Mountain Ash, South Wales Valleys
Terraced house rear extension in Mountain Ash
Terraced house rear extension in Mountain Ash: rear and side return extensions for terraces, with access through the house and two neighbours. We measure the house, show you what the rules allow, price it in writing and build it.
We cover Mountain Ash (CF43 and CF45) as part of our South Wales Valleys work. On a Mountain Ash 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 Mountain Ash?
Guide prices for a terraced house rear extension in Mountain Ash 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 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a terraced house rear extension in Mountain Ash?
Whether your terraced house rear extension in Mountain Ash needs a planning application depends on its size, your house and any local restrictions.
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. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Mountain Ash like to extend?
Mountain Ash 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 Mountain Ash 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.
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.
Terraced house rear extensions near Mountain Ash
From Mountain Ash, the nearest places we also cover are Treharris (3.4 miles) and Rhondda (3.4 miles).
- Terraced house rear extension in Treharris
- Terraced house rear extension in Rhondda
- Terraced house rear extension in Aberdare
- Terraced house rear extension in Merthyr Tydfil
- Terraced house rear extension in Nelson
Other work in Mountain Ash:
FAQ
Terraced house rear extension questions in Mountain Ash
What postcode areas do you cover around Mountain Ash?
Including CF43 and CF45, and the surrounding South Wales Valleys area.
Can you match the brick or stone on my Mountain Ash house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Can you build without side access?
Yes. Materials come through the house in protected runs or over the roof by crane on tight sites.
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.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
How much does a terraced house rear extension cost in Mountain Ash?
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.