Two-storey rear extensions in Johnstone

Before you start in Johnstone, here's what applies.

Postcode districts: PA5, PA9 and PA10
County / area: Renfrewshire and Inverclyde, Scotland
Price region: Scotland
Guide price: £52,500–£71,000 (£1,880–£2,540 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 rear extension

A two-storey rear extension suits you if you need more room on both floors and have a reasonably deep garden. You get one team for the whole job: a measured survey, the design, a check on whether permitted development applies, planning drawings where they are needed, structural design, a building warrant and the build itself, carried out by vetted teams working under S&K. Every project starts with a free site visit.

We cover postcode districts PA5, PA9 and PA10 in and around Johnstone, along with neighbouring Elderslie, Linwood and Houston.

What it costs in Johnstone

A guide price for Johnstone: around £52,500–£71,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). That works out at £1,880–£2,540 per m² of new floor space, including VAT at 20%. 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 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,730–£2,330 per m²	£48,500–£65,500
Standard	£1,880–£2,540 per m²	£52,500–£71,000
Premium	£2,260–£3,050 per m²	£63,000–£85,500

Planning and building standards in Johnstone

In Scotland, a two-storey rear extension is only permitted development under Class 1B if no part of it is within 10 m of any boundary, it is no higher than the house and the house is not in a conservation area. Most gardens cannot meet the 10 m test, so expect a householder application (£371, decided within two months) and a building warrant 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

Opening up the ground floor

Knocking through the old rear wall means steel beams to carry the first floor and roof above. The structural engineer sets the beam sizes, padstones and any posts, and we plan them early so the open-plan layout you want is the one that gets built.

Depth and neighbours' light

Councils check that a two-storey rear extension does not take too much light or outlook from neighbouring windows, and many use a 45-degree line drawn from the nearest habitable window. We test this at sketch stage, so the depth you are shown is one that can realistically be approved.

How we'd run your project

Visit and first ideas
One of our team visits your house in Johnstone, checks the walls, roof and drains, and sketches out options with you.
Get it approved
Once you're happy with the design we submit it to the council for Johnstone and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and a building warrant, all before anyone starts on site.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about two-storey rear extensions in Johnstone

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.

How much does a two-storey rear extension cost in Johnstone?

Our guide for Scotland, which covers Johnstone, is £1,880–£2,540 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £52,500–£71,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

How long does a two-storey rear 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.

Do I need planning permission for a two-storey rear 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.

Will a two-storey rear extension block my neighbour's light?

It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.

Nearby

We also cover places near Johnstone, including:

Other extensions in Johnstone

All two-storey extension services in Johnstone · Two-storey rear extensions across Renfrewshire and Inverclyde

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Johnstone.