Strange mold problem in a unit

Never saw this issue before

I have a tenant abandoning a 1980’s double wide unit. Acutally it is a 12 wide with a separately titled add on unit. From the outside it has a lot of appeal. The previous owner installed a new shingle roof, new high quality siding, new skirting and and thermopane windows, covered decks at both the front and back door. It looks nice

Then you walk inside and the funk hits you. Very musty. I expected to see evidence of leaks on the ceiling or under sinks etc but no. In this case the moisture seems to be wicking up from the floor…and pretty much all around the home, not under windows. The home is completely hard surface floors, no carpet

When I mentioned the dampness to the owner, she said that she was aware of it and attributed it to her recent illnesses. She said that during the winter, the home would be so damp inside that water would bead up and run down the inside of the thermopane windows and that she dealt with it by rolling up towels to catch the water before it ran off the sills.

a floor in what should be a dry area…(a back bedroom )seems humped up with the floor nearest the marriage wall dropped.

I’ve worked with several homes with dampness issues by finding the source of the dampness, fixing it and pulling out everything that was mildewed or moldy…but (even tho nice) I am concerned about the liability as well as cost of reno

The skirting looks to be adequately ventilated and the dryer is vented to outside the skirting. The home does not sit in an area with standing water and has both central air and forced air heat.

The client wants to give the home away

How would you go about diagnosing the dampness issue and whether you think this home is a rehab potential or not

given it’s age, I doubt that once rehabbed I could get more than 8000 for the home as loan programs for older homes are hard to come by around here

previously I was offered a 1970’s home without

Have you gone under it and inspected both the soil and the home’s underside? I would turn off the water to the home, crank up the heat for a few days then air it out and see if it goes back to being humid inside. Then turn on the water and test it again in a few days. That should tell you if it is a plumbing problem or not.

Agreed. Wonder what was going on with the home before new siding, roof, floor and windows? I would get into the underbelly first. If a home had major water damage occurring in the subfloor and walls and then you basically covered it up- I wonder how that would play out over time. Would it just eventually dry out??
The whole ‘pretty dress on a pig’ scenario.