Roxul For Roof Rafters

Providing high quality insulation between cathedral ceiling roof joists is an easy method of improving the overall energy performance of a building.

Roxul for roof rafters.

Exceptional dimensional stability and rated for extreme hail rockwool stone wool insulation roof boards have meet both the fm severe hail and the ul 2218a standard for impact resistance. Not only do we withstand hail damage but our roof boards maintain their bond to the roof membrane lowering the likelihood of a catastrophic roof failure. R value measures how well certain building insulation materials can resist heat. Other relevant factors include the type of wood being used for the rafters the size of the rafters and the load that the rafters need to support.

Code specifies the minimum r value of the rigid foam layer. Rigid foam on roof sheathing with air permeable insulation between the rafters. The higher the r value the greater the insulation performance. Rigid foam also can be installed above the roof sheathing in tandem with air permeable insulation between the rafters.

Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. Rafters are commonly spaced about 24 inches 61 cm apart. When determining how much insulation you need don t guesstimate calculate. In this case the rigid foam can be thinner than when it s used alone.

All roof rafters should be identical so follow the same steps to measure the plumb cut tail cut and birdsmouth cut. The spacing between rafters in a given building is part of the engineering calculations that determine the required structure of the roof.