Insulation Above Suspended Ceilings- Revisited

This issue has been covered before on this forum, but perhaps advances in insulating products may have changed the outlook for using batts with a vapor barrier. Johns Manville makes a product which covers this application and is available in 2’x4’ R30 Batts.

The link to their PDF application sheet is at:

Quote from the sheet is below:

ComfortTherm insulation carries a Class A rating (ASTM C 665) for low flame spread and has been classified FHC 25/50 by Underwriters Laboratories, meaning it can be used for some exposed (not covered by gypsum wallboard) applications where permitted by the local building code. See National Evaluation Service, Inc. (NES) Report No. NER-549 – copies available upon request. Under some conditions, even low flame spread material can burn at a slow rate if exposed to an open flame or other heat sources. Do not use ComfortTherm insulation where encapsulation film will be exposed to sunlight or mechanical abuse.

New Construction
• Wood frame construction – residential homes and light commercial buildings
• Metal frame construction – commercial buildings
• Pre-manufactured homes – modular or manufactured housing
• Suspended ceiling systems – sized to fit above 2 x 4 ceilings
• Interior wall sound control – interior walls and floor and ceiling assemblies (For sound class ratings for wall assemblies, see the appropriate STC values datasheet for either steel or wood framing.)"


I would like to know whether this could be used for single story residential application? I am insulating and finishing my garage and shop and have plenty of height to install a suspended ceiling. There is no living area over the garage.