Using sub slab depressurization to mitigate vapor transmissions

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In my last blog I discussed the vexing problem of vapor transmissions through slabs on grade. In my previous post, MoistureLevel system proves cost effective for treating vapor transmission, I discussed the damage and consequences of moisture vapor as well as moisture transmission through capillary suction in concrete slabs on grade.

I also discussed in more detail the difficulties with current approaches to resolving this problem that are costly, invasive, and present difficulties with performance.

Over the last 13 years David Deatherage PE and I have been developing sub slab depressurization systems. I have filed a patent with the patent trade office approximately 3 years ago and have been installing the systems for almost 2 years with almost 200 of them installed to date.

The advantages to using this system to control vapor transmission through slabs on grade are:

• It is not invasive to install.  Most systems can be installed in one day or less.  No move out required and no moving of furniture or floor coverings.
• It minimizes slab curling since it is drying the slab equally both top and bottom.
• It is effective since it intercepts both vapor and liquid water before it encounters the bottom of the slab.
• It is cost-effective.  Usually in the $1 per square foot range to install with an approximate $4000 and change minimum.
• Longevity.  Since the fan runs continuously, the system controls future moisture problems.  The electricity to run the fan is comparable to a light bulb.

We are now installing this on several projects now for this type of remediation.  Stay tuned for case studies.