Case study
Loft Insulation Case Study — Large Loft Brought Up to a 300mm Insulation Depth, Manchester
Facing high winter bills and a hard-to-heat upper floor, Rebecca's large 54m² loft had never been properly insulated. We installed a full 300mm Knauf glass mineral wool system for even, continuous coverage.
What we found
- •A large loft floor with exposed joists and no continuous insulation layer
- •Wide areas where heat could pass directly through the upstairs ceilings
- •A central hatch that needed to remain clear throughout the installation
- •Older timber framing that required accurate cutting and careful placement of each roll
The problem
Rebecca contacted us after receiving high winter energy bills and struggling to keep the upper floor comfortable. The house had a large roof space, but the loft floor had never been properly insulated.
Because the area was larger than a typical loft, the amount of unprotected ceiling surface was significant. The bedrooms and landing warmed slowly, then lost heat quickly once the boiler stopped running.
Our assessment
The loft floor measured approximately 54m². The structure was dry and suitable for a standard cold-roof insulation upgrade. We recommended a full 300mm system, consisting of 100mm Knauf glass mineral wool between the joists and 200mm laid across the top to reduce thermal bridging.
The installation
The loft was divided into sections so the team could work safely from the hatch towards the gable wall. The first layer was installed tightly between the joists, with smaller sections cut around trimmers and timber intersections.
The second layer was cross-laid across the entire floor. Particular attention was paid to the perimeter, the hatch opening and the areas beneath the lower roof slopes. The final depth was checked at several points before the loft was cleaned and inspected.
The result
The finished loft had a continuous 300mm insulation layer across the full 54m² floor. Rebecca reported that the upstairs rooms felt more even in temperature and retained warmth for noticeably longer during the evening.
The installation helped to
- Reduced heat loss across a large loft area
- Improved comfort across the bedrooms and landing
- Helped the property retain warmth for longer
- Reduced cold bridging through the ceiling joists
- Delivered a clean and consistent finished installation
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