We have a new home built in 2020 that we moved into in July of 2020. By the end of September I had found mold on the baseboard in the northwest bedroom. The builder identified a defect with the spray foam insulation not being installed in the joist box ends. There was a shower of moisture running down the wall in certain areas all along the concrete wall in the entire basement.
The builder fixed this defect by January 2021. In July of 2021, after an excessively hot summer, I found mold again in the same northwest bedroom and in the rest of the basement in certain spots. It seems there is moisture accumulating behind the drywall that is sealed with vapour barrier paint on the drywall, no poly vapour barrier.
We had to hire and investigate on our own to make the warranty claim. Warranty has not been helpful what so ever and the builder is also not actively involved as they wait for instruction from home warranty. The problem identified by a building science company was with rising damp. The solution presented would be to spray foam the entire basement cement walls. At this stage I have seen very similar posts here and wanted to find out what solution worked and what the outcome was either with home warranty or as the homeowner.
I am actively monitoring the moisture content in the baseboards and can see it rising during the summer. We do live in a semi-dessert location and the problem has been most active during the heat of summer in drought conditions.