Johnstone side extensions, designed and built
Thinking about a side extension for your Johnstone home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in JohnstoneFrom £21,500 inc VAT
- PlanningScottish householder rules; building warrant needed
- Build time10–18 weeks on site
- Postcode districtsPA5, PA10
Planning rules that apply in Johnstone
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.
The planning position for a specific Johnstone address depends on its history and any designations, which is why we check it at the first visit.
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.
Guide prices for Johnstone
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 Johnstone: £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 |
Try the guide-price tool to see a range for your own size and finish.
What we take care of
- Foundations near boundaries and any drains
- Windows, doors and finishes to match
- Structure, roof tied into the house
- New openings through the side wall
- Planning route checked or application made
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
Working in Johnstone
Site visits are available across Johnstone (PA5, PA10). We also work in nearby Paisley (3 miles), Barrhead (5 miles), Erskine (6 miles), Renfrew (6 miles).
Clydebank, in Dunbartonshire, is roughly 7 miles from Johnstone and also on our list. Across Scotland, extensions follow Scottish planning and building standards, including the building warrant process, which we build into the programme from the start.
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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 Johnstone
Will my neighbours in Johnstone 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.
Do you cover all of Johnstone?
Yes. We cover Johnstone and the surrounding parts of Renfrewshire and Inverclyde. Site visits are free and there is no obligation.
Do I need building regulations approval in Johnstone?
Yes. Almost every extension needs it, whatever the planning route. In Scotland that means a building warrant before work starts.
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 Johnstone.
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.
Book a free site visit in Johnstone
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.