Over 20% of heat in a building is lost through the roof. Adding insulation to your roof is one of the most effective energy saving measures you can take – particularly with pitched roofs. In fact, insulating loft spaces in a building could reduce heat loss by 25%, providing a payback in 1-4 years. You can also upgrade existing insulation in most lofts by adding to what is already there (providing it is in good condition and not damp). If there is less than 15cm of insulation, it is worth adding more.
There are several types of insulation which may be suitable for different methods of insulation. These include mineral wool, sheep’s wool, blown insulation, and rigid insulation board.
For loft insulation, we'd recommend 350mm thickness, ideally in two layers at 90 degrees to each other. Make sure the loft space above can still breathe to avoid moisture build up.