Foam Insulation Roof Rafters

Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels.

Foam insulation roof rafters.

The foam was applied to the attic rafters and walls. When building my current home i was faced with a dilemma on how to insulate a bonus room that would be upstairs. Encapsulating the rafter or top truss chord roof framing members with spray foam will improve the energy efficiency of the attic space. A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.

It typically has 3 variations. Often the r value of fiberglass insulation is too low and requires the rafters to be retrofitted making foam board a better choice. You can also add rigid foam insulation under the rafters which adds r value and eliminates thermal bridging through wood rafters. I had spray foam insulation installed into a 55 year old house 5 years ago.

I live in the northeast. The previous four options are all used beneath the roof. Place a ridge cap over the ridge to hide the gaps. Rigid foam board is just above the roof deck or an exterior insulation option.

I still notice a smell permeating the upstairs of the house on hot days which is concerning over 5 years. Leave a gap on both sides of the roof near the ridge so air can escape. The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. Consider using high density r 30 batts which are as thick as r 25 batts but fit into 2x10 framing.

R value of 7 in 1 inch 97 closed cell foam. Get your kits the easy to use spray foam kit. Spray foam insulation that s convenient and easy to use. If you are adding foam insulation to your roof rafters you must also properly ventilate the area.

Build the rafters and secure the 5 8 inch cdx sheathing material. This is because the effects of thermal bridging are limited which also results in the elimination of melt lines on the roof surface in cold climates. Staple plastic or foam baffles to the roof sheathing near the eaves to keep the material away. Polyurethane or polystyrene spray foams can provide thorough coverage to roof rafters and attic walls in much less time than is needed for other materials.

For the same reason insulation shouldn t touch the roof s underside. Step 1 prepare the roof. Class i e 84 fire retardant meets building code spec. The best attic insulation.