Remedy for vapor intrusion on inside slab

[ronh821]

I am involved with a community in Southern California in which some homeowners have experienced problems with apparent excessive vapor intrusion through their slabs, as evidenced by lifting/warping of hardware floors and mildew growth under linoleum. These are five year old homes built on clay fill that drains poorly. This problem has manifested during an extensive drought condition, by the way. There is some evidence that the soil under the slabs was inadequately prepared, e.g., thin drainage layer of sand/gravel and/or only one sheet of visquine with tears/perforations.

My question is: If the problems described above do exist, what are the possible remedies, in order of preference? The primary remedy I have seen proposed to date is a treatment of the inside surface of the slab with a sealant to prevent moisture penetration into the flooring. This solution does not seem to address the fundamental problem, however. Would a drainage system be a better solution and if so, what would be the best type of design?

Thank you in advance for your responses.

 

[Rjeffery]

ronh821,

A treatment of the inside surface of the slab with a sealant to prevent moisture penetration is not appropriate. the vapor pressure will just push any sealer away.

 

[JedClampett]

I have an article from the September 1997 issue of Concrete International regarding this problem. No real solutions except changing the floor to tile or something that is more moisture resistant. It's written by an expert on floor coverings from California named Robert Cox (Robert G. Cox Associates, Pollack Pines). Maybe if you give him a call, he can suggest something.