Insulation above bathroom vent

   / Insulation above bathroom vent #1  

thatguy

Elite Member
Joined
Mar 1, 2005
Messages
2,808
Location
Bedford, VA
Tractor
John Deere 2320
We got a very light snow a while back and I noticed there was a 18"x 18" spot on our hip roof that was not snow covered.. From the attic I can see that the spot is right above a halfbath exhaust vent/light and there was no insulation covering the vent ..

Should there be insulation covering this vent?

Brian
 
   / Insulation above bathroom vent #2  
Is this a fan/light combination?

Most of these fixtures are rated for contact with insulation.
You will want to make sure it is before you cover it.

Does the vent go outside or just dump into the attic?
 
   / Insulation above bathroom vent #4  
I have made a box out of 2" Dow Score board over them. I used an ahesive for foam insulation to hold it in place.

If it comes in contact with the fan make sure it is rated for "Insulation Contact".
 
   / Insulation above bathroom vent #5  
Make sure you exhaust fans vents out properly or you will have MAJOR problems in your attic. I strongly agree with take your info from This Old House.
Craig Clayton
 
   / Insulation above bathroom vent
  • Thread Starter
#6  
Thanks.. it is a light/fan combo and is vented to the outside - Ill see if I can dig up the owners manual and see if it is rated for insulation contact

brian
 
   / Insulation above bathroom vent #7  
Another question, was the fan intentionally not covered with insulation, or is it leaking and blowing the insulation away from itself? (Assuming loose cellulose or fiberglass, not bats). As others have mentioned, if it is IC, bury it, otherwise build a box around it and bury that instead.

-rus-
 
   / Insulation above bathroom vent #8  
Last summer I noted our roof sheathing i.e. plywood was turning up at the edges creating humps that were lifting the shingles. Found out that the vent stack pipe had an opening that was allowing moisture from the home to enter the attic space.

Had to replace three sheets of plywood and the shingles...... after replacing the vent stack.
 
   / Insulation above bathroom vent #10  
If the unit is a Nutone Broan 744 - which is the typical builder grade unit for this application(at least for the houses I work in). Then it is approved for contact with insulation. But a foam box as mentioned earlier adds insulation as well as prevents air leaks. A foam box sealed to the drywall with loose fill insulation on top would be your best DIY combination.

If you build a foam box make sure you use a glue or caulk that will not "eat" the foam like most generic construction adhesive will.
 
 
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