Local costs · Wales · September 2026
How much does an extension cost in Vale of Glamorgan?
A mid-range 25 m² single-storey extension in Vale of Glamorgan costs about £56,500 to £70,000 including VAT, or £2,300 to £2,800 per m² at Welsh prices. Vale of Glamorgan charges £540 for building control on a 10 to 40 m² extension (full plans, including VAT): the 2nd cheapest of the 91 councils we checked, 36% below the typical council (£840), though its published schedule is older or undated. With design, a structural engineer, building control and a 15% contingency, budget £71,000 to £92,000.
Work out your project in Vale of Glamorgan
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Typical prices in Vale of Glamorgan
| Project | Building work | Budget to plan for |
|---|---|---|
| Single-storey extension, 25 m² | £56,500 to £70,000 | £71,000 to £92,000 |
| Double-storey extension, 40 m² | £82,000 to £104,000 | £101,000 to £133,000 |
| Dormer loft conversion, 30 m² | £51,000 to £62,500 | £63,500 to £81,500 |
| Kitchen, medium | £8,600 to £15,200 | £9,800 to £17,500 |
| Bathroom refit | £5,600 to £8,500 | £6,500 to £9,700 |
Building prices in Wales run about 10% below the UK average outside London. Kitchens and bathrooms vary less from place to place than extensions and lofts.
Building control fees in Vale of Glamorgan
| Work | Charge |
|---|---|
| Extension up to 10 m² (full plans) | £405 |
| Extension 10 to 40 m² (full plans) | £540 |
| Larger extension, 40-100 m² (full plans) | £698 |
| Extension 10 to 40 m² (building notice) | Not published |
| Loft conversion up to 40 m² | £630 |
| Garage conversion | £360 |
Vale of Glamorgan charges £540 for building control on a 10 to 40 m² extension (full plans, including VAT): the 2nd cheapest of the 91 councils we checked, 36% below the typical council (£840), though its published schedule is older or undated. Source: Vale of Glamorgan's building control charges, 1 April 2023. Inc VAT total column.
Check before relying on it: the schedule is older than 2025 or undated, so check it is still current.
Private approved inspectors set their own prices and are often competitive, so it is worth asking one or two for a quote as well. See how Vale of Glamorgan compares with every council we checked.
Notes on Vale of Glamorgan's schedule
Own schedule. Single total fee. Loft figure is with dormer (without 562.50).
Planning
In Wales, householder planning fees are set by the Welsh Government. Check the current fee on Planning Portal before you apply.
Other councils in Wales
Building control for a 10 to 40 m² extension:
- Newport: £485
- Bridgend: £587
- Conwy: £648
- Gwynedd: £684
- Pembrokeshire: £780
- Ceredigion: £886
- Monmouthshire: £1,056
Questions people ask
How much does an extension cost in Vale of Glamorgan?
A mid-range 25 m² single-storey extension in Vale of Glamorgan costs about £56,500 to £70,000 including VAT for the building work, or £2,300 to £2,800 per m², based on Wales prices reviewed in September 2026. With fees and a 15% contingency, budget £71,000 to £92,000.
How much is building control in Vale of Glamorgan?
Vale of Glamorgan charges £540 (including VAT) for a 10 to 40 m² extension (full plans), according to its published schedule (1 April 2023).
How much does a loft conversion cost in Vale of Glamorgan?
A mid-range 30 m² dormer loft conversion in Vale of Glamorgan costs about £51,000 to £62,500 including VAT for the building work, and about £63,500 to £81,500 with fees and a 15% contingency.
Before you get quotes
- How to compare builders' quotes line by line
- Plan your whole budget, including the costs people forget
- Trades: price an extension element by element with editable unit rates