Concrete is moist stuff. It begins moist, as a slurry of water and aggregate, and even after it hardens, moisture remains for an incredibly long time. Not only that, basement floor concrete which has hardened is subject to moisture seeping upward. It's vitally important to find out your concrete slab's moisture before some activities, such as installing flooring. The definitive test is with a calcium chloride kit or a relative humidity meter. But here is a simple test that gives you a general idea of the moisture in your concrete.
Difficulty: Easy
Time Required: 2 days
Here's How:
- Cut clear plastic sheeting into a 24" by 24" square.
- Make sure that the concrete where you intend to place the plastic is free of standing water.
- Tape the plastic firmly to the concrete with duct or masking tape. All sides must be secured.
- Wait 48 hours.
- Check the plastic to see if any moisture has beaded up on the inside of the plastic.
Tips:
- This is not a definitive test for moisture in concrete. View is as the "test before the test."
- No beading does not necessarily indicate that there is no moisture, as this is just a simple test. But beading does indicate moisture.
What You Need
- Clear plastic sheeting at least 24" by 24"
- Masking tape
