Cavity wall insulation for Belfast properties
Belfast is among the towns we cover in County Antrim, alongside Newtownabbey, Lisburn and Carrickfergus. Belfast is one of the main towns we cover in County Antrim.
If a wall in Belfast is not suitable, for example because of an undiagnosed damp patch or a very exposed gable, you are told so in writing with the reason. 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.
Wind-driven rain is the first thing the surveyor weighs up. 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.
On the rules side, 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.
What happens on the day?
Holes of around 22mm are drilled in the mortar joints in a set pattern, roughly a metre apart. The insulation is blown in from the bottom up until each section is full, then every hole is filled with colour-matched mortar. Air bricks and flues are protected, and a cavity barrier is fitted where your wall joins a neighbour's.
What is included in Belfast
- Drilling, filling and colour-matched making good
- Borescope check where the cavity is in doubt
- Suitability survey with photos and a written result
- Certified mineral wool or bonded bead system
Guide prices for Belfast
| Cavity wall insulation guide prices | Guide price |
|---|---|
| Detached house | £2,295–£3,795 |
| Semi-detached house | £1,495–£2,495 |
| End-terrace house | £1,295–£2,195 |
| Detached bungalow | £1,295–£2,195 |
| Semi-detached bungalow | £895–£1,595 |
| Mid-terrace house | £795–£1,395 |
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.
The steps for cavity wall insulation 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.