What we check
Existing depth and condition, ventilation at the eaves, water tanks and pipes that need insulating, downlighters that need covers, and storage boarding that needs raising so insulation is not crushed.
Northern Ireland note
In Northern Ireland, councils treat roof-space insulation as work that needs building control approval. We confirm the route before work.
What is included
- Depth and ventilation check
- Mineral wool to the recommended depth
- Tank and pipe lagging
- Loft hatch draught-proofing
Loft insulation prices
| Loft insulation guide prices | Guide price |
|---|---|
| Loft insulation to 270mm, typical house | £395–£895 |
| Loft top-up from 100mm | £295–£595 |
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.
Rules and funding by nation
The building regulations route and the funding schemes differ between England, Wales, Scotland and Northern Ireland. The local pages for your area explain the rules where you are; in short:
- England: Filling a cavity is notifiable building work and needs a building notice or competent-person self-certification.
- Wales: Filling a cavity is notifiable work under the Building Regulations as they apply in Wales, usually self-certified through a competent person scheme.
- Scotland: No building warrant is needed for insulation within a wall, but the work must meet the building standards.
- Northern Ireland: Inserting cavity wall insulation needs a building control application to the council before work starts.
Sources: Energy Saving Trust: cavity wall insulation; Planning Portal: cavity wall insulation and building regulations; Welsh Government: building work competent person schemes; HMRC: VAT on energy-saving materials (Notice 708/6).