I notice this from time to time. I’m wondering what causes this and if this is normal occurrence. It’s a covered porch and seems to be coming from behind the siding and close to the walls and corners. I have attached images. It appears to be condensation. Current temperatures are in high 20s.
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Replies
The only case I can think of where this is normal is if the wall is a vented rain screen assembly, and there is very high humidity and rapid temperature changes.
Otherwise, there is moisture collecting behind the siding, and that is not normal.
A leaking roof, wind driven rain forced into the siding, or high humidity inside air leaking through the wall could cause this.
What was the weather like a day or two before you noticed the condensation?
How well sealed is the house?
Type of siding and wall construction / insulation?
What type, and how old is the roof?
This is a new construction, less than 3 years. Exterior walls are 2x6 with R-21. Ceilings are R-38. Temperatures varied throughout the week from low 20s to high 40s. Front entry door faces the South. The sun beats down on front of house. Currently, as of now 12-29-20, it's still the same as original picture, maybe a little less. I included another picture of under the porch. I'm a little stumped on this one. Tyvek house wrap with Mastek 4.5 inch double lap vinyl siding. Vinyl siding looks a little sub standard to me in some places. I was planning on having it redone in near future. Windows have built in j channel which receives vinyl siding. Not impressed with workmanship. We did have snow last week followed by heavy rains and high winds. I think by now these spots should be gone. They are hanging around.
Did you get any icedams on the roof? My front porch gets an ice dam with water getting through the ceiling when conditions are perfect for ice dams (this happens quite infrequently say every couple of years or so.
I regularly check in winter weather or when we get snow, nothing of major concern. My roof trusses are pre fab. I was crawling up in the roof looking around. As mentioned in my original post, I have a covered porch, so there is no partition between roof and covered porch if you know what I mean. On top of the drywall in ceiling is insulation. The porch roof, nothing. So basically if I were to stand on my porch and look up, you see vinyl. No insulation above porch roof, just studs from rafters with no insulation. I'm guessing that might be part of the problem. Vapor, temperature change and air circulation causing condensation. My other guess is moisture coming from concrecte expansion joint to front wall. I don't know at this time. Only assuming. These wet spots seem like it's coming out of the concrete porch in the corners. Strange. So, my only guess is to call a contractor and have them take a look. I'm going to pop out a section of siding close to corner to see what's going on behind there.