In short: An HMO extension adds space to a shared house, usually a ground-floor bedroom with ensuite or a bigger communal kitchen. We carry this out across Belfast, priced against the HMO rules for Northern Ireland and the council’s own standards.
- Nation
- Northern Ireland
- Pricing region
- Northern Ireland
- Postcode areas
- BT
- Main towns
- Belfast, Newtownards, Dundonald
What do extensions for extra rooms in Belfast involve?
- Fire separation and detection extended to the new space
- Heating, insulation and glazing
- Foundations, structure and roof
- Planning route check and drawings
- Ensuite drainage and extraction
- Kitchen or bedroom fit-out
Which rules apply in Belfast?
- All new HMOs need planning permission; councils such as Belfast apply HMO policy areas and limits on concentration.
- New HMOs need building control approval as well as planning permission.
- The NIFRS HMO Fire Safety Guide (July 2026) usually expects Grade D1 interlinked detection in smaller shared houses and a Grade A system with more than 6 occupants or over 200 m².
- Kitchens, bathrooms and WCs must meet the 2019 living accommodation standard regulations and licence conditions.
- Doors on protected routes are typically FD30 or FD30S, self-closing on three hinges; emergency lighting is required in HMOs of 4 or more storeys.
How much do extensions for extra rooms cost in Belfast?
| Item | UK typical | Local guide | Per |
|---|---|---|---|
| Single-storey extension, about 15 m² | £35,000 – £60,000 | £31,500 – £54,000 | project |
| Single-storey extension per m² | £1,800 – £4,000 | £1,600 – £3,600 | 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 Belfast
Questions about extensions for extra rooms in Belfast
Will the extension affect neighbours?
Possibly, if it is on or near a boundary. Party wall procedures may apply in England and Wales.
Can I extend an HMO under permitted development?
Some extensions to houses are permitted development, but rules differ for HMOs and by nation and council. We check the address before design.
Do you carry out extensions for extra rooms across Belfast?
Yes, across the whole of Belfast, including Belfast, Newtownards, Dundonald.
Who licenses HMOs in Belfast?
HMO licensing in Belfast, as everywhere in Northern Ireland, is run by the NI HMO Unit at Belfast City Council. Planning and building control are handled by the local council.
Other HMO services in Belfast
- Loft conversions for extra rooms in Belfast
- Communal kitchen refits in Belfast
- Layout changes and room reconfiguration in Belfast
- Large HMO conversions (7+ sharers) in Belfast
- Ensuite installation in Belfast
- House to HMO conversion in Belfast
- Sound insulation in Belfast
- Shared bathroom and shower room refits in Belfast