Thursday, November 19, 2009

Buyers, San Antonio Home Foundations Require Special Care!

Clay Soil
If you're about to purchase a home in San Antonio, you should know that our local soils are not the best for keeping a foundation from moving.  We have expansive clay soil, which means that the soil expands or contracts as it's moisture content changes.  So during our recent 20 month drought, the soils contracted, or shrank, and then in October - November when we got over 11" of rain, the soils swelled. 

Too Much Rain
The swelling of the soil can cause a foundation to rise, and then fall again when the soil dries out.  The key to keeping the foundation healthy is to keep the moisture content evenly distributed around all sides of the home.  That means, when it rains, the water needs to drain AWAY from the slab, not towards the slab.  You never want to allow water to puddle anywhere around your foundation.  Adding gutters is one way to aid in proper drainage.

Not Enough Rain
It also means that during dry times you need to add moisture to the soil around the perimeter of your home to equalize the moisture that's underneath the slab where it does not dry out as fast. A sign that the soil is too dry is that it will start to pull away from the foundation. Recommendations are for at least 1" per week around all 4 sides of your home, and lots of folks in San Antonio use the soaker hoses to accomplish this if they do not have a sprinkler system. 

San Antonio homes that have concrete foundations are carefully engineered to endure our less than desirable soil, but without proper care, it can cost thousands of dollars to get broken slabs repaired.  Ask your home inspector to show you any areas of concern on the foundation when you are considering a home purchase.

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