–£2,580 per m² including VAT. A typical project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) comes to about £67,500–£93,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which side should the two-storey part go on?

Usually the side furthest from the nearest neighbour's windows, so the single-storey part sits nearest them and keeps their light. Other factors are where the stairs land upstairs, which room needs the extra space and where drains run. We sketch options at the design stage and explain which is most likely to be approved.

Can the single-storey part be deeper than the two-storey part?

With planning permission, yes, and that is often the point of the design: the ground floor projects further into the garden while the first floor stays back from neighbours. Under permitted development, the depth limits for extensions of more than one storey can apply to the whole extension, so we confirm which route applies before drawings are finalised.

Nearby

Nearby towns we cover for part single, part two-storey extensions:

Other extensions in Castle Douglas

All two-storey extension services in Castle Douglas · Part single, part two-storey extensions across Dumfries and Galloway

Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.