Sloping ceiling insulation
Sloping ceilings in bedrooms and upstairs rooms have very high heat loss per square metre.
This is because they usually consist of a sheet of plasterboard, a 100mm ventilated gap between the rafters, then battens, felt and tiles. If you compare this to an 18-inch wall or 12 inches of loft insulation, it becomes clear how little insulating effect they have, making them responsible for the coldness you’ll often find in these rooms. As a minimum of 50mm ventilation is required between the rafters, taking down the plasterboard to insulate behind a sloping ceiling is very expensive and disruptive for little gain. There is another solution, however.
Our sloping ceiling insulation consists of thermal laminate boarding, a high efficiency insulation board with plasterboard attached which is applied to the underneath of the sloping ceilings by screwing through to the rafters.
Gaps around the edges are then filled and the whole area re-plastered. Because the extra material costs little more, 100mm thickness is recommended wherever possible but, if you are limited on head-room, 50mm is still effective.
Since this is labour intensive due to the plastering, sloping ceiling insulation is the fourth most cost-effective insulation measure after draught proofing, loft insulation and secondary glazing. However, it still offers an attractive return on investment in terms of money saved on heating bills, typically in the region of 10% return per year. So if you have covered the other areas first, this is a very attractive next step for warmth, efficiency and saving money.