Insulating the loft and under the floor
In 2023 the loft was topped up with insulation and boarded, and the cavity under the ground floor was insulated. Neither can be seen from the rooms. The homeowner feels the house now holds its heat much better, though nothing has been measured.
The loft
In August 2023 the loft was insulated and boarded, for £2,380. Earthwool insulation was added: a 170 mm layer over the part of the loft that is not boarded, and a 100 mm layer under the boarded part. The boards form a floating floor, laid on 96 by 44 mm joists that sit on the house's own joists. The old hatch was removed and the opening sealed with plasterboard. A new hatch was built in a different place on a reinforced frame: insulated, draught-proofed, made of uPVC and fitted with a multi-point lock. A 2.9 m telescopic aluminium ladder now reaches it.
Under the floor
In November 2023 the cavity under the ground-floor main part of the house was insulated for £2,745, with 100 mm INDITHERM insulation batts, fitted by hand. You cannot see this work, because it is under the floorboards. That is why this story is also found in the living room.
How the house feels
The homeowner feels the house holds its heat much better since the underfloor and loft insulation went in. There are no measurements to back the feeling, and no before-and-after temperatures or energy figures.
The specification
Underfloor: INDITHERM insulation batts, 100 mm thick, 100 by 370 by 1200 mm each, sold four to a pack covering 1.78 square metres. Loft: a 170 mm top-up layer of Earthwool insulation over the unboarded area and a 100 mm top-up layer under the boards (the total depths are not recorded); boarding on 96 by 44 mm joists; an insulated, draught-proofed, maintenance-free uPVC hatch with multi-point locking; and a 2.9 m telescopic ladder in anodised aluminium with three lengths, automatic locking and release, extra-wide steps, rubber feet and a 150 kg limit.
Benefits
- The house feels as though it holds its heat much better, in the homeowner's own experience (not measured).
- A boarded loft reached by an insulated, draught-proofed hatch and a ladder.
Limitations
- There are no measurements before or after: the warmer feeling is the homeowner's impression.
- The costs are the totals on the quotations, one house's prices, and there was no grant.
- Nothing here is a promise of comfort, saving or payback for another home.