Finally have a place to put all three of my girls (all '84 SE's) for the winter in an unheated concrete floor building this year. For my driver(other two are for parts) I put down coardboard AND plastic barrier under it. I noticed recently when visiting there that condensation was building up between the first (cardboard) layer and the second(plastic). Should this be a concern? Should I have only used one or the other? Just wanted some opinions. I also "tee-pee'd" the plastic so any condensation would run away from the peak. Thanks

 

More pics.

 

As long as the water is under the plastic, the plastic is doing its job as a vapor barrier. Not sure if the cardboard is helping much, if you're getting that much water, though.

 

Good question. I have a similar issue. I just finished construction this summer on a 40' x 60' all steal building with 12' sidewalls and is also insulated. It has 6" concrete floors and is unheated. I've noticed that the building can get very humid with weather changes. The steal and floors can get condensation. Just yesterday here in Kansas City, the temp climbed to 60 degrees from a low in the 30’s and it looked like it had rained inside the building. I to have put plastic down under the vehicles but it does not work complexly. No mater what I try, there is no way to stop the condensation.

Would painting the floor with an epoxy concrete paint help with the condensation issue? I really don’t want to heat the building.

 

Painting the floor would help to keep and moisture from seeping through and small cracks or porous areas in the floor, however from the sounds of things its not just coming through the floor.

I've stored my car outside 2 years in a row (if you include this year) I use one tarp underneath and then one on top. So far no problems.

 

You could try ventilating the building; it would get cold, but be dryer.