Expansive Clay Soil Contributes to Foundation Heave Problems
In my last few blogs I pointed out how a majority of homes and commercial properties in arid climates get misdiagnosed, and that the majority of soil related damage ends up being heave. Up until now there have been no really viable solutions for that problem….. Until now.
Many years ago I started thinking about how I can solve the seemingly intractable problem of floor slab heave. Over the years I have worked on many ideas with not much success until I returned to the idea of soil venting. Now I am pleased to say that after much long work I have developed a solution that is cost efficient, effective and is non-intrusive.
We developed the MoistureLevel® Smart Foundation System to alleviate expansive soil problems beneath concrete slab foundations. This foundation repair technique borrows from reliable radon mitigation technology, using a vacuum and ventilation pipe to create air movement as well as suction on the under-slab soil. Introducing outside air to the damp, expansive soil causes evaporation to take place, making it possible to reduce soil moisture content and (as a result) damaging soil expansion.
The idea is to use the dry air as it is forced across the soils collecting the moisture and venting it out the stack. As the soil becomes drier, it begins to suck the moisture out of the adjacent clays. As the clays begin to dry out they develop cracks which then dries out the soil near the crack causing it to expand causing it to deepen and make more cracks continuing a self-reinforcing cycle. Over time the clays begin to lose their moisture and cease to expand and in many cases reverse.
The system has protections to minimize any over drying near the footing area. It also has a smart mechanism that monitors the soil moisture content and regulates the drying to protect from over drying.
The system is easy to install usually taking less than a day. The costs are usually less than 1/10th the cost of other less effective measures of heave control and has the following benefits:
- It controls moisture of the clays under the slab in an ongoing basis providing better long term confidence in other repair type solutions
- It controls the indoor air quality for Radon (a radioactive gas) and other gases and pollutants that could be harmful that enter from the ground
- It controls the issues of wet slabs that include delaminating tile, mold and slab curling.
- There is some evidence although unconfirmed at this point that it provides some control for termites since it removes moisture under the slab.
In my next blog I will discuss how I came to think of this and how it compares to current methods of heave remediation of expansive soils.
For more information about expansive soils, click here.
For more information about foundation heave, click here.
