Perth, Perth and Kinross
Semi-detached rear extension in Perth
We plan and build rear extensions for semi-detached houses for homeowners in Perth. Single or two-storey extensions for semi-detached houses, with side access and one party wall. Start with a free site visit, then a written price once the design is agreed.
We cover Perth (PH1 and PH2) as part of our Perth and Kinross work. In Perth we measure the attached neighbour's extension at the survey, because it often sets the sensible depth for yours.
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 Perth?
For Perth 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 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a semi-detached rear extension in Perth?
Here is how the rules in Scotland apply to a semi-detached rear extension in Perth.
In Scotland a single-storey rear extension can be permitted development under Class 1A: eaves no higher than 3 metres and an overall height of 4 metres, and where any part is within 1 metre of a boundary it can project no more than 3 metres on a terraced house or 4 metres on other houses. The rights do not apply in conservation areas, and a building warrant is still needed before work starts.
In Scotland an extension of more than one storey is only permitted development (Class 1B) if no part is within 10 metres of any boundary and it is no higher than the existing house, so almost every two-storey rear extension needs planning permission and a building warrant.
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. At the first visit we measure what is there now and tell you which route fits: permitted development or a planning application, plus the building warrant.
What are homes in Perth like to extend?
Perth has sandstone tenements, terraced houses and villas closer in, with post-war semis and newer estates further out. Tenement and other flats need planning permission for an extension, and every project needs a building warrant before work starts.
How a semi-detached rear extension in Perth comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Approvals
Permitted development check or planning application, then building warrant drawings and structural calculations, plus a written agreement with neighbours for any shared-wall work.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Semi-detached rear extensions near Perth
From Perth, the nearest places we also cover are Scone (2.0 miles) and Auchterarder (12.6 miles).
- Semi-detached rear extension in Scone
- Semi-detached rear extension in Auchterarder
- Semi-detached rear extension in Blairgowrie and Rattray
- Semi-detached rear extension in Crieff
- Semi-detached rear extension in Glenrothes
Other work in Perth:
FAQ
Semi-detached rear extension questions in Perth
How much does a semi-detached rear extension cost in Perth?
As a guide, £1,800–£2,940 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,500–£35,500 at that rate. Your written price follows the survey.
How long does a rear extension take to build in Perth?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Single or two-storey on a semi?
Two-storey if you need bedrooms, single-storey if you need a bigger kitchen. Planning risk is lower for single-storey.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Do I need planning permission for a rear extension in Perth?
Many single-storey rear extensions are permitted development under Class 1A, but not in conservation areas; you always need a building warrant before work starts.
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.