We have had a number of experiences in our area that indicate the use of a vapor barrier may not be advisable. The water in a concrete slab placed on a va por barrier has nowhere to go but to the top of the slab. Considerable cracking has resulted, which might not have occurred if no vapor barrier had been used. Aren't we better off without vapor barriers?
Vapor barriers are recommended where floor coverings, household goods or equipment must be protected from damage by moist floor conditions. It is fully recognized that the installation of vapor barriers requires special attention. The trouble from upward movement of water can be minimized by using concrete with a low slump or by using a mix with a short finishing time so that there is less time for the water to move upward. This might be a mix with more cement, Type 111 cement or an accelerator.