Unvented roof assemblies should be insulated either with air impermeable insulation rigid foam or spray polyurethane foam or with a combination of foam and air permeable insulation.
Using roxul in attic.
Roxul rockboard 60 and 80.
They can be easily cut and even shaped.
With 2 layers between the joists and another layer running perpendicular over top the r value of the insulation in the side attic is in the range of r 40.
Whether you are building new or renovating your home use roxul comfortbatt thermal home insulation in your exterior walls attic ceiling and floor frames for top thermal performance.
The insulation used would depend on the constraints of the application space required r value as per building code etc.
The 2 8 floor joists allow for two layers of 2 4 insulation in between.
Roxul rockboard is rigid panels made for use in ceilings and floors as well as walls.
Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.
Please see our youtube channel for how to videos as well as the diy energy star guide for more information.
I chose to insulate with roxul which has a higher r value than the pink stuff.
In the 2nd area i would be using it on the attic floor with the rigid foam against the drywall ceiling and filling the rest with batt insulation then plywood for storage.
2 4 insulation has an r value of 13 5.
Use rockwool thermal stone wool insulation to insulate the attic of a new build extension or to increase the r value and top up the current attic insulation especially in an older home.
It not only provides a thermal barrier but also improves sound absorption and impact vibration and noise.
If you don t want to use sips or nailbase read this article tolearn the four basic approaches to insulating unvented roof assemblies.
With its high density non directional fiber structure and unique flexible edge roxul comfortbatt is designed to deliver a better fit providing heating and cooling energy savings.
Roxul is made from mineral wool spun from molten basaltic and igneous rock.
I would leave the attic as unconditioned space but hopefully increase the r value and reflect radiant heat gains in the summer.
We recommend the use of rockwool comfortbatt to insulate an attic.
Be sure to use a vapour control layer when required.