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 Larkhall?
In Larkhall, 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. Building costs in Scotland are close to the UK average, so the figures for Larkhall are close to our national guide. 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 |
What moves the price most:
- Kitchen, flooring and finishes, which we can include or leave to you
- Glazing: sliding and bifold doors cost more than French doors
- Ground conditions and foundation depth
- Roof type and the size of any lantern or roof windows
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 Larkhall?
Approvals for a single-storey extension in Larkhall follow the rules for 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a single-storey extension:
- Building control inspections and completion certificate
- Doors, windows and roof glazing installed
- Measured survey and design drawings
- 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
How long does it take?
Build time is typically 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 Larkhall
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Our Larkhall coverage includes postcode districts ML9, and we also work in nearby places such as Wishaw, Hamilton and Motherwell.
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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about single-storey extensions in Larkhall
Do you build single-storey extensions in Larkhall?
Yes. We build single-storey extensions across Larkhall, including postcodes ML9. Every project starts with a free home visit.
How long does a single-storey extension take?
Once approvals are in place, a typical rear extension takes 10 to 14 weeks on site. Design and approvals usually take another 6 to 12 weeks beforehand, depending on whether a planning application is needed.
Do I need planning permission for a single-storey extension in Larkhall?
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.
How much does a single-storey extension cost in Larkhall?
In Larkhall, 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.
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.
