Cavity insulation top-up for Belfast properties
We cover Belfast and the BT1 postcode district, including nearby Newtownabbey, Lisburn and Carrickfergus. Belfast is one of the main towns we cover in County Antrim.
Most Belfast 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. For semi-detached and terraced homes in Belfast, cavity barriers are fitted where your wall meets your neighbour's so the fill stays on your side.
Local weather affects which walls can be filled. Parts of County Antrim 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.
In terms of approvals, in Belfast inserting cavity wall insulation needs a building control application to the council before work starts.
Funding in Northern Ireland
In Northern Ireland, the Affordable Warmth Scheme helps eligible households with a gross income under £23,000.
Sources: NI Housing Executive: Affordable Warmth Scheme; Utility Regulator: NI Sustainable Energy Programme.
When a top-up is not enough
If the existing fill is wet, contaminated with debris or breaking down, adding more on top can make things worse. In that case we tell you the honest option, which may be partial or full removal and refill.
What is included in Belfast
- Making good
- Borescope survey at several points
- Written result with photos
- Targeted fill with a compatible system
Guide prices for Belfast
| Cavity insulation top-up guide prices | Guide 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.
How it works in Belfast:
Tell us about the property
Postcode, property type and what you need.
Free survey
Walls, cavity, condition and exposure checked and photographed.
Written result and price
Suitable, suitable after repairs, or not suitable, with a fixed price.
Work and paperwork
Installation, making good, and the regulations and guarantee paperwork.