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County Down · Northern Ireland

Underfloor insulation in County Down

Underfloor insulation across County Down, survey-first: a written result for every wall and a fixed price before work. Underfloor insulation fits mineral wool or rigid boards between the joists of a suspended timber floor, supported on netting or battens, so cold air from the ventilated void below stops chilling the room.

Lifted floorboards showing insulation fitted between suspended timber floor joists

Free survey in County Down

Tell us about the property and we will arrange a free survey and a fixed price.

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We use your details only to answer this enquiry and arrange your visit, sharing them only with the registered installer we appoint for your job and the providers named in our privacy notice. No marketing lists, no cold calls.

Underfloor insulation across County Down

We cover 5 towns in County Down: Bangor, Newtownards, Newry, Downpatrick and Banbridge.

Small measures like this are often among the cheapest per pound saved, and they suit County Down homes of every age. In County Down homes this is often done on the same visit as a cavity fill, which saves a second trip.

Building control in Northern Ireland

In Northern Ireland, inserting insulation into an existing cavity wall needs a building control application to your council before the work. We make sure the application route is agreed and confirmed in writing before any drilling starts.

Funding in Northern Ireland

  • The Affordable Warmth Scheme, run with the NI Housing Executive, helps owner-occupiers and private tenants with a total gross household income under £23,000; cavity wall insulation is a priority measure where suitable.
  • The NI Sustainable Energy Programme funds energy efficiency schemes through participating providers.
  • ECO4 does not apply in Northern Ireland.

Sources: Building Control NI: frequently asked questions; Belfast City Council: what are the building regulations; NI Housing Executive: Affordable Warmth Scheme; Utility Regulator: NI Sustainable Energy Programme.

Keeping the void ventilated

Air bricks under a suspended floor must stay clear so the timbers stay dry. Insulation goes between the joists, not across the void, and gaps at skirtings are sealed to stop draughts.

What is included

  • Floor void inspection
  • Insulation between joists
  • Draught sealing at skirtings
  • Boards relaid

Underfloor insulation prices in County Down

Underfloor insulation guide prices
Underfloor insulation guide pricesGuide price
Suspended timber floor, typical room£795–£1,495
Whole ground floor£1,995–£3,995

No VAT is charged on installing insulation in homes until 31 March 2027 (then 5%). Guide ranges only: the fixed price is confirmed in writing before any work starts, and anything that could not be seen at survey is agreed with you first.

What happens next for a County Down property:

  1. Tell us about the property

    Postcode, property type and what you would like done.

  2. Free survey

    Access, condition, existing insulation and ventilation checked.

  3. Written result and price

    What we recommend and a fixed price before any work.

  4. Work and tidy-up

    Fitted at an agreed time, with ventilation kept clear.

Last reviewed 19 October 2026.

Underfloor insulation in County Down: questions

Do you cover all of County Down?

Yes. We cover 5 towns across County Down, including Bangor, Newtownards, Newry and Downpatrick, and the villages around them. Island and remote addresses are surveyed by arrangement.

Can you do this on the same visit as cavity wall insulation in County Down?

Often, yes. If your County Down home also has unfilled cavity walls, both can be surveyed together and priced separately on one quote.

How much does underfloor insulation cost in County Down?

Our guide ranges for underfloor insulation are shown on this page. The fixed price for your County Down property is confirmed in writing after the survey, before any work starts.

Do you cold-call in County Down?

No. We only come out when you have asked us to. If someone cold-calls offering free insulation, check before you agree to anything.

Underfloor insulation in nearby areas

Book a free survey in County Down

Free survey with an install quote. Written result. Fixed price before any work.