How To Insulate Between Roof Rafters

The general advice we give is that you should always insulate between and above the rafters warm roof or between and under the rafters cold roof.

How to insulate between roof rafters.

First climb into the attic and use measuring tape to determine the square footage of the space. Install ventilation baffles into the space between the rafters before you install the insulation usually by stapling into place. Using rigid boards as opposed to wool is a much more precise. Step 3 installing the insulation.

If your attic is going to be converted into livable space then you will need to insulate the roof rafters. 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. Step 2 cutting and fitting the insulation.

When they are cut ensure there is a. Attach baffles to the bottom of the roof sheathing the plywood or solid wood strips onto which roofing material was installed. Isover glass mineral wool gmw is another option for the between rafter insulation as a roll or batt. Your rigid boards will need to be cut to fit the gaps between the rafters.

Once you have these in place measure the length of the spaces between your rafters. For a ventilated roof fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces. Again make sure you select the right thickness of the material so you fill as much of the rafter gap as possible. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.

Step 1 measuring the space. Don a long sleeved shirt safety glasses gloves and a dust mask to prevent irritating fiberglass from reacting with. 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. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.

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. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.