Insulation For Between Roof Rafters

7 staple sheets of 6 mil plastic over unfaced insulation to create a vapor barrier.

Insulation for between roof rafters. When you use solid insulation board to create a warm loft the key thing to remember is ventilation you must keep a 50mm gap between the roof and the rigid insulation board. The general advice we give is that you should always insulate between and above the rafters or between and under the rafters on our u value calculator we don t give an option for putting insulation between the rafters. Being lightweight they do not impose significant additional loads on existing structures. In this blog post we will be looking at insulating pitched roofs and why putting insulation just between the rafters isn t a viable solution.

We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe. Where the insulation does not fill the total rafter depth the low emissivity foil facings can gain additional thermal benefit from the air spaces they face. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.

It allows insulation to be installed in a watertight roof either after the roof covering has been fixed on a new build or without disturbing an otherwise sound existing roof covering as part of a renovation. Once up at roof level the between rafter boards can be cut accurately to fit the rafter spacings.