Unfinished laundry room, frost in stud bays behind insulation
j8687227
| Posted in General Discussion on
Climate zone 5, Northeastern. This is a 2019 new construction build. It’s a split level home.
The plan was to finish the laundry room until discovery of frost build up behind the insulation. We’ve recently had lots of rain about 2 weeks ago, approximately 4 inches in total. We then had a cold front move in followed by 6 inches of snow and then temperatures remained in the single digits to high teens.
We’ve also seen some drywall cracking in the ceiling and wall seems over the last week or two. Basically, it’s been a terrible week.
Yes, I understand that an unfinished room with exposed batt insulation is the culprit of warm moist air hitting the cold substrate of exterior sheathing. Through research and reading online it has been determined that adding drywall and finishing the room will stop the problem.
I’ve decided to open a small hole in the same room, (unfinished laundry room), drywall as shown in photo. I stuck my hand in there and pushed away the batt insulation only to find the same problem, frost behind the insulation. This unfinished laundry room is on the north side and the concrete knee wall shown in photos is below grade. The sun doesn’t hit this side of the house.
Also determined that the rest of the house doesn’t have any vapor barriers. There is no exterior insulation, only Tyvek and vinyl siding.
I’m concerned this frost is in other areas of the house such as the 2nd floor bedrooms and bathrooms.
Would a moisture meter or thermal camera help me determine if this frost problem is occurring in finished areas of the home as well?
I pulled out 2 bays of insulation and it looks like this problem has been going on for quite some time. I’m seeing dark spots near the sheathing and 2 x 6 studs.
Any information, ideas or suggestions would be greatly helpful. How can we determine if this problem is occurring elsewhere in the home? If this a problem due to the room being unfinished we can move forward.
Thank you
Replies
As you mentioned, this is the main reason interior vapor control is called for in your zone.
I cannot see a photo.
Finishing the room likely will help, and do better if you put in a vapor control layer and carefully take care of the details. (seal the edges, take care of floor and ceiling interfaces)
If the kneewall extends partway up the wall, it should also be treated, and the interface beween it and the wall above needs some isolation from each other, and sealing to avoid air leakage.
You can help the rest of the house by checking details and looking for leaks. A thermal imager can help you find leaks from air infiltration (with vents and the dryer going, it will pull cold air in so a good time to check is in winter) You also can use it to look for warm spots on the outside.
You can get inexpensive foam seals to put in outlet covers and switches on outside walls.
Drywall can be part of a vapor control system, but only if properly installed and finished. There are lots of ways to make it leaky.
I managed getting the photos uploaded by changing to JPEG. Yes, not one sheet of vapor barrier to be found. Sad situation which can allow the home to rot inviting every pest that comes along with it.