Grangemouth double-storey extensions, designed and built
From the first sketch to final sign-off, we plan and build double-storey extensions in Grangemouth and the surrounding Forth Valley area.
- Guide price in GrangemouthFrom £37,000 inc VAT
- PlanningUsually planning permission; building warrant needed
- Build time16–24 weeks on site
- Postcode districtsFK2, FK3

Double-storey extension prices in Grangemouth
These guide figures apply our Scotland adjustment (×0.98) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Grangemouth: £1,520 to £2,940 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £37,000 – £44,500 | £42,000 – £55,500 | £54,000 – £71,000 |
| 4 m × 4 m, two floors 32 m² | £48,500 – £58,500 | £56,000 – £74,000 | £72,000 – £94,500 |
| 4 m × 6 m, two floors 48 m² | £72,500 – £87,500 | £84,500 – £111,000 | £108,000 – £141,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What we take care of
- Measured survey, design and planning drawings
- Building regulations drawings and structural design
- Ground and first floor structure, roof tied into the existing roof
- Householder planning application where needed
- Breaking through at both levels, stairs and landing changes where needed
- Foundations sized for two floors
The roof is what makes a two-storey extension look right or wrong. We match the pitch and materials of the main house wherever possible and plan the upstairs layout around the existing landing so the new rooms feel original rather than bolted on.
Do I need planning permission in Grangemouth?
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. Separately, almost every extension needs a building warrant from the council before work starts.
In a conservation area or national scenic area the householder permitted development rights are more limited, listed homes need listed building consent, and if rights have been removed by a condition or direction, any extension needs an application.
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.
Extensions in and around Grangemouth
Postcode districts we cover around Grangemouth include FK2, FK3. The same team covers Falkirk (3 miles), Alloa (8 miles), Stirling (11 miles), all within easy reach.
Bathgate, in Edinburgh and the Lothians, is roughly 8 miles from Grangemouth and also on our list. Scotland's housing includes sandstone villas, terraces and tenements in the cities and plenty of post-war and modern houses and bungalows elsewhere. A building warrant is needed before work starts.
Our process, step by step
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Grangemouth
Who do I contract with for a double-storey extension in Grangemouth?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Grangemouth, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Grangemouth be involved?
If a planning application is needed, the council notifies neighbours. Where work is close to a shared boundary, we agree access and protection with them in writing.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,520 to £2,940 per m² of new floor area including VAT, compared with £1,720 to £3,330 per m² for single-storey work, because the foundations and roof are shared across two floors.
Book a free site visit in Grangemouth
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.