Helensburgh · Argyll and Bute

Two-storey side extensions in Helensburgh

Thinking about a two-storey side extension in Helensburgh? We design it, take it through the approvals it needs and build it, with one team responsible from the first visit to the final certificate.

What we'd confirm first for a project in Helensburgh.

Postcode districts
G84
County / area
Argyll and Bute, 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
Greenock (4.2 miles), Gourock (4.7 miles), Port Glasgow (5.1 miles)
First visit
Free, no obligation

About a two-storey side extension

A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.

Around Helensburgh we also work in Greenock, Gourock and Port Glasgow, and across the rest of Argyll and Bute. Postcode district in and near Helensburgh: G84.

What it costs in Helensburgh

Expect a two-storey side extension in Helensburgh to land somewhere around £81,000–£108,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Our Scotland guide rate is £1,930–£2,580 per m², including VAT. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

SpecPer m²A 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 Helensburgh

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 Helensburgh homes

Avoiding a terracing effect

Where semi-detached houses sit close together, side extensions on neighbouring houses can join up and turn a row of pairs into a terrace. Many councils ask for a gap to the boundary at first floor to stop this, so we check local guidance before fixing the width.

Access and services

Side extensions often cover the only route to the back garden, a gas meter, soil pipes or a drain run. We plan bin and bike access, move meters and pipes where needed and check drains early, because these items affect both cost and layout.

How we'd run your project

  1. Measure and listen

    A visit to Helensburgh to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.

  2. Choose the approval route

    Some designs fit permitted development, most need a householder application. We decide which applies in Scotland before drawing in detail.

  3. Detail and price

    Construction drawings, engineer's calculations and building warrant approval, then a written fixed price for the build.

  4. Finish and certify

    Second fix, plastering and making good, then the council's final building standards inspection and the completion paperwork.

Questions about two-storey side extensions in Helensburgh

Which postcodes do you cover around Helensburgh?

We cover Helensburgh (G84) and nearby places including Greenock, Gourock and Port Glasgow, plus the rest of Argyll and Bute. The first site visit is free.

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.

How much does a two-storey side extension cost in Helensburgh?

Our guide for Scotland, which covers Helensburgh, is £1,930–£2,580 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £81,000–£108,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Do I need planning permission for a two-storey side extension in Helensburgh?

Helensburgh 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.

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 Helensburgh:

Other extensions in Helensburgh

All two-storey extension services in Helensburgh · Two-storey side extensions across Argyll and Bute

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