You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters.
How to insulate between roof rafters.
Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.
Using rigid boards as opposed to wool is a much more precise.
Attach baffles to the bottom of the roof sheathing the plywood or solid wood strips onto which roofing material was installed.
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.
Cut each piece of insulation an inch or two longer than needed to assure a snug fit.
First climb into the attic and use measuring tape to determine the square footage of the space.
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.
Your rigid boards will need to be cut to fit the gaps between the rafters.
For a ventilated roof fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces.
Step 1 measuring the space.
Step 3 installing the insulation.
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.
Isover glass mineral wool gmw is another option for the between rafter insulation as a roll or batt.
How to install rafter insulation.
Again make sure you select the right thickness of the material so you fill as much of the rafter gap as possible.
When they are cut ensure there is a.
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.
Install ventilation baffles into the space between the rafters before you install the insulation usually by stapling into place.
Step 2 cutting and fitting the insulation.
Don a long sleeved shirt safety glasses gloves and a dust mask to prevent irritating fiberglass from reacting with.