Are you insulating an unvented attic?
Per Johns Manville.........
Proper Installation Proper installation occurs directly under a sloped roof deck over an unvented attic space where no soffit, eave, gable, or ridge vents are installed in the roof.1 Also, in an unvented attic, the eaves and roof deck are air-sealed, rather than the attic floor. Insulation is then installed up to the bottom of the roof deck. When securing the batts to the roof deck it is critical that the batts be held firmly up against the roof, with minimal compression of each batt and minimal gaps between batts.
For this application, the roof framing is typically truss construction, with 2x4 or 2x6 truss top chords. Unfaced fiberglass batts are required with 24” full width product to cover the framing member. Typical thicknesses and R-values for this application are: • R-30 – 10¼” • R-38 – 13” • R-49 – 13 1/2”
Benefits of JM Fiberglass Batt Installation for Unvented Attics
• No special training required • Familiar materials and installation practices • Fewer installation steps than other air permeable insulation options • QII installation easily achieved This time-tested method is currently used for underfloor and commercial roof insulation installations with the addition of a different spacing pattern for straps.
No comments:
Post a Comment