How To Insulate Between Roof Rafters

How to install rafter insulation.

How to insulate between roof rafters.

First climb into the attic and use measuring tape to determine the square footage of the space. For a ventilated roof fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces. Cut each piece of insulation an inch or two longer than needed to assure a snug fit. Attach baffles to the bottom of the roof sheathing the plywood or solid wood strips onto which roofing material was installed.

Step 1 measuring the space. Step 2 cutting and fitting the insulation. Your rigid boards will need to be cut to fit the gaps between the rafters. Again make sure you select the right thickness of the material so you fill as much of the rafter gap as possible.

Measure the space between the rafters where the insulation will be placed and cut the insulation boards marginally wider than the space to ensure a friction fit upon installation. How to insulate roof rafters. Use your straightedge to compress the insulation before cutting and use a very sharp utility knife to assure a good straight cut across the fiberglass batt. Step 3 installing the insulation.

Isover glass mineral wool gmw is another option for the between rafter insulation as a roll or batt. 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. If your attic is going to be converted into livable space then you will need to insulate the roof rafters.

Once you have these in place measure the length of the spaces between your rafters. Using rigid boards as opposed to wool is a much more precise. The flexible nature of gmw means that the roll or batts can be accurately cut and friction fitted between the rafters thereby minimising air gaps and maximising thermal performance. Don a long sleeved shirt safety glasses gloves and a dust mask to prevent irritating fiberglass from reacting with.

You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. When they are cut ensure there is a.