Condensation with metal nailing fin and protruding nails
jeuteneier
| Posted in General Questions on
I recently installed a vinyl slider that I had to make a nailing fin for. I made it out of thin metal and noticed it’s sweating. Temps right now are about mid 30s outside.
I also noticed one of my sheathing nails went in at a bad angle and is sticking into the gap above the door with a water drop on the end.
I was planning to spray foam the gap but not sure if I’ll just be trapping or redirecting moisture of if the foam will effectively stop the condensation.
Thanks!
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Replies
jeuteneier,
The nails and flange are sweating because the warm interior air is coming in contact with them and condensing. The solution to stop that happening is to use impermeable insulation between them and the interior so the dew point is moved into that insulation, and air can not travel to those metal elements. Foam away.
Thanks Malcolm. Glad for the confirmation. I always like to let the rain come and prove my flashing is sound so when I started seeing moisture inside I thought it was a bad flashing job. I might do a thinner round of foam to see if that clears up any moisture then fill in the rest.
I plan to use the low expanding foam but I also want to make sure I've got complete contact with the metal so there are no exposed pockets. Will the low expanding be "forceful" enough or is the red gap filler better (noting that I have to properly secure the frame to not expand during curing.
jeutenier,
A two layer approach so you can see the results sounds like a good idea.
I've never had any problem with low expansion foam not filling voids. Even it puffs up a bit. I find the high expansions stuff too hard to control in small voids.
Thanks.
If I do use higher expansion i plan to secure a strong board (or level) to the frame to control any movement. Excessive I know, but I'm pretty careful that way.
I'll probably just go low expansion though.
I'll let you know how it goes.