1930s semi nearly doubles heat-retention time after spray cork retrofit

The challenge

EPC rated D (60), with solid brick walls, no insulation and failing render to the rear extension. Conventional 100–150 mm EWI would have covered exposed brickwork detail and forced removal/reinstatement of every window. The owners needed a thin, breathable, evidence-backed solution.

Our solution

Existing failed render hacked off, brickwork repaired and primed, then 6–8 mm of CorkSol SprayCork applied over the prepared substrate by approved applicator JMB Plastering Specialists. Existing monocouche elsewhere was simply over-sprayed — no demolition needed. Performance validated using HomeLINK environmental sensors recording at 15-minute intervals.

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Results

• Time to lose 1°C nearly doubled — from 28 minutes pre-retrofit to 53 minutes post-retrofit
• Heat-loss risk dropped from high in all three monitored rooms to medium in two and low in one
• Heat dissipation improved across every room — over 50% improvement in the worst-performing room
• Achieved without covering lower brickwork or removing windows