Condensation in Bathroom ceiling

nlmedic

Hi everyone,

I have a split entry home and I have a master bath on the back of my house. It is a new home that is almost two years old. The bathroom has a two foot stickout the whole width of the bathroom which is 12 feet, so hence there is a stick out in the attic as well. I hope that is clear enough.

I had moisture in the two outside wall/ceiling corners in the bathroom and down the wall a little bit, I called my contractor and he came and looked at it and took the soffit down and looked up in there and there was very little blown in insulation in the attic in that two foot stick out part of the ceiling so there was condensation between the drywall and vapor barrier, he told me to turn the heat up in the bathroom and see if the condensation increased and then we would know for sure what was causing the moisture problem and indeed the condensation increased quite a bit. We did investigate for leaks in the roof and leaks in the HRV lines and in the plumbing vent in the attic and found no problems, it was just isolated to both corners in the ceiling where very little to no inulation was... so I agree that it was a condensation problem due to heat loss into the attic with the heat in the bathroom and taking showers.

I didn't have this problem last winter because that washroom wasn't in use and the heat was off and the door closed and I finished the bathroom this summer and now we are using it and noticed this problem now.

My contractor reinsulated that space but I still have moisture in that area when we turn the heat up and shower in there... with the new insulation in place and no more heat loss there, will this moisture just evaporate and dry up eventually? Or will it be like it for the rest of the winter and then dry up next summer? I know the moisture is trapped between the ceiling drywall and vapor barrier but will it just dry up through evaporation eventually? I hope the condensation is stopped now that it is sufficiently insulated and it just needs to dry.

I live in a northern climate on the east coast of canada.

Sorry for the long winded post but I just wanted to try to explain it clearly.

Dave

mterry

Sounds like you found part of the problem (poor insulation=condensation), but since that is fixed and you still have condensation, I have to wonder also about the ventilation in that bathroom? Is there an exhaust fan? Properly ducted? Properly sized?

nlmedic

The bathroom has it's own fan which goes out to the soffit and then out of a exhaust vent and there is an HRV exhaust there as well.
I don't get any steam on the mirrors or window so I know that the steam/moisture is getting exhausted out.

I'm really hoping that with time the moisture in the drywall will just dry up seeing as I have fixed the heat loss issue.

Dave

joecaption

Where would the moisture have a way to get out?
All I can see is mold forming between the vaper barrier and the sheetrock.

nlmedic

Well that was my concern... how would the moisture get out? I read this on a website that I found about how moisture forms and the different ways it tranfers through building materials "As wall temperatures rise again, or when humidity levels drop, the water re evaporates and is expelled from the wall (framing and sheathing, insulation, or other moisture-absorbed materials) by diffusion or convection."

That is my biggest worry is that I will get mold and then i'm into a big deal and have to pull the ceiling and part of the wall in the bathroom... and it's my master bath that I just finished a few months ago!

Any other ideas or suggestions? I just hope that it will dry up eventually.

tylernt

I thought exhausting at a soffit was against code? The warm air would just rise and enter the attic through the soffit vents, where it would condense and damage wood framing members and insulation.

__________________
The above post is for entertainment purposes only. Its contents may, and probably will, lead to legal liability and damage or loss of property, life, or limb. Use at your own risk.