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 Stonehaven?
In Stonehaven, 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. Building costs in Scotland are close to the UK average, so the figures for Stonehaven are close to our national guide. 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 |
What moves the price most:
- Brick matching and external finishes
- Bathrooms or en-suites on the first floor
- Total floor area across both floors
- Steel beams where walls are opened up
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a double-storey extension in Stonehaven?
Whether you need planning permission depends on your house and its location 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most double-storey extensions:
- Structural engineer’s calculations
- Brick or block walls, floors and a roof tied into the house
- Design drawings and planning application
- Building control sign-off
- Windows, doors and staircase alterations
- Opening up at both levels with steel beams
How long does it take?
Allow 14 to 20 weeks on site, after planning and building control approval. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Stonehaven
Scotland’s housing ranges from sandstone tenements and villas to post-war and modern estates, and the building warrant system shapes how projects are planned.
Our Stonehaven coverage includes postcode districts AB39, and we also work in nearby places such as Aberdeen, Westhill and Montrose.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in Stonehaven
How long does a double-storey extension take in Stonehaven?
Typically 14 to 20 weeks on site, after planning and building control approval. Design and approvals beforehand usually take 3 to 4 months.
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.
Will the first floor need a new staircase?
Not normally. The new rooms are reached from the existing landing, though a doorway or short corridor may need to be formed.
Do I need planning permission for a double-storey extension in Stonehaven?
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.
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.
How much does a double-storey extension cost in Stonehaven?
In Stonehaven, 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.
