Side extensions across Forth Valley
A side extension in Forth Valley starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide priceFrom £21,500 inc VAT
- PlanningScottish householder rules; building warrant needed
- Towns covered4
- Site visitFree, no obligation

Towns in Forth Valley
Who a side extension suits
- Detached and semi-detached houses with side land
- Houses where the rear garden is small
- Homes needing a utility, study or ground-floor bedroom
Covering Forth Valley
Towns we cover in Forth Valley include Stirling, Falkirk, Alloa, Grangemouth. Across Scotland, extensions follow Scottish planning and building standards, including the building warrant process, which we build into the programme from the start.
Guide prices for Forth Valley
Labour and material costs vary across the UK, so for Forth Valley we use our Scotland factor (×0.98). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Forth Valley: £1,720 to £3,330 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £21,500 – £26,000 | £24,000 – £31,500 | £30,500 – £40,000 |
| 3 m × 6 m 18 m² | £30,500 – £37,500 | £36,000 – £47,000 | £45,500 – £60,000 |
| 3 m × 8 m 24 m² | £41,000 – £49,500 | £48,000 – £62,500 | £61,000 – £80,000 |
For a figure based on your own dimensions, use our guide-price tool.
Do I need planning permission in Forth Valley?
In Scotland, householder permitted development rules (Class 1A for single-storey ground-floor extensions and Class 1B for extensions of more than one storey) allow some smaller extensions without a planning application, within limits on depth, height and distance from the boundary. Conservation areas and listed buildings are more restricted.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
In Scotland a building warrant from the council is needed before work starts on almost any extension, and a completion certificate is issued when the work is accepted. Building standards are set in the Scottish technical handbooks.
Building close to a public sewer needs the agreement of Scottish Water, which we check during design.
Applications are decided by your council as planning authority.
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Forth Valley home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Forth Valley
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Forth Valley, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need building regulations approval in Forth Valley?
Yes. Almost every extension needs it, whatever the planning route. In Scotland that means a building warrant before work starts.
How long does a side extension take to build in Forth Valley?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
How much does a side extension cost?
Our guide range is about £1,720 to £3,330 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £36,000 to £47,000 in Forth Valley.
Book a free site visit in Forth Valley
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.