Blown loft insulation
Blown loft insulation is loose-fill mineral wool fed through a hose and spread evenly across the loft floor to a set depth. It suits lofts with low pitches, tight eaves, irregular joists or lots of obstructions, where rolls are slow to fit without leaving gaps.
What is blown loft insulation?
The machine stays outside or on the landing and the hose runs up to the loft. Depth markers fixed to the joists or trusses show the installed depth, and the fibre settles into corners that rolls would bridge. We hold a board or tray at the eaves so the loose fill cannot block the ventilation path.
Is it right for your loft?
- Low-pitched bungalow or extension roofs where kneeling space runs out
- Lofts with trussed rafters close together
- Uneven or irregular joist spacing
- Lofts with many cables, pipes and obstructions
How we do it
- We check the loft, fix depth markers and set eaves trays in place.
- Cables are lifted, downlights covered and the tank platform marked out.
- The fibre is blown in passes from the far end back towards the hatch.
- We check the depth against the markers and top up thin areas.
- You get photos of the markers showing the installed depth.
What is included
- Loose-fill mineral wool to the agreed depth
- Depth markers left in place
- Eaves trays to keep ventilation open
- Hatch area finished with a retaining upstand
Worth knowing
Loose fill moves if the loft is used for access, so we leave a boarded walkway to the tank and any equipment. It is not suited to lofts you want to board for storage across the whole floor.
How much does blown loft insulation cost?
Installing insulation in a home is zero-rated for VAT until 31 March 2027 and 5% after that, under HMRC's rules for energy-saving materials (notice 708/6).
Do the rules differ across the UK?
Yes, a little. Building regulations and funding schemes are set separately in each nation. Here is the short version; each area page has the detail.
| Nation | Building rules | Funding to check |
|---|---|---|
| England | Approved Document L; insulation alone is not usually notified | ECO4 to 31 Dec 2026; Warm Homes Plan and Warm Homes: Local Grant |
| Wales | Welsh Approved Document L; conversions need building control | Warm Homes Nest; ECO4 to 31 Dec 2026 |
| Scotland | No building warrant normally needed; standards still apply | Home Energy Scotland grant and loan; Warmer Homes Scotland |
| Northern Ireland | NI Building Regulations (Technical Booklet F1); check with council building control | Affordable Warmth Scheme; NISEP |
Questions about blown loft insulation
Is blown insulation better than rolls?
It performs about the same for the same depth. It is the faster and neater option in lofts that are awkward to work in, and rolls are better where you want boarding later.
Does blown insulation settle?
Mineral wool loose fill settles a little, which is allowed for in the depth we install. The depth markers let you check it later.
Is it messy?
The hose runs through the house, so we sheet the route and the landing. The fibre stays in the loft.
Where we provide blown loft insulation
England
- Bedfordshire
- Berkshire
- Bristol
- Buckinghamshire
- Cambridgeshire
- Cheshire
- Cornwall
- County Durham
- Cumbria
- Derbyshire
- Devon
- Dorset
- East Riding of Yorkshire
- East Sussex
- Essex
- Gloucestershire
- Greater London
- Greater Manchester
- Hampshire
- Herefordshire
- Hertfordshire
- Isle of Wight
- Kent
- Lancashire
- Leicestershire
- Lincolnshire
- Merseyside
- Norfolk
- North Yorkshire
- Northamptonshire
- Northumberland
- Nottinghamshire
- Oxfordshire
- Rutland
- Shropshire
- Somerset
- South Yorkshire
- Staffordshire
- Suffolk
- Surrey
- Tyne and Wear
- Warwickshire
- West Midlands
- West Sussex
- West Yorkshire
- Wiltshire
- Worcestershire
Scotland
Often booked with it
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Sources, checked October 2026: Energy Saving Trust: roof and loft insulation; Which?: loft insulation costs and savings; LABC: building regulation requirements for loft insulation; GOV.UK: extending the ECO4 end date, government response.
