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 £57,000 to £70,000 including VAT, or £2,300 to £2,800 per m² at Welsh prices. Vale of Glamorgan’s own published charge for building control on a 10 to 40 m² extension is £540 (full plans, including VAT): the 2nd cheapest of the 91 councils we checked, 36% below the typical council (£840). The council’s published fee list is older or has no date, so check the current fee with the council before you budget. With a measured survey, building regulations drawings, a structural engineer, Vale of Glamorgan’s own building control charge and a 15% contingency, plan for £69,500 to £88,500.
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 | £57,000 to £70,000 | £69,500 to £88,500 |
| Double-storey extension, 40 m² | £82,000 to £104,000 | £99,000 to £129,000 |
| Dormer loft conversion, 30 m² | £42,500 to £52,000 | £52,000 to £67,500 |
| 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 to 100 m² (full plans) | £697.50 |
| Extension 10 to 40 m² (building notice) | Not published |
| Loft conversion up to 40 m² | £630 |
| Garage conversion | £360 |
Vale of Glamorgan’s own published charge for building control on a 10 to 40 m² extension is £540 (full plans, including VAT): the 2nd cheapest of the 91 councils we checked, 36% below the typical council (£840). The council’s published fee list is older or has no date, so check the current fee with the council before you budget. Source: Vale of Glamorgan’s building control charges. The charges apply from 1 April 2023. The charges include VAT.
Check before relying on it: the schedule is older than 2025 or undated, so check it is still current.
Private building control firms (registered building control approvers) 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
Vale of Glamorgan publishes one total fee in its own schedule. The loft figure is for a loft with a dormer; without one it is £562.50.
Planning
If your extension needs planning permission, a householder application in Wales costs £585. Many single-storey rear extensions are permitted development and need no application, and a lawful development certificate (£292.50) confirms it in writing.
Other councils in Wales
Building control for a 10 to 40 m² extension:
- Newport: £485
- Bridgend: £587
- Conwy: £648
- Gwynedd: £684
- Pembrokeshire: £780
- Ceredigion: £885.60
- 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 £57,000 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 a measured survey, design, a structural engineer, Vale of Glamorgan’s own building control charge and a 15% contingency, plan for £69,500 to £88,500.
How much is building control in Vale of Glamorgan?
Vale of Glamorgan’s own published charge for full plans approval of a 10 to 40 m² extension is £540 (including VAT). The charges apply from 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 £42,500 to £52,000 including VAT for the building work, and about £52,000 to £67,500 with fees, Vale of Glamorgan’s own building control charge 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
- When quotes arrive, check each one against the typical range for your area
Work in Vale of Glamorgan? Firm listings on Estiquote’s map of checked local firms open soon: see what you’ll need. Listing will be free while we build the map, with at least 30 days’ notice before any charge.