How To Insulate Between Roof Rafters

First climb into the attic and use measuring tape to determine the square footage of the space.

How to insulate between roof rafters.

When they are cut ensure there is a. Again make sure you select the right thickness of the material so you fill as much of the rafter gap as possible. 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. 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.

Step 2 cutting and fitting the insulation. Step 3 installing the insulation. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. Cut each piece of insulation an inch or two longer than needed to assure a snug fit.

For a ventilated roof fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces. Isover glass mineral wool gmw is another option for the between rafter insulation as a roll or batt. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.

Attach baffles to the bottom of the roof sheathing the plywood or solid wood strips onto which roofing material was installed. 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. How to insulate 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.

Once you have these in place measure the length of the spaces between your rafters. 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. Your rigid boards will need to be cut to fit the gaps between the rafters.

If your attic is going to be converted into livable space then you will need to insulate the roof rafters. Step 1 measuring the space.