Helensburgh, Glasgow and the Clyde
Semi-detached rear extension in Helensburgh
Semi-detached rear extension in Helensburgh: single or two-storey extensions for semi-detached houses, with side access and one party wall. We measure the house, show you what the rules allow, price it in writing and build it.
Helensburgh and its postcode districts G84 are part of our Glasgow and the Clyde coverage. Semi-detached houses are common across Glasgow and the Clyde, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Helensburgh?
For Helensburgh we work from the Scotland rate: £1,800–£2,940 per square metre of new floor, including VAT, standard specification. Prices in Scotland sit a little below our West Midlands baseline; building warrant fees and drawings are budgeted separately.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,500–£35,500 |
| 4 m wide × 5 m deep (20 m²) | £36,000–£59,000 |
| 4 m wide × 6 m deep (24 m²) | £43,500–£70,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a semi-detached rear extension in Helensburgh?
Whether your semi-detached rear extension in Helensburgh needs a planning application depends on its size, your house and any local restrictions.
Scottish householder permitted development (Class 1A) covers many single-storey rear extensions, with a 3 metre eaves limit, a 4 metre height limit and, within 1 metre of a boundary, a depth limit of 3 metres for terraced houses or 4 metres for others. Conservation areas are excluded, and you need a building warrant whatever the planning position.
Scottish Class 1B rights for extensions of more than one storey need a 10 metre gap to every boundary, which few gardens have. Expect a planning application as well as a building warrant for a double-storey rear extension.
Scotland has no larger-extension prior approval route; extensions beyond permitted development need a planning application.
Classes 1A and 1B do not apply in conservation areas, and listed buildings need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Helensburgh like to extend?
Post-war semis and terraces are common around Helensburgh, and many have room for a single-storey rear extension within Class 1A limits.
How a semi-detached rear extension in Helensburgh comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for the building warrant.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the accepted completion certificate and any guarantees from suppliers.
Semi-detached rear extensions near Helensburgh
Neighbouring places we cover include Greenock (4.2 miles) and Gourock (4.7 miles).
- Semi-detached rear extension in Greenock
- Semi-detached rear extension in Gourock
- Semi-detached rear extension in Port Glasgow
- Semi-detached rear extension in Vale of Leven
- Semi-detached rear extension in Dumbarton
Other work in Helensburgh:
FAQ
Semi-detached rear extension questions in Helensburgh
Can you match the brick or stone on my Helensburgh house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Do you handle building control in Helensburgh?
Yes. We apply for the building warrant before work starts and submit the completion certificate at the end.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
What postcode areas do you cover around Helensburgh?
Including G84, and the surrounding Glasgow and the Clyde area.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.