Hi,
I have what may or may not be an issue with frost in my attic.
First a little background....
I have a bungalo built in the 50's that has a gable style roof. The home has plasterboard walls with what appears to be kraft paper for a vapor barrier. Original insulation is in the rafters (sawdust) as well as fiberglass bats on top (R12).
2 x 4 construction, as well as 2 x 4 for the rafters. The roof has 10 inch by 30 inch vents on the gables, as well as a few vents about 2 feet from the peak. The peak vents appear to be added at a later date. All vents have screening on them to keep out bugs and critters.I'm currently doing a bathroom reno, gutted to the studs, replaced the sawdust with R12 fiberglass, installed vapor barrier with acoustic sealant around the top plates of the walls.
Three walls are drywalled as well as the roof. The bathroom vent has rigid metal pipe, insulated and sealed with tuck tape. The vent housing was also sealed with tuck tape and gaps around the housing have been sealed with expanding foam.
The lone wall without drywall is the tub alcove. That will be covered with durock, but I had to install the tub before I could do that.
Here is where my problem begins....
I was installing the supply pipes for the tub and I noticed a wet spot between the studs on the open wall. At first, I thought a pipe may be leaking, but on further inspection, I saw a leak working it's way through the acoustic sealant where the vapor barrier was starting to lift.
I thought to myself, holy crap, my roof is leaking.... So I went to where my attic hatch is (not in the bathroom), popped it open and noticed that the underside of the roof had a light layer of frost which was melting and falling onto the insulation.
The weather has warmed up here considerably for January and recently rose from a -25 C high to around 0 C. There was no wind on the day that this happened and the leak has now dried up on it's own. The time frame for all of this was about 5 days.
I checked the attic last night and there is still frost on the underside of the roof, but the melting has stopped, and no new frost has formed.
I suspect that this may be normal for this type of house and I probably wouldn't have a leak if the wall covering was in place, and I don't see any signs of roof leakage anywhere else in the home. I've been in the house for
9 years.I'm thinking I may need to upgrade the venting in the attic. The front of the house has a oversize eave that is stucco'd. This is common on all the houses of my style in this neighborhood. This eave does not have venting and I suspect the gable vents and newer roof aren't doing the job.
Any opinions on how to handle this? Perhaps I'm being paranoid and I should just leave things for now.