Insulating wall cavity?

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  #1  
Old 12-19-19, 06:45 AM
J
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Insulating wall cavity?

Hello
I live in Canada with very harsh winters. My house was built in the 60ís. When I bought this house it was a flip. Hereís the problem. The guy took down all interior drywall and added strips on 2x4s to make 6 inch walls. His top plate was brought up to the existing ceiling tile (ceiling thatís stapled to plywood that was used instead of drywall). Some parts of the top plate are not tight against the ceiling. Then he put up a drop ceiling to cover ceiling tiles. Now my problem is that over the years with no air movement above drop ceiling one day I noticed damp ceiling tiles and some staring to get moldy in some spots along outside wall.
I put up ventilation tiles to get air moving which Helped. Now Can I use sprayfoam to fill in the cavityís? Will the foam hold moisture and condense on wall and ceiling?
i was thinking trimming of excess foam and tucking taping over it. I was also gonna take down drop ceiling strap roof with 2X3s then add drywall to cover old ceiling tile. Will the air cavity between new ceiling drywall and old tile condense?
Really need some help

Thank you
Jer
 

Last edited by Jeremym; 12-19-19 at 07:44 AM. Reason: Spelling error
  #2  
Old 12-19-19, 08:29 AM
P
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"...Can I use sprayfoam to fill in the cavity’s?" Which cavity are you referring to? Gaps at the top plate or the area between the old ceiling and newer drop ceiling?

Most foams will not hold moisture inside the foam. But, foaming one spot could cut off air circulation to an area and either help or hurt with condensation.

Whether or not a new sheetrock ceiling under the old tiles will condense depends more on other things like what's above. Is it attic or upstairs finished space? If it's attic it depends on how well the attic is insulated. Also affecting that little gap between ceilings will be airflow. Will air, say from gaps at the top plate, be able to get into that space or will it be sealed off well?
 
  #3  
Old 12-19-19, 09:44 AM
J
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Thank you for responding

i added insulation in the attic. I didnít get much at the ends by the soffit. No room to get in there. I was going to sprayfoam all around walls where it meet the ceiling. Then I was gonna trim excess foam with a utility knife. Use tuck tape to seal that then strap and drywall ceiling
Have hard time to post pictures.

thanks again

jer
 
  #4  
Old 01-28-20, 09:59 AM
J
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Cavity above top plate

Hello. The tiles in all corners of house were damp, plywood was also wet. Now That I removed tiles thereís a gap between top plate and plywood. I let plywood dry then added sprayfoam in gap. I removed some sprayfoam in the corner and plywood is damp again. Not as much or as bad when I removed tile. Should I just leave that gap and not fill it at all?
im gonna try to post a picture.

thanks
 
 

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