Loft rafter insulation

 If your loft is not ventilated and is used as storage or an additional warm space, you will need to insulate between and either above or below the rafters (depending on the roof structure) as the rafters act as a thermal bridge.

Typically rigid insulation boards are fitted between the rafters until flush with the leading face of the timbers. A further layer of insulation boards are then secured on top of the fitted boards at right angles across the rafter edges.

 If you are converting a previously cold / ventilated loft space to a warm area, advice should be sought to avoid condensation ocurring within the roof system. Steps can be taken to prevent a build up of moisture but these edepend on the materials used in the construction of the roof.