Basement and cellar conversions in Holywood

Covering Holywood

Holywood sits 22 miles north of Downpatrick, with Newtownabbey 4 miles to the north-west and Belfast 5 miles to the south-west.

Homes in County Down

Housing in Northern Ireland mixes terraces in Belfast and Derry with detached houses and bungalows in towns and rural areas, many with room to extend.

What is included in a basement conversion in Holywood?

A basement conversion turns an existing cellar into dry, usable rooms, or excavates a new basement under a house. Converting an existing cellar is far simpler and cheaper than digging a new one, and often does not need planning permission.

Planning and building control applications to the council
Damp and structural survey
Underpinning or lowering the floor where needed

How much does a basement conversion cost in Holywood?

Use these ranges to budget for basement and cellar conversions; the survey turns them into a fixed price for the agreed specification.

Basement and cellar conversions	Guide price incl. VAT
Existing cellar conversion	£1,900 to £3,000 per m²
New basement excavation	£4,200 to £6,600 per m²

Do you need permission for a basement conversion in Holywood?

In Northern Ireland the council handles both planning and building control. Permitted development rules are set by the Planning (General Permitted Development) Order (Northern Ireland) 2015, and there is no party wall act, so we agree access and protection with neighbours in writing.

In Northern Ireland new basements and external changes normally need planning permission; building control approval is needed.

What can change the price or programme?

Groundwater levels drive the waterproofing design and cost.
A pump for the drainage system needs a battery back-up.

What happens after I enquire?

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.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Your questions answered

How much does a basement conversion cost?

Converting an existing cellar costs about £1,900 to £3,000 per square metre including VAT. A new excavated basement is around £4,200 to £6,600 per square metre.

How do you keep a basement dry?

With a designed waterproofing system, usually a cavity drain membrane draining to a pump, sometimes combined with tanking.

Can you visit a house in Holywood to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Basement and cellar conversions near Holywood

Learn more about basement and cellar conversions, or see every project we cover in Holywood.