Insulating Roof With Rigid Foam And Fiberglass

Rigid foam r value.

Insulating roof with rigid foam and fiberglass.

A 1 1 2 inch thick sheet of rigid foam insulation has a r value of 7 5. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow. Rigid foam insulation creates a solid barrier between the inside and outside of your house acting as an obstacle in the way of heat and cold transfer. Affix rigid foam insulation to the attic side of the hatch or door.

Most local building codes require that rigid foam boards made from polyurethane or polystyrene be covered with a 15 minute fire rated thermal covering if they are used on the inside of the house. Insulated roof assemblies can be vented or unvented. For a less pricey approach you can install 2 in. To ensure that humid indoor air won t reach the cold rim joist the crack at the perimeter of each piece of foam and at any penetrations should be sealed with caulk or canned spray foam.

Of rigid foam and a layer of fiberglass insulation in warmer climates 2 in. Foamular extruded polystyrene xps rigid foam insulation offers foamular extruded polystyrene xps rigid foam insulation offers a comprehensive line of products choose the strength you need from 15 to 60 psi and exceptional moisture resistance. Rigid foam also can be installed above the roof sheathing in tandem with air permeable insulation between the rafters. Financially speaking this spray is a great option especially when you need to renovate your roof after the application.

There is also less waste with fiberglass insulation. Polyurethane spray foam metal roof insulation. Rigid foam boards used in ceiling insulation are often made of either cellulose fiber fiberglass polystyrene or polyurethanes. Most packs of rigid foam feature a higher r value per inch than cellulose fiberglass or cotton.

There are at least two good reasons why this approach makes more sense than installing the insulation under the roof sheathing. Rigid foam on roof sheathing with air permeable insulation between the rafters. The spray can be basically applied on top or bottom of the metal roofing surfaces. However not all rigid foam insulation packs are created equal.

Add weatherstripping around the perimeter and a. In this case the rigid foam can be thinner than when it s used alone. Rigid foam insulation tends to have a low to moderate r value per dollar compared to fiberglass. For example insulating a 10 square foot wall area to r 15 costs about 3 40 to 4 00 with fiberglass insulation while a comparable r value for rigid foam costs roughly 10.

Compared to the fiberglass batts this insulation is much better. Of foam may be enough. Fiberglass insulation is less than half the price of rigid foam insulation when calculated by r value per square foot. Products provide superior insulating properties.

Code specifies the minimum r value of the rigid foam layer.