What is a side extension?
A side extension builds into the space beside a semi-detached or detached house, often over a driveway or side passage. It can be single-storey, for a utility room, downstairs toilet or study, or two-storey to add a bedroom above.
How much does a side extension cost in Bridgend?
In Bridgend, a side extension typically costs £1,550–£2,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £43,500–£68,500. Building costs in Wales run about 8% below the UK average, and the figures for Bridgend are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £31,000–£49,000 |
| Typical project (28 m²) | £43,500–£68,500 |
| Larger project (39 m²) | £60,500–£95,500 |
| Rate per m² | £1,550–£2,450 |
The main things that change the cost:
- Internal fit-out of the new rooms
- Drains, gas meters or soil pipes that need moving
- Steel work where the side wall is opened
- Boundary walls and access for materials
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a side extension in Bridgend?
Here is how the rules work for a side extension in Wales. In Wales a single-storey side extension can be permitted development if it is no more than 4 metres high and the widest part of the house ends up no more than 50% wider than the original. Two-storey side extensions must be at least 10.5 metres from the side boundary and set back 1 metre from the front, so most need planning permission. In conservation areas single-storey side extensions are limited to 3 metres.
The Party Wall etc. Act 1996 applies in Wales, so notices must be served before work on a shared wall, on the boundary, or excavation close to a neighbour’s foundations.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a side extension:
- Electrics, heating and plastering
- Survey of the boundary, drains and access
- Building control completion
- Walls, roof and windows to match the house
- Structural calculations
- Foundations and drainage alterations
How long does it take?
The build itself usually takes 10 to 16 weeks on site depending on size and storeys. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Bridgend
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
We work across Bridgend and neighbouring areas such as Porthcawl, Maesteg and Tonypandy. Postcodes we cover in Bridgend include CF31.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side extensions in Bridgend
How close to the boundary can I build?
You can build up to the boundary, but the eaves height near it is limited under permitted development, and planning officers often want a gap at first floor. If you build on or near a shared boundary, party wall rules may apply.
Do I need planning permission for a side extension in Bridgend?
In Wales a single-storey side extension can be permitted development if it is no more than 4 metres high and the widest part of the house ends up no more than 50% wider than the original. Two-storey side extensions must be at least 10.5 metres from the side boundary and set back 1 metre from the front, so most need planning permission. In conservation areas single-storey side extensions are limited to 3 metres.
How long does a side extension take in Bridgend?
Typically 10 to 16 weeks on site depending on size and storeys. Design and approvals beforehand usually take 3 to 4 months.
How much does a side extension cost in Bridgend?
In Bridgend, a side extension typically costs £1,550–£2,450 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £43,500–£68,500. Your fixed price depends on the survey and drawings.
Will I lose my driveway?
A side extension often takes the side drive. We look at whether parking can be kept at the front and whether a dropped kerb is needed.
Can a side extension go over a drain?
Often yes, with a build-over agreement from the water company or by rerouting the drain. We check this during the survey.