Loft Insulation Case Study — SuperFOIL Roof-Pitch Installation Above an Existing Central Walkway, Reading

The problem

David wanted to improve the performance of the loft without removing the existing walkway or disturbing the mineral wool below. The upstairs rooms were reasonably warm while the heating was running, but the house still cooled faster than expected overnight.

Although the floor insulation was broadly adequate, the exposed roof pitch allowed the loft temperature to follow outdoor conditions closely. This made the space uncomfortable to access and increased the risk of large temperature swings around stored items.

Our assessment

The loft floor measured approximately 36m² and the pitched roof area measured approximately 44m². The existing 300mm Knauf floor insulation could be retained. We recommended installing SF19 SuperFOIL across the full roof pitch while preserving the central walkway, the gable window, the hatch and the ventilation routes at both eaves.

The installation

The existing floor insulation was checked, lightly repositioned where necessary and protected with temporary boards. The central walkway remained in place throughout the work.

SF19 SuperFOIL was installed progressively from one eave to the ridge and then down the opposite roof slope. The sheets were tensioned across the rafters, overlapped at the joints and sealed with compatible tape.

Careful cuts were made around the gable window, ridge timbers and electrical cable. The long LED work light was moved between sections so the fixing and sealing could be checked clearly.

The result

The loft retained its clear central walkway and existing floor insulation while gaining a continuous SuperFOIL layer across the roof pitch. The completed space felt more stable in temperature and considerably cleaner and brighter because of the reflective internal finish.