Insulation Between Roof Rafters

For example if the space beneath the rafters is going to be used for a living area then you will need to insulate the roof rafters.

Insulation between roof rafters.

Unfaced insulation has no tabs and stays in place with friction between the fiberglass and the rafters. Whether you need to insulate your roof rafters will depend on what you intend to do in the space directly beneath the rafters. Common rafter depths range from 100mm to 200mm. 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.

You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. 7 staple sheets of 6 mil plastic over unfaced insulation to create a vapor barrier. Although there are many different. Once up at roof level the between rafter boards can be cut accurately to fit the rafter spacings.

Modern u value targets mean installing insulation between rafters only is rarely a viable option. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. Being lightweight they do not impose significant additional loads on existing structures. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.