In short: An HMO extension adds space to a shared house, usually a ground-floor bedroom with ensuite or a bigger communal kitchen. In Carmarthenshire we survey first, price each item separately and hand over the certificates and photos a council asks for.
- Nation
- Wales
- Pricing region
- Wales
- Postcode areas
- SA
- Main towns
- Llanelli, Ammanford, Carmarthen
What do extensions for extra rooms in Carmarthenshire involve?
- Planning route check and drawings
- Building control completion
- Heating, insulation and glazing
- Fire separation and detection extended to the new space
- Ensuite drainage and extraction
- Party wall coordination where needed
Which rules apply in Carmarthenshire?
- More than 6 sharers is a sui generis HMO and needs planning permission; councils such as Cardiff apply concentration limits.
- Building regulations cover structural work, partitions, drainage, fire-resisting construction and electrics; confirm with building control whether the conversion is a material change of use.
- Council HMO standards and the fire risk assessment set detection, fire doors and escape routes.
- Kitchen and bathroom ratios are set in each council’s HMO standards.
Welsh councils set their own HMO standards and may run additional licensing. In Wales, changing a house to a C4 HMO always needs planning permission, so check planning first.
How much do extensions for extra rooms cost in Carmarthenshire?
| Item | UK typical | Local guide | Per |
|---|---|---|---|
| Single-storey extension, about 15 m² | £35,000 – £60,000 | £32,900 – £56,400 | project |
| Single-storey extension per m² | £1,800 – £4,000 | £1,700 – £3,750 | m² |
Typical time on site: 8–14 weeks. For a figure for your house, try the guide-price tool.
Extensions for extra rooms by town in Carmarthenshire
Questions about extensions for extra rooms in Carmarthenshire
Will the extension affect neighbours?
Possibly, if it is on or near a boundary. Party wall procedures may apply in England and Wales.
Is a kitchen extension worth it?
Often, when the existing kitchen limits how many people the council will allow. A bigger kitchen can unlock an extra room.
Do you carry out extensions for extra rooms across Carmarthenshire?
Yes, across the whole of Carmarthenshire, including Llanelli, Ammanford, Carmarthen.
Who licenses HMOs in Carmarthenshire?
Carmarthenshire council licenses HMOs in its area. Landlords must also register with Rent Smart Wales.
Other HMO services in Carmarthenshire
- Loft conversions for extra rooms in Carmarthenshire
- Communal kitchen refits in Carmarthenshire
- Layout changes and room reconfiguration in Carmarthenshire
- Large HMO conversions (7+ sharers) in Carmarthenshire
- Ensuite installation in Carmarthenshire
- House to HMO conversion in Carmarthenshire
- Fire alarm and detection systems in Carmarthenshire
- Void and between-tenancy refurbs in Carmarthenshire