What is a side extension?

A side extension builds into the space beside a semi-detached or detached house, often over a driveway or side passage. It can be single-storey, for a utility room, downstairs toilet or study, or two-storey to add a bedroom above.
How much does a side extension cost in Tayside?
In Tayside, a side extension typically costs £1,650–£2,550 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £46,000–£71,500. Prices in Scotland sit near the national average for this kind of work, and the range for Tayside reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £33,000–£51,000 |
| Typical project (28 m²) | £46,000–£71,500 |
| Larger project (39 m²) | £64,500–£99,500 |
| Rate per m² | £1,650–£2,550 |
The biggest cost drivers are:
- Steel work where the side wall is opened
- Single or two storeys
- Roof design and tile matching
- Boundary walls and access for materials
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 side extension in Tayside?
Whether you need planning permission depends on your house and its location in Scotland. In Scotland single-storey side extensions can be permitted development if they do not come forward of a side wall facing a road and stay within the height and boundary limits. Two-storey side extensions usually need planning permission, and a building warrant is needed before work starts.
In Scotland a building warrant is needed before work starts on most extensions, loft conversions and conversions. It is issued by the council’s building standards service. When the work is finished, a completion certificate is submitted and accepted by the council after inspection.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
On a typical side extension we handle:
- Survey of the boundary, drains and access
- Planning drawings and application
- Building control completion
- Walls, roof and windows to match the house
- Foundations and drainage alterations
- Structural calculations
How long does it take?
Allow 10 to 16 weeks on site depending on size and storeys. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Tayside
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.
Towns we cover in Tayside include Dundee, Perth, Arbroath, Forfar and Montrose.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 side extensions in Tayside
How long does it take?
Roughly 10 to 16 weeks on site once approvals are in place, depending on whether it is one or two storeys.
Will I lose my driveway?
A side extension often takes the side drive. We look at whether parking can be kept at the front and whether a dropped kerb is needed.
How much does a side extension cost in Tayside?
In Tayside, a side extension typically costs £1,650–£2,550 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £46,000–£71,500. Your fixed price depends on the survey and drawings.
Do I need planning permission for a side extension in Tayside?
In Scotland single-storey side extensions can be permitted development if they do not come forward of a side wall facing a road and stay within the height and boundary limits. Two-storey side extensions usually need planning permission, and a building warrant is needed before work starts.
Can a side extension go over a drain?
Often yes, with a build-over agreement from the water company or by rerouting the drain. We check this during the survey.
Do you build side extensions in Tayside?
Yes. We build side extensions across Tayside, including postcodes AB30, DD1, DD10, DD11 and DD2. Every project starts with a free home visit.
