Hi all,

I have a 95 yo basement with a decaying floor that wicks moisture into
anything you rest on it. I installed a sump pump which helped, but
didn't solve it. There may be an issue with a high water table or a
natural spring. The cement is aged and cracked, but basically sound.
A few spots heaved up for some reason (Continental drift contributing
to mountain building forces perhaps? g), and the entire floor has a
(coal?) cinder base under it. If I put a piece of plastic down in any
spot for more than a day, it gets quite moist underneath. Since my
workshop is there, the dampness is causing all my tools to rust.

The proper solution here is to hammer up the floor, remove the cinder
base, level the dirt, lay a smooth gravel bed, and have a truck back up
to the vent window while a 4-man crew spreads a new slab. The proper
solution is also a lot more expensive and time consuming than I can
currently manage. I would have to remove the old floor to maintain my
head clearance which is already a little tight, and the basement has no
direct access to my back yard.

The improper solution I came up with is to remove and patch the heaves,
and then use latex fortified thinset with cement fiber backer board
over the whole floor. I would close the seems it with fiber tape and
thinset, and pour a leveling compound over the entire mess. After the
proper curing time, a quick coat of epoxy paint to finish it off.
Instead of a 3" or 4" floor raise, I would be looking at a 1/2"
to 3/4" one. It also seams like this solution would be strong,
watertight, and look attractive.

Any reason why I shouldn't pursue it? IOW, Could someone please talk
me out of this? Also, does anyone have an alternative to the two
approaches mentioned above?

Many thanks in advance.