Treharris, South Wales Valleys
Terraced house rear extension in Treharris
Rear and side return extensions for terraces, with access through the house and two neighbours. We design, get the approvals for and build rear extensions for terraced houses in Treharris and the surrounding area, with one contract from the first survey to building control sign-off.
Treharris sits in the South Wales Valleys, with postcode districts including CF46. On a Treharris terrace both neighbours usually need party wall notices or agreement, so we talk to them early.
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 terraced house rear extension cost in Treharris?
Guide prices for a terraced house rear extension in Treharris start from our Wales rate of £1,910–£3,070 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 × 4.5 m deep (13.5 m²) | £25,500–£41,500 |
| 3 m wide × 6 m deep (18 m²) | £34,500–£55,000 |
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 terraced house rear extension in Treharris?
Here is how the rules in Wales apply to a terraced house rear extension in Treharris.
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.
The Party Wall etc. Act 1996 also applies in Wales: two months' notice for work to a shared wall and one month for foundations dug close to a neighbour's building.
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 Treharris like to extend?
Treharris is largely terraced streets on sloping ground, where back gardens step up or down from the house. Excavation, retaining walls and drainage are priced at the survey.
How a terraced house rear extension in Treharris comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
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.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Terraced house rear extensions near Treharris
We also build rear extensions for terraced houses in nearby Nelson (1.2 miles) and Gelligaer (2.2 miles).
- Terraced house rear extension in Nelson
- Terraced house rear extension in Gelligaer
- Terraced house rear extension in Mountain Ash
- Terraced house rear extension in Bargoed
- Terraced house rear extension in Blackwood
Other work in Treharris:
FAQ
Terraced house rear extension questions in Treharris
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.
Can you match the brick or stone on my Treharris house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How do you keep the house clean?
Dust screens, floor protection and a single protected route through the house.
How much does a terraced house rear extension cost in Treharris?
As a guide, £1,910–£3,070 per square metre including VAT for a standard specification. For example, 3 m wide × 4.5 m deep (13.5 m²): about £25,500–£41,500 at that rate. Your written price follows the survey.
How long does a rear extension take to build in Treharris?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
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.