Replies

1. 
   DanH | Jun 05, 2013 03:29pm | #1

   1) You should tell us where (what climate) this house is.

   2) Millions of homes across the US have cellulose in the ceiling, with no vapor barrier.  The vast majority have no problems due to this.  It's only apt to become a problem if the attic is very poorly ventilated.

1. 
   laocui | Jun 05, 2013 04:13pm | #2

   The house is 50's split level   in Montreal, Quebec, Canada. I put about R50 cellulose in attic  last year . I thought the old paint might serve as vapor barrier , but not . I  suspect there are some chemical in cellulose come down from ceiling which cause me coughing .  So I  think put a vapor barrier + second drywall.

1. 
   DanH | Jun 05, 2013 05:48pm | #3

   If the ceiling is intact and doesn't have any serious holes in it there should be nothing "coming down" from the ceiling.  You can certainly add the VB and extra rock, but I think it's a waste of time.

   If you feel you need a better VB, look into VB paint.

2. 
   DanH | Jun 06, 2013 11:52am | #4

   The bubbles were due to poor paint adhesion, possibly from putting oil over latex.  Worst case due to "milk paint" in an older layer.

3. 
   laocui | Jun 06, 2013 02:47pm | #5

   Thanks for the information and advice .