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County Down · Northern Ireland

Cavity insulation top-up in County Down

Cavity insulation top-up across County Down, survey-first: a written result for every wall and a fixed price before work. A cavity top-up fills voids left by an older installation: missed panels around windows, settled fibre, areas disturbed by an extension or new window.

Technician inserting a borescope camera probe into a small hole in a buff brick wall

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.

Cavity insulation top-up across County Down

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

Exposure matters for every cavity wall. Parts of County Down face some of the heaviest wind-driven rain in the UK, especially exposed coastal and upland sites. Here the survey is stricter: some walls suit only certain certified systems, and some should not be filled at all.

County Down properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. Most County Down houses built from the 1920s onwards have cavity walls, but the survey still checks each one: cavity width, debris, the condition of the brickwork and how exposed each wall is.

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.

How do I know if my walls need a top-up?

Cold patches on internal walls, a thermal image showing uneven heat loss, or an EPC that says 'filled cavity' when parts of the house feel colder are all signs. Extensions are a common cause: the new wall is insulated as built, but the old wall it joins may have been left partly empty.

What is included

  • Borescope survey at several points
  • Map of filled and empty sections
  • Targeted fill with a compatible system
  • Making good
  • Written result with photos

Cavity insulation top-up prices in County Down

Cavity insulation top-up guide prices
Cavity insulation top-up guide pricesGuide price
Detached house£1,295–£2,295
Semi-detached house£795–£1,495
End-terrace house£695–£1,295
Detached bungalow£695–£1,295
Semi-detached bungalow£595–£995
Mid-terrace house£595–£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.

From enquiry to finish in County Down:

  1. Send your details

    A minute online, or call the free number.

  2. We check the walls

    Construction, cavity width, debris, damp and wind-driven rain exposure.

  3. You decide

    Plain-English result and a fixed price, with no pressure to book.

  4. Job done properly

    Holes made good, paperwork handed over, guarantee details confirmed.

Last reviewed 19 October 2026.

Cavity insulation top-up 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.

How soon can you visit in County Down?

We arrange dates when you get in touch. Availability varies through the year, so we give you real dates rather than a promise on the website.

Is there VAT on cavity insulation top-up in County Down?

Installing insulation in a home is currently zero-rated for VAT until 31 March 2027, then 5%. Commercial buildings are standard-rated.

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.

Cavity insulation top-up in nearby areas

Book a free survey in County Down

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