Loft Insulation Upgrade in London

The problem

Julie contacted us because the upstairs of her home felt noticeably colder than the ground floor, particularly during the evenings. The heating was running for long periods, but the bedrooms still cooled down quickly once it was turned off.

During the loft survey, we found only a thin and uneven layer of old insulation between sections of the ceiling joists. Several areas had little or no insulation at all, meaning a significant amount of heat was able to escape through the loft.

The loft also had no usable storage area, with belongings previously placed directly across the joists and old insulation.

Our assessment

The loft had a floor area of approximately 38m², while the pitched roof sections measured approximately 48m². We recommended insulating both the loft floor and the roof pitch to improve the overall thermal performance of the space.

The proposed installation included 100mm Knauf mineral wool across the loft floor, SF19 SuperFOIL insulation across the 48m² pitched-roof area, and 10m² of raised loft boarding for safe and practical storage. It also covered the removal and repositioning of loose debris and damaged insulation, careful installation around cables, ventilation points and the loft hatch, and a final inspection and clean-up.

The installation

The existing insulation was checked and any unsuitable or heavily compressed material was removed.

We then installed 100mm Knauf mineral wool between the loft-floor joists, ensuring consistent coverage across the 38m² area. Particular attention was given to the edges of the loft, where gaps commonly allow heat to escape.

The SF19 SuperFOIL system was fitted across the 48m² roof pitch. The material was secured carefully across the rafters, with joints overlapped and sealed to create a continuous insulation layer.

A 10m² raised boarding area was then installed, giving Julie a stable storage platform while helping to prevent the new floor insulation from being compressed.

The result

The finished loft has a continuous, even insulation layer across both the floor and the pitched roof, with the eaves kept clear and the belongings back on a proper storage platform. Julie reported that the upstairs rooms now hold their heat for noticeably longer and feel more comfortable on colder evenings, and that the new boarding gives her practical storage without pressing down on the insulation below. It is a good example of how treating the loft floor and the roof pitch together — rather than just topping up the floor — can make a real difference to comfort in an older terraced home.