What is a Slab on Grade Foundation?
A slab on grade foundation is a common type of home foundation used in areas with expansive soil, like Central Texas. Slab on grade foundations are inexpensive and generally perform well in areas where frost is not an issue.
Why do Engineers choose Slab Foundations?
Slab Foundations are considered to be inexpensive and sturdy. For this reason Engineers around Austin and San Antonio generally prefer to use slab foundations to minimize costs and maximize stability. When designed and poured correctly, slab foundations are reliable.
How are Slab on Grade Foundations Made?
This type of foundation is created from a mold which is formed in the ground where the foundation is to be poured. The mold has a deeper ridge around the edges in order to form a footing. This footing is then reinforced with reinforcing rods. Rebar and post tension cables are then added to the mold per Engineers' instructions. Once the foundation has been prepared, the slab is poured monolithically (all at once). Upon pouring of the concrete, workers ensure that the concrete is evenly distributed by using special tools to keep the foundation level. The post tension cables are tightened as the concrete cures to provide extra support to the slab.
What causes Slab Foundations to Fail?
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Poor Construction
- Sometimes during the design and pouring of a slab foundation mistakes are made, the foundation is improperly prepared, or designed incorrectly.
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Expansive Soils
- Expansive soils in Texas expand or contract more than expected due to extreme weather conditions, oftentimes causing the foundation to fail.
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Improper Drainage
- Drainage around the house allows water to accumulate near the foundation, causing the soil to expand more than normal, thus, increasing pressure on the foundation.
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Plumbing Leaks
- Leaks in pipes add moisture to the soil underneath the foundation causing the soil to expand and weaken the foundation.