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Chelmsford · Installed 14 January 2026

Multifoil retrofit on a 1930s Chelmsford semi — loft rafters + garage ceiling

1930s semi · narrow cavity (no CWI possible) · self-funded retrofit

Mrs. Parekh had lived with a bedroom-above-garage that went uninhabitable every January since she bought the house in 2019. The original loft insulation had been compressed flat under years of storage boxes, and a prior cavity-wall survey had come back negative — the 1930s brickwork cavities were too narrow for blown-bead insulation. Conventional retrofit options had run out. Multifoil was the answer.

Before / after

EPC band
D 58C 72

+14 points

Gas use
18,500 kWh/yr11,200 kWh/yr

-39%

Annual heating cost

~£620/yr saved

Install duration
2 days

Bedroom 4°C warmer

Why multifoil, and why here

The property is a CM2 semi with a small integral garage under the main rear bedroom. Two problems stacked on top of each other: a loft that was technically insulated but doing almost no work, and a garage ceiling that was the only thing between an unheated concrete space and a child's bedroom. Mrs. Parekh's surveyor priced a full quilt replacement, but depth between the rafters was tight and she didn't want to lose usable loft height.

Actis Hybris is a reflective multifoil system that hits a 150mm-equivalent U-value in ~35mm of real depth. That profile let us insulate between the rafters without sacrificing headroom, and the same product worked as a direct-fix application to the garage ceiling plasterboard.

What we installed

Two-day install. Day one: cleared the old compressed quilt, fitted Actis Hybris between every rafter in the main loft with the required 20mm air gap, sealed joins with the manufacturer-spec tape, and dressed the eaves. Day two: battened out the garage ceiling, ran a multifoil layer across the full span, and re-boarded with 12.5mm plasterboard for a flush finish.

No grant paperwork, no scheme eligibility — Mrs. Parekh self-funded the job. We invoiced against a fixed quote agreed at survey.

The outcome

Post-install EPC came back at C 72, up from D 58 — a full band jump driven by the combined loft and garage-ceiling measures. Metered gas use dropped from 18,500 kWh in the prior year to 11,200 kWh over the first 12 months post-install, a 39% reduction. At current unit rates that puts the annual saving at roughly £620.

The bedroom above the garage now holds 18-19°C on the coldest nights, measured with a logged thermometer over the first winter — up from 14-15°C the year before. Mrs. Parekh's daughter has moved back into the room.

The bedroom above the garage used to be unusable in January — now my daughter actually wants to sleep in there. The team was in and out in two days and left everywhere spotless.

Mrs. Parekh, Chelmsford

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