The color and gauge can also create buckling.Scratches due to walking on them should be touched up to prevent corrosion, salt laden environments will exacerbate corrosion.Improper fastening can create leaks, as well as poor quality/applications of sealants used during installation. 

Excessive wear to painted surfaces outside of what would typically be expected.Faded/mildewed caulking, silicone or other sealants around the bathtub, tiles, sinks, countertops, vanities, etc.Missing caulking around the bathtub and tiles, excessive mildew or water damage, unreported issues potentially.Hard water deposits or stains in sinks, tubs, showers, etc.Buildup of dirt, mold, mildew, or water stains from a preventable or unreported water leak or drip at a fixture or in wet areas or water damage to hard surface flooring resulting from unreported leak or issue.Worn out or deteriorated finishes on deadbolts, locksets, handle sets, loose or stubborn door locks, loose hinges, handles, cabinet pulls, knobs, etc.Broken, lost or unreturned keys, broken door locks, hinges, handles, cabinet pulls, knobs not resulting from normal wear and tear.

This may be good enough for our purposes here, but according to EPA these sealants tend to wear out a few years down the road and radon will creep up again even though the makers and sellers of these products state it's a permanent fix.

They use silicone sealant to seal gaps.

And yes, tell the tenants to run the ventilation fan during a shower, and recaulk using a good thick bead of 100% silicone sealant...but sadly, I think the problem is that the greenboard behind the tile is rotting out.

If the stucco terminates above grade, there is generally a sealant used cover up the foundation from the bottom of the stucco to grade (mostly for aesthetic purposes).

"They covered the poop with some sort of sealant."

If you make prudent use of acoustic sealant and/or hang a second layer of 1/2" drywall over the fire rated - with a liquid acoustic membrane (i.e.

Seal all vent boots and furnace or water heater vents with a clear elastromeric sealant like Through the Roof....we handle several of these repairs a week in Atlanta through HandyANDY and Through the Roof is good for 20 years....great product.When you seal the boots, run a bead of sealant over the tops of the gasket that slides along the vent pipe.  

Cost is about $2400 to mask and spray the whole house with 2 coats.But I've just signed a new 1 year lease with a new tenant so I'm not feeling the ROI is there to have it restored with this clear rejuvenating sealant at this stage.