I have stood below my wind turbines during severe rainstorms and did not
detect even the slightest drizzle coming through to the inside.



Thanks everyone for your suggestions.
I have to chuckle about the "too tightly sealed" suggestion. I did my best
but still pretty drafty. Plus, no wind break here so a pretty steady 20 mph
wind.
I've tried the rust preventers, wd-40, and the old standby floor wax.
The poster that mentioned my old attached garage was "slightly" heated may
have been on to something. However, that house had a non-heated foyer
between the house and the garage. Essentially an unheated breezeway. I
also think it's interesting that that attached garage could have standing
water (36-48") puddles in it for days with 100% humidity and I never saw any
rust. We did move about ten miles from that house but pretty much same
weather conditions, no nearby creeks, we're on top of a hill, etc.
One difference is the amount of trees. Our old place was surrounded by
trees, almost completely shaded year round. Our new house has only a couple
of trees and virtually no shade (great for the telescope).
My plan right now (we don't have the money for a new garage) is to cover the
pitched ceiling with foil-backed insulation, seal the floor with that 2-part
epoxy, frame up the interior with 2x4s and add drywall, and add a vent or
two near the ceiling. I'll make it all reusable by screwing it all together
so when we do have the money....
Thanks again,
-Mac