Covering West Glamorgan
Our double-storey extensions service in West Glamorgan covers Swansea, Neath, Ystalyfera and Pontarddulais.
Homes in West Glamorgan
Welsh homes include long terraces built into hillsides, stone cottages and modern estates, and sloping sites often shape how and where an extension can go.
What is a double-storey extension?
A double-storey extension adds new rooms on both the ground and first floor in one build, typically a larger kitchen or living space downstairs and an extra bedroom or bathroom above. Because the roof and foundations are shared, the cost per square metre is usually lower than a single-storey extension.
- Measured survey, design and planning drawings
- Structural engineer’s design and calculations
- Foundations, steelwork, brick and block walls, roof
What is the guide price for a double-storey extension in West Glamorgan?
Use these ranges to budget for double-storey extensions; the survey turns them into a fixed price for the agreed specification.
| Double-storey extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £2,400 to £2,900 per m² |
| Good specification | £2,900 to £3,400 per m² |
| High specification | £3,400 to £3,850 per m² |
Do you need permission for a double-storey extension in West Glamorgan?
In Wales the planning rules, including what counts as permitted development, are set by the Welsh Government, and Welsh building regulations differ in places from England’s. We check both against your house before drawings are finalised, and handle party wall notices where needed.
Most two-storey extensions in Wales need householder planning permission from the council. We prepare and submit the application and deal with any questions from the planning officer.
What can affect a double-storey extension?
- Side extensions close to a boundary are often set back or stepped down so they do not create a terraced effect.
- The first-floor link can mean moving a bathroom or reshaping the landing.
How does the project run?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
What people ask before starting
How much does a two-storey extension cost?
Typically about £2,400 to £3,850 per square metre of new floor area including VAT. A 40 m² extension across two floors is often around £100,000 to £150,000 depending on specification.
Will we need to move out?
Most people stay. The noisiest stage is when we break through into the existing first floor, which we plan for a short window.
Who deals with the council for a project in West Glamorgan?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Double-storey extensions near West Glamorgan
- Double-storey extensions in Swansea
- Double-storey extensions in Neath
- Double-storey extensions in Ystalyfera
- Double-storey extensions in Pontarddulais
Learn more about double-storey extensions, or see every project we cover in West Glamorgan.

