When insulating at ceiling level, glass mineral wool is commonly used. This is an inexpensive, yet efficient way of increasing the thermal performance of a loft space. 270mm-300mm will achieve current regulations. For ‘room-in-roof’ applications the insulation follows the roof pitch. A number of options are available depending on rafter depth and available head height. Invariably the solution will involve two layers of insulation, one between, the other below rafter line. Some manufacturer’s solutions can be costly, but with GEC advice we will help you to steer clear of these.