Loft Insulation Case Study — Raised Central Walkway With 300mm Insulation Either Side, Basingstoke

The problem

Laura wanted to keep the central walkway for access to stored items and roof services, but the lack of insulation on either side was making the upstairs noticeably colder.

The walkway itself was useful, yet most of the ceiling area remained exposed. This meant the loft still performed poorly despite having a practical access route.

Our assessment

The unboarded loft floor measured approximately 35m². The raised walkway could remain in place without compressing the new insulation. We recommended 300mm of Knauf glass mineral wool on both sides, with 100mm between the joists and 200mm cross-laid above.

The installation

The first layer was fitted between the joists from the walkway out towards each eave. Rolls were cut neatly around the walkway supports and blockwork junctions.

The 200mm top layer was installed across the joists on both sides, finishing flush with the raised board edges. The walkway remained clear and fully usable, while the eaves ventilation route was preserved.

The result

The loft retained its central access route and gained full-depth insulation across the surrounding floor. Laura reported that the bedrooms felt warmer without losing the practical storage and maintenance access provided by the walkway.