On Tue, 11 Nov 2008 12:45:23 -0800 (PST), terry
wrote:

On Nov 11, 5:18Â*pm, wrote:
wrote:
the extra moisture coming from the gravel can cause your vehicle to
rust out from below....

Not with a vapor barrier under the stone.

Nick

Level ground, lay heavy plastic damp barrier Maybe couple of layers.
Cover with several inches of gravel. Put in a concrete floor later if
and when it can be afforded.


Only one problem. The cold gravel floor causes condensation when warm
damp air contacts it, the moisture drops through the stone to the
vapour barier, and cannot get away. Earth warms up a bit -
becomeswarmer than the air above, moisture leaves and condenses on the
cold car above. Said cold car has a dusting of salt, and the rust
monster is definitely off and running.

If you are going to have a non-hard-surfaced garage floor you want a
well drained and tiled foundation, with a good coarse granular fill,
covered with a good foot of clean crushed stone, which will drain and
keep things dry, or crushed stone covered with a thick, well tamped
layer of limestone fines. The fines, when compacted damp, become
ALMOST concrete.(and make a good base for a concrete floor in the
future)

If I ever build another garage it will have a re-enforced concrete
floor over about 4 inches(minimum) of high density foam board, and it
will have a central floor drain to catch any melt/runnoff. No more of
this "sloped towards the door" (roughly) that leaves puddles in the
corners.