HELP! Water on ceiling vapor barrier (Video)


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Old 01-24-19, 01:03 PM
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HELP! Water on ceiling vapor barrier (Video)

I have uploaded a video to google photos detailing my issue:

https://photos.app.goo.gl/TasrQyNEadJWAgCm7

Could you please take a look and advise? I am getting water pooling between vapor barrier and ceiling in my garage.
 
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Old 01-24-19, 01:31 PM
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You didn't say when the moisture was first noticed. If it got wet when you heated the garage, then that would likely be condensation from warm moist air from the garage hitting cold air in the attic due to the ceiling not being completely air sealed.

Blocking the soffits is not good but is not likely the CAUSE. You should put styrofoam chutes up first, then insulate under that.

It is possible that you have frost in the attic, there is no way to tell without looking. Inadequate venting when combined with heat loss from a heated garage can cause melting on the plywood decking which might cause that drip you noticed. That would seem to be coming from above. Only way to tell for sure it to take it loose and put your head up. Maybe doing that next to the wall will allow you to see into the attic.

If this happened on a warm sunny day it could be frost melting on the underside of the roof sheathing... if the drips are on the sunny side of the roof. You often get a buildup of frost on the shady side of the attic, if you have prolonged cold where the attic never gets above 32F.

Its pretty common for moisture problems to happen like that when there is no good air barrier to seal the poly off. If the whole VB was taped then covered with drywall or OSB that may not have happened.

Heating with propane or kerosene puts a ton of moisture into the air... but are you only using electric heat?
 
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Old 01-24-19, 03:46 PM
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Thank you for your reply. I first noticed this today (which was the first warm, above freezing day we have had in a while) So this lines up very well with your explanation.

I only heat the garage with electric heat.

From your points above, I think I will add a few foam soffit barriers so that there is a little more circulation in the attic, drain the 'puddles', and then complete the vapor barrier job so that its as near air-tight as I can get it.

Once that is done I will continue to monitor for more water.
 
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Old 01-24-19, 03:47 PM
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You would be wise to engineer a "hatch" into your attic space to make it easily accessible. Just be sure it can be air sealed well, with a gasket or something.
 
 

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