frost on subfloor and header

[mmarra]

I have a new house that was built last year. I live in Syracuse where it can get really cold. In 2 corners of the house I have condensation forming on the inside of the wall. I have a poured foundation but have put no insulation in yet because of some issues with the foundation that have yet to be resolved. I did put insulation in the rim joist around the house. As I was inspecting the condensation I took a peek at the corner where te headers meet by removing the insulation of the rim joist. I noticed I have a lot of frost on the floor joist, the header and the subflooring. Last week I put some insulation under the vinal siding hoping to take away any cold air coming in. The builder also put some foam insulation in those areas but it didnt work. Is the normal and should I concered about rotting and mold? I know the builder will tell me its not a concern but he always hasnt giving me the best advice so far. Thanks for any help you can give me!
Mike

[Mark]

For mold to grow you need food, moisture and the right temperature. You appear to have the moisture and food for mold to grow. Right now the temps seem to be to cold but if you continue to get condensation build up or moisture contact with the wood you will have a problem. You may need more caulking, flashing or even a dehumidifierto help reduce air leaks and moisture from entering the basement. The summer months may be worse if moist humid air continues to enter the basement.