Loft Insulation Case Study — Combined Insulation Upgrade With a T-Shaped Access Platform, Cardiff

The problem

Emma contacted us because the upstairs rooms warmed slowly and the landing felt noticeably colder than the ground floor. She also wanted to retain a safe platform around the loft hatch.

The survey found that the floor insulation had settled and no longer provided an even layer. The bare roof pitch allowed the loft to experience large temperature changes and made the existing insulation work harder.

Our assessment

The loft floor measured approximately 35m² and the roof pitch measured approximately 46m². We recommended topping the floor insulation up to 300mm, fitting SF19 SuperFOIL across the roof pitch and retaining the 7m² T-shaped access platform. The brick gable, ridge and eaves all required neat, continuous detailing.

The installation

The mineral wool was redistributed and topped up using Knauf glass mineral wool. A 100mm layer was fitted between the joists where required, with a 200mm cross-laid layer completing the 300mm build-up.

SF19 SuperFOIL was then installed across both slopes. The sheets were fixed across the rafters, overlapped and sealed, with the material cut around the ridge structure and finished neatly against the gable wall.

A caged floor light was positioned near the hatch during the work. The T-shaped platform was kept clear and the floor insulation was not compressed beneath the boards.

The result

The completed loft combined a consistent 300mm floor layer with a continuous SuperFOIL roof-pitch installation. The hatch platform remained practical and the upstairs rooms held their temperature for longer after the heating was switched off.