Insulating at ceiling level provides the most cost effective insulation solution in terms of ratio of cost to energy saved. It is possible to achieve very high levels of insulation in pitched roofs where the insulation is positioned at ceiling level because the insulation thickness is largely unrestricted by construction considerations.
To avoid thermal bridging the roof insulation should butt up to or lap the wall insulation. The designer should consider at what stage this ‘linking’ insulation is installed, as this will affect the detailing of insulation at the eaves.
In cold roofs, one way of achieving this in practice is to place a short length of insulation quilt over the wall plate (and cavity closer, where applicable) immediately before the tiling underlay is fixed. This avoids having to push the insulation into place from inside the roof once the roof covering has been completed.
Earthwool Loft Roll 44 or 40 is installed in two layers, the first layer between the joists and the second layer across the joists. This minimises thermal bridging through the ceiling joists.
Earthwool Loft Roll 44 and Earthwool Loft Roll 40 are made from glass mineral wool and formed into rolls which are lightweight, flexible, resilient and non-combustible, their manufacture has a very low impact on the environment.