Two-storey side extensions in Johnstone
Adding a two-storey side extension in Johnstone gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in Scotland.
The basics for Johnstone at a glance.
- Postcode districts
- PA5, PA9 and PA10
- County / area
- Renfrewshire and Inverclyde, Scotland
- Price region
- Scotland
- Guide price
- £81,000–£108,500 (£1,930–£2,580 per m²)
- Approval route
- Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
- Nearest towns
- Elderslie (1.2 miles), Linwood (1.6 miles), Houston (3.1 miles)
- Distance to Paisley
- about 3.2 miles
- First visit
- Free, no obligation
About a two-storey side extension
A two-storey side extension suits a detached or semi-detached house with a side garden, driveway or garage wide enough to build on. You get a design that sits comfortably on the street, a planning application or permitted development check depending on your nation, structural design, a building warrant and the build itself. We manage the whole process, and the work is carried out by vetted teams working under S&K.
Johnstone sits about 3.2 miles from Paisley. Closer to home, Elderslie is 1.2 miles away and Linwood 1.6 miles.
What it costs in Johnstone
Our guide for Scotland is £1,930–£2,580 per m² including VAT. On a project with a 3 m × 7 m footprint on two floors (42 m² of new floor space), that puts a two-storey side extension in Johnstone at roughly £81,000–£108,500. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £1,770–£2,380 per m² | £74,500–£100,000 |
| Standard | £1,930–£2,580 per m² | £81,000–£108,500 |
| Premium | £2,310–£3,100 per m² | £97,000–£130,500 |
Planning and building standards in Johnstone
In Scotland, a two-storey side extension is only permitted development under Class 1B if no part is within 10 m of any boundary and it is not on an elevation fronting a road. Side extensions rarely meet this, so plan for a householder application (£371, decided within two months) and a building warrant from the council before work starts.
Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.
Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.
Design points for Johnstone homes
Set-down and set-back
Councils usually want a two-storey side extension to look subordinate to the house. Setting the front wall back from the main front and dropping the ridge slightly below the main roof helps it read as an addition, and is often expected in local design guidance.
Matching the ridge and roof
A hipped house usually needs a hipped extension roof, and a gabled house a gable. Matching the pitch, tiles, ridge detail and brick bond is what makes a side extension look original rather than added, and councils look closely at it on a front-facing addition.
How we'd run your project
Understand the brief
At your home in Johnstone we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Scotland before drawing in detail.
Technical design
We prepare the building warrant drawings, structural calculations and specification so the build price can be fixed.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about two-storey side extensions in Johnstone
Who handles building standards for a project in Johnstone?
We handle it as part of the project. What's needed in Scotland: a building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Which postcodes do you cover around Johnstone?
We cover Johnstone (PA5, PA9 and PA10) and nearby places including Elderslie, Linwood and Houston, plus the rest of Renfrewshire and Inverclyde. The first site visit is free.
Do I need planning permission for a two-storey side extension in Johnstone?
Johnstone is in Scotland. Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
How long does a two-storey side extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils have two months to decide a local planning application), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Can I build a two-storey side extension over my driveway?
Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.
Nearby
Other towns near Johnstone:
Other extensions in Johnstone
- Rear
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Johnstone · Two-storey side extensions across Renfrewshire and Inverclyde
Book a free site visit in Johnstone and we'll tell you what's possible, what approvals you need and what the design stage would cost.