I'm not sure where that 122 lbs came from. Each pkg is only about 42 pounds. I have an older home(90 yrs) with only 2 x 4s for suport. I insulated my attic to R50 2 yrs ago & have had no problems. The ceilings are latthe & plaster & nothing has happened thus far. I wouldn't worry about the weight at all. This product is excellent

I've had the Comfortbatt & Safe N Sound both uncovered in my home for extended periods with no issues. I would presume it is very safe as the product states it is - "Children and Schools GreenGuard Indoor Air Quality Certified"

A vapor barrier or retarder is vital component of exterior walls. It controls vapor transmission and helps prevent condensation from forming inside the walls and ceilings of your home. Vapor barriers/retarders are particularly important in Canada, and in US states that experience winter temperatures below freezing.

Warm air inside your home has a higher pressure than the cold air outside. It also contains moisture. To equalize the difference in pressure, the warm air tries to escape through your walls. The vapor barrier or retarder is what prevents that from happening. Without it, the escaping warm, humid air would pass through the insulation and contact the cold outer wall surface, where it would condense and collect. The resulting build-up of water inside the walls has the potential to damage wall framing members and promote the development of mold.

This product is amazing. I've had my home inspected through the eco-energy rebate program & had no issues. The product is wonderful in everyway. I would never recommend using pink fiberglass insulation. I've insulated my attic(R50) bathroom & basement using comfortbatt, I also used safe N Sound in the divinding walls & ceiling in my basement. It is so easy to use & I've never had to worry about glass fibers floating around in the air. It is so easy to cut & work with.