Coity, South Wales Valleys
Semi-detached rear extension in Coity
For homes in Coity, a semi-detached rear extension is often the simplest way to gain space without moving. Single or two-storey extensions for semi-detached houses, with side access and one party wall. We take it from survey to completion certificate.
Coity is covered from our South Wales Valleys round, including CF31, CF32 and CF35. In Coity 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 Coity?
Guide prices for a semi-detached rear extension in Coity start from our Wales rate of £1,770–£2,880 per square metre, including VAT. Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a semi-detached rear extension in Coity?
Here is how the rules in Wales apply to a semi-detached rear extension in Coity.
In Wales a single-storey rear extension can often be permitted development if it projects no more than 4 metres beyond the rear wall and is no more than 4 metres high. Wales has no prior approval route for deeper extensions, so anything bigger needs a householder planning application.
Welsh rules allow a two-storey rear extension without an application only where the ground floor is no deeper than 4 metres, the upper floor no deeper than 3 metres and at least 10.5 metres remains to the rear boundary. Most homeowners still apply for householder planning permission.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, 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 Coity like to extend?
Stone terraces along the valley floors and post-war semis higher up are typical of Coity. Sloping sites are common, so floor levels and retaining walls are designed at the start.
How a semi-detached rear extension in Coity 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Coity
We also build rear extensions for semi-detached houses in nearby Bridgend (1.5 miles) and Aberkenfig (2.1 miles).
- Semi-detached rear extension in Bridgend
- Semi-detached rear extension in Aberkenfig
- Semi-detached rear extension in Pyle
- Semi-detached rear extension in Porthcawl
- Semi-detached rear extension in Maesteg
Other work in Coity:
FAQ
Semi-detached rear extension questions in Coity
What postcode areas do you cover around Coity?
Including CF31, CF32 and CF35, and the surrounding South Wales Valleys area.
Is the site visit in Coity free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How long does a semi extension take?
10 to 16 weeks on site for a single-storey extension.
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.
How much does a semi-detached rear extension cost in Coity?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.
Do I need planning permission for a rear extension in Coity?
Often not for a single-storey rear extension of up to 4 metres under Welsh permitted development. Wales has no prior approval route for deeper extensions.