Roof Insulation Between Rafters

We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe.

Roof insulation between rafters. Unfaced insulation has no tabs and stays in place with friction between the fiberglass and the 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 boards creating the slope of the roof are wider than lumber used to build trusses 2x8s 2x10s and 2x12s are most common in rafters vs. In finished space insulation is placed between the rafter boards and drywall or other material is fastened to the face.

Water is insulation s enemy. Whether you need to insulate your roof rafters will depend on what you intend to do in the space directly beneath the rafters. 7 staple sheets of 6 mil plastic over unfaced insulation to create a vapor barrier. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.

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. 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. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be.

A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. 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. 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.

Although there are many different. Box out light fixtures. Insulation can be installed between the rafters using a ventilated roof construction or an un ventilated roof construction. The decision on which method to use is usually dependent on the sarking or underlay.

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.