Author Topic: Advice on Moisture Barriers for Existing Attic  (Read 893 times)

Mega

  • Stubble
  • **
  • Posts: 176
  • Location: Burlington, Ontario
Advice on Moisture Barriers for Existing Attic
« on: May 16, 2014, 05:49:59 AM »
Hello,

MMM's post about attic insulation motivated me to start thinking yet again about dealing with my attic. I live in a 1960s sidesplit in southern Ontario (359 summers, -15C winters).

The problem I have with adding more insulation to my attic is there is no moisture barrier between the ceiling and the attic. Tearing out the ceiling while living in the house is not an option, especially with a toddler and 2 month old baby.


So, I think I have two options:

1 - closed cell spray foam on the underside of the roof. This will bring the attic into the "building envelope. I could then removed and replace the existing blown insulation at my leisure. This removes any concerns about ice dams (happened this winter leading to water penetration into the house via a window!), as well as eliminating concerns about attic venting.

2 - Closed cell spray foam on the ceiling. I would first need to remove the existing insulation first. Attic venting / water penetration could still be a concern.


Other notes: attic likely has some level of active mold present... Realistically, all homes in the area likely have mold in the attic.
 

Thegoblinchief

  • Guest
Re: Advice on Moisture Barriers for Existing Attic
« Reply #1 on: May 16, 2014, 07:07:04 AM »
There shouldn't be moisture barrier between the ceiling and attic. Any visible air gaps should be sealed, which requires moving the insulation around, then  replacing and adding more if needed.

Depending on the roof material, you may need to improve venting. The attic is supposed to be hot in summer and cold in winter.