What is a single-storey extension?
A single-storey extension is a ground-floor addition, usually at the rear of a house, that enlarges a kitchen, living or dining space. Most are built with cavity walls on concrete foundations and finished with a flat roof and roof lantern or a pitched tiled roof.
How much does a single-storey extension cost in Kirkwall?
In Kirkwall, a single-storey extension typically costs £1,900–£2,800 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £38,000–£56,000. Island and remote projects usually cost more than this guide because of shipping, travel and accommodation. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £26,500–£39,000 |
| Typical project (20 m²) | £38,000–£56,000 |
| Larger project (28 m²) | £53,000–£78,500 |
| Rate per m² | £1,900–£2,800 |
Your quote will depend mainly on:
- Kitchen, flooring and finishes, which we can include or leave to you
- How much of the existing house is opened up
- Roof type and the size of any lantern or roof windows
- Floor area and the length of new wall
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a single-storey extension in Kirkwall?
The approval route for Kirkwall is set by planning law in Scotland. In Scotland a single-storey extension is often permitted development (Class 1A): where any part is within 1 metre of a boundary, it can project up to 3 metres from the rear wall of a terraced house or 4 metres on other houses, with eaves no higher than 3 metres, an overall height of 4 metres and no more than half the front or rear garden covered. The rights do not apply in conservation areas or to flats, and a building warrant will usually still be needed before work starts.
Scotland has no Party Wall Act. Work on shared walls is governed by your title deeds, the Tenements (Scotland) Act 2004 for flats, and common law, so we agree arrangements with neighbours in writing before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a single-storey extension:
- Measured survey and design drawings
- Doors, windows and roof glazing installed
- Cavity walls, insulation and roof to current building regulations
- Knock-through to the existing house with steel beams
- Foundations, drainage and any build-over agreement
- Building control inspections and completion certificate
How long does it take?
Allow 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Kirkwall
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Because Kirkwall is reached by sea, we confirm availability before quoting and list shipping and travel costs separately.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about single-storey extensions in Kirkwall
Who approves a single-storey extension in Kirkwall?
Planning matters in Kirkwall go to the council covering your address, and the work needs a building warrant. We prepare and submit the applications for you.
What is a build-over agreement?
If a public sewer runs within 3 metres of the extension, the water company normally has to agree to the work before it starts. We check sewer records during design and apply where needed.
How much does a single-storey extension cost in Kirkwall?
In Kirkwall, a single-storey extension typically costs £1,900–£2,800 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £38,000–£56,000. Your fixed price depends on the survey and drawings.
Is VAT charged on an extension?
Yes. Building work on an existing home is standard-rated, so VAT at 20% applies. Our guide prices include it.
Do I need planning permission for a single-storey extension in Kirkwall?
In Scotland a single-storey extension is often permitted development (Class 1A): where any part is within 1 metre of a boundary, it can project up to 3 metres from the rear wall of a terraced house or 4 metres on other houses, with eaves no higher than 3 metres, an overall height of 4 metres and no more than half the front or rear garden covered. The rights do not apply in conservation areas or to flats, and a building warrant will usually still be needed before work starts.
Can I stay in the house during the build?
Usually yes. We build the shell before opening up the back wall, so the house stays weathertight for most of the job. There will be a few weeks when the kitchen or back room is out of use.