Where the soffit is on view we advise the installation of a grid system to the soffit to which the insulation is screw-fixed rather than the conventional knock-ins. This allows a degree of adjustability which will overcome any imperfections in the decking system.
 
Most commonly required in basements and undercroft car parks where cold bridging is a problem. The most popular solution in modern construction is to install a laminated board to the underside of the slab to provide the insulation required. Products available include mineral wool/fibre slabs and Phenolic/PIR Foams. They are all available in different finishes ranging from foil facings to decorative rigid facing boards where aesthetics are an issue.