Since the air in the above room is seldom that humid, moisture is going to constantly diffuse from the slab into the air and as the surface dries it will continue to draw moisture up from the bottom of the slab.As in your case when the ground beneath the slab is very wet & the slab surface will remain damp, slick and moisture will condense beneath any objects placed on the slab.

It is very common for homeowners in a neighborhood to not own the minerals beneath their land as developers usually do not transfer the minerals over in the deeds.

But Verizon approached me and ask for lease of the land beneath the tower (about 150 sf) to build a cell (they will take care of landscaping/maintenance)  so they can use the tower (not sure about any deal between Verizon and Oncor).

If the handyman just stuck a shim in the ground, $135 is a lot.  

Soil improvement should be accomplished through grout injection points to compact and improve the density of sandy soils beneath the home.

People with section 8 vouchers feel it's way beneath them because they can go anywhere.

There are also 3 garages beneath the units that could be rented out as well to get additional income.His monthly bills are (mortgage, insurance, water and interest) are $2590,-He is paying for all utilities which i think should be decided amongst the tenants. 

Not sure how since there was a hole in the roof of one of the upper units and a tarp of 4+ months catching rainwater, tenant heating a unit with their gas stove due to lack of heat, foundation about to cave on one side, (Duluth's steep hills could actually collapse the house on cave in) rotting tree trunk holding the house up in the center with 3-4 layers of 2x4 shim board etc etc.  

We took out wood paneling on the walls that had 3 layers of smoke infused wall paper beneath it (really should have just ripped out the drywall...).  

Structures are like people in that the inner condition is reflected in the outer condition, thus any readily apparent deferred maintenance is a harbinger for more problems waiting beneath the surface.