You or your installer can also lay insulation boards called ClimaFoam® along with an 18mm layer of chipboard deck on top to provide storage space. Click here to view.These insulation boards are made from extruded polystyrene and are designed to be placed on top of the ceiling joists instead of the glasswool insulation. ClimaFoam is a perfect solution for storage space in the ceiling space as they have high compressive strength and provide great thermal performance. You will need a ceiling hatch which is minimum 600mm wide. Having R-2.6 glasswool insulation installed between the joists plus a layer of 50mm ClimaFoam board with a chipboard deck laid top and bottom gives the same thermal performance as installing R-4.1 glasswool insulation and will eliminate most thermal bridges.