South Wales Valleys
Rear extensions in Caerphilly
From the first measured visit to building control sign-off, we handle rear extensions in Caerphilly under one contract.
Caerphilly is in the South Wales Valleys, with postcode districts including CF83. The nearest places we also cover are Rhiwbina (3.2 miles) and Whitchurch (4.3 miles).
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
Rear extensions we build in Caerphilly
- Single-storey rear extensions
- Two-storey rear extensions
- Kitchen-diner rear extensions
- Side return extensions
- Wraparound extensions
- Glazed and glass-box rear extensions
- Rear extensions for terraced houses
- Rear extensions for semi-detached houses
- Rear extensions for bungalows
- Rear extension plans and planning applications
Also available across the South Wales Valleys:
- Rear extensions for detached houses
- Flat-roof rear extensions
- Pitched and lean-to roof rear extensions
- Knocking through to a rear extension
- Roof lanterns and rooflights for rear extensions
- Permitted development rear extensions
- Building Regulations for rear extensions
Rear extension prices in Caerphilly
Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Example | Guide inc VAT |
|---|---|
| Single-storey, 3 m × 4 m (12 m²) | £21,000–£34,500 |
| Single-storey, 4 m × 6 m (24 m²) | £42,500–£69,000 |
| Two-storey, 3 m × 5 m footprint (30 m²) | £50,000–£75,500 |
| Side return, about 14 m² | £30,000–£49,500 |
| Wraparound, about 25 m² | £51,000–£83,500 |
What are homes in Caerphilly like to extend?
Stone terraces along the valley floors and post-war semis higher up are typical of Caerphilly. Sloping sites are common, so floor levels and retaining walls are designed at the start.
Planning rules for Caerphilly
The Welsh Government's householder rules let many homes add a single-storey rear extension up to 4 metres deep and 4 metres high without a planning application. Deeper projects go through a householder application, because Wales has no prior approval route.
Welsh building regulations apply to every rear extension. The council or a registered approver checks the work against the Welsh Approved Documents and issues a completion certificate.
Nearby towns
FAQ
Questions people ask
How much is a rear extension in Caerphilly?
A 3 m × 4 m single-storey rear extension is about £21,000–£34,500 including VAT at our Wales guide rates; the written price follows a survey.
Do I need planning permission in Caerphilly?
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.
Is the site visit in Caerphilly free?
Yes, with no obligation.
Do I need a party wall agreement?
In Wales, usually yes if the extension is on or near a shared boundary or close to a neighbour's foundations. We serve the notices.