Basement & cellar insulation
Thousands of Greater Manchester terraces sit over a cellar, and a cold cellar means a cold ground floor. Insulating the cellar ceiling, or the basement walls where the space is lived in, fixes the coldest room in the house.
What it is
Where the cellar is unheated storage, insulation is fixed to the underside of the ground-floor joists — the cellar ceiling — using mineral wool or rigid boards with a vapour-control layer on the warm side. Where the basement is habitable, or the landlord wants it to be, the walls and floor are insulated instead, with a damp-proofing or tanking system designed alongside so moisture is managed rather than trapped. Both approaches bring the ground floor into the insulated envelope.
Why it matters for 2030
The EPC treats a suspended floor over an unheated cellar as an uninsulated floor, and that costs points on every cellared terrace in Salford, Bolton, Oldham and central Manchester. Cellar-ceiling insulation is a floor measure the assessor can see and record, and it is often cheaper and less disruptive than lifting floorboards for conventional underfloor insulation. Tenants notice the difference immediately in the living room.
Which homes suit it
Pre-1919 and inter-war terraces and semis with a full or partial cellar, and any property with a basement flat or converted lower-ground floor. The cellar must be reasonably dry; where there is standing water or active penetrating damp we deal with the cause first. Cellars with gas or electrical services running through the joists need the services made safe before insulating, which we include in the survey.
Grants that apply
Cellar-ceiling insulation qualifies as underfloor insulation under the Warm Homes: Local Grant for eligible Greater Manchester tenants and under ECO4 while it runs (to 31 December 2026). It is zero-rated for VAT until 31 March 2027. Tanking and damp-proofing works are not grant-funded and are priced separately. The grants page explains who qualifies.
How we do it
Surveyed and coordinated to PAS 2035 with a moisture-risk assessment on the cellar, then installed by our accredited partner LAMTANS Engineering to PAS 2030 standards and lodged with TrustMark. Ventilation to the cellar is maintained or added so the timber stays dry. You get a fixed price from our own price book and the evidence for your post-works EPC.
Common questions
Is insulating the cellar ceiling as good as insulating under the floorboards?
For EPC purposes it is the same floor measure, and in a cellared house it is usually the better option because nothing in the living space is disturbed.
Will it make the cellar damp?
Not if it is designed properly. The vapour-control layer goes on the warm side and the cellar keeps its ventilation, which is why it is done under PAS 2035 rather than as a DIY job.
Related: underfloor insulation · internal wall insulation · ventilation