Insulation, Radiant and Vapor Barriers - Moisture on concrete

I have a cabin built on a concrete slab. During the humid summers in MN, I get alot of moisture through the floor. Can anyone recommend a waterproof membrane I can put down to prevent the moisture problem before installing carpeting, or recommend other ideas?

At present the concrete has been painted.

Thanks!

I had the same situation on my cabin on Gull Lake. It was worst on warm days in June and early July. Your situation may be different. Here is what I learned -

Moisture is not coming through the floor. The floor can be cooler than the dew point and water will condense on the floor. You will notice no water under a throw rug if you have it.

I initiall turned the heat down to 40 degrees when gone in the winter and bumped it up when a arrived. This never really kept the floor warm in the later winter. In the worst area, I had 4 sliders facing the lake and just tried to minimize the amount they were opened on the hot, humid days. The other areas where the hot was not pouring over the cold concrete. I had absolutely no problems in the carpeted areas and no water or moisture under the carpet.

Later, because I began to use the cabin every week-end the floor never cooled to that level after that I had condensation. Now in hindsite, since I had a heavily insulated masonry home, I should have left the thermostat at 65 or so all winter, day and night. When I did this, the heat bill for the winter was only about $150 more for the winter and I had consistant conditions and a reasonably warm place to walk into in the winter. Then I bumped it up a few degrees while I was there.

Just my experience.

dick