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 Montrose?
In Montrose, 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. Building costs in Scotland are close to the UK average, so the figures for Montrose are close to our national guide. 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 |
What moves the price most:
- Internal fit-out of the new rooms
- Steel work where the side wall is opened
- Drains, gas meters or soil pipes that need moving
- Roof design and tile matching
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 side extension in Montrose?
Here is how the rules work for a side extension 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.
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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical side extension we handle:
- Electrics, heating and plastering
- Walls, roof and windows to match the house
- Opening into the existing house
- Foundations and drainage alterations
- Planning drawings and application
- Survey of the boundary, drains and access
How long does it take?
Allow 10 to 16 weeks on site depending on size and storeys. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Montrose
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Projects in Montrose (DD10) are surveyed in person before we quote, so the price reflects your actual property.
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 side extensions in Montrose
How long does a side extension take in Montrose?
Typically 10 to 16 weeks on site depending on size and storeys. Design and approvals beforehand usually take 3 to 4 months.
Do I need planning permission for a side extension in Montrose?
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.
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.
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.
Will a two-storey side extension look odd?
Not if it is designed well. Setting it back from the front and keeping the roof lower than the main ridge usually gives a natural look and is what most councils ask for.
How much does a side extension cost in Montrose?
In Montrose, 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.
