How To Insulate Roof Rafters Properly

Your roof collects stubborn ice dams in the winter.

How to insulate roof rafters properly.

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. Cut each piece of insulation an inch or two longer than needed to assure a snug fit. For the same reason insulation shouldn t touch the roof s underside. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.

Read on to find out how to properly insulate. 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. How to insulate roof rafters.

You may have picked up these clues that you need better insulation or you ve merely seen the evidence when your energy bill shows up. With a warm roof the usual process is to split the insulation into two layers. Airspace from the soffit to the ridge by installing a continuous air chute in each rafter bay. To install the air chutes staple them directly to the roof decking.

If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters. First climb into the attic and use measuring tape to determine the square footage of the space. Step 2 cutting and fitting the insulation. To effectively ventilate your roof create a 1 in.

If your attic is going to be converted into livable space then you will need to insulate the roof rafters. Rigid foam board installation in the case of a cathedral ceiling involves installing three different layers that are each 1 5 inches thick according to the procedure discussed in this article appearing in fine homebuilding. Once you have these in place measure the length of the spaces between your rafters. Install ventilation baffles into the space between the rafters before you install the insulation usually by stapling into place.

Step 3 installing the insulation. Staple plastic or foam baffles to the roof sheathing near the eaves to keep the material away. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing. If you decided to use a rigid foam board to help insulate your cathedral ceiling you would install the board on top of the roof sheathing and underneath the plywood at the top of the roof.

Air chutes when combined with soffit vents and a ridge vent will help prevent problems with condensation and ice dams. The right way to insulate attics and cathedral ceilings with batts using certain t.