What is a double-storey extension?
A double-storey extension (also called a two-storey extension) adds rooms on both the ground and first floor in one build. It typically gives a larger kitchen or living space downstairs and an extra bedroom or bathroom above.
How much does a double-storey extension cost in Lanarkshire?
In Lanarkshire, a double-storey extension typically costs £1,600–£2,400 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £57,500–£86,500. Prices in Scotland sit near the national average for this kind of work, and the range for Lanarkshire reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £40,000–£60,000 |
| Typical project (36 m²) | £57,500–£86,500 |
| Larger project (50 m²) | £80,000–£120,000 |
| Rate per m² | £1,600–£2,400 |
The main things that change the cost:
- Steel beams where walls are opened up
- Roof design and how it joins the existing roof
- Total floor area across both floors
- Bathrooms or en-suites on the first floor
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a double-storey extension in Lanarkshire?
Here is how the rules work for a double-storey extension in Scotland. In Scotland an extension of more than one storey is only permitted development if it is at least 10 metres from every boundary and no higher than the existing ridge, so most need planning permission. A building warrant is 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most double-storey extensions:
- Brick or block walls, floors and a roof tied into the house
- Structural engineer’s calculations
- Building control sign-off
- Electrics, heating, plumbing and plastering
- Opening up at both levels with steel beams
- Design drawings and planning application
How long does it take?
Build time is typically 14 to 20 weeks on site, after planning and building control approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Lanarkshire
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Towns we cover in Lanarkshire include East Kilbride, Hamilton, Cumbernauld, Coatbridge, Airdrie and Motherwell.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed 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 double-storey extensions in Lanarkshire
Do I need planning permission for a double-storey extension in Lanarkshire?
In Scotland an extension of more than one storey is only permitted development if it is at least 10 metres from every boundary and no higher than the existing ridge, so most need planning permission. A building warrant is needed before work starts.
How much does a double-storey extension cost in Lanarkshire?
In Lanarkshire, a double-storey extension typically costs £1,600–£2,400 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £57,500–£86,500. Your fixed price depends on the survey and drawings.
How close can it be to my neighbour?
Councils look at loss of light and outlook for neighbours. Many apply a 45-degree guideline from the nearest neighbouring window. We design to the council’s published guidance to give the application the best chance.
How long does a double-storey extension take in Lanarkshire?
Typically 14 to 20 weeks on site, after planning and building control approval. Design and approvals beforehand usually take 3 to 4 months.
What drawings do I need?
Planning drawings for the application, then more detailed building regulations drawings and structural calculations for building control. We prepare both.
Is a double-storey extension cheaper per square metre?
Usually yes. You pay for one set of foundations and one roof but get two floors of space, so the cost per square metre is often lower than a single-storey extension.