We live in WI. Currently humidity is 35% and no water problems that we’ve experienced yet I just discovered these white stuff on some of my floor joists. Our unfinished basement is almost 2,000 sq ft and I’d say maybe 20%, all spread out in different areas, had some amount of this stuff. Is it white mold? Could this possibly be a diy or should I hire out. We had plans to build a bedroom in the basement but now I’m not sure. Any help would be appreciated. TIA