While crawl space foundations have been popular for decades because they offer easy access to the home’s plumbing and electrical wiring, they aren’t without their downsides. One of these is the tendency of crawl spaces to sag over time, for various reasons, including the following:
One of the most common culprits is poor drainage around the foundation. When groundwater can’t drain away from your house as it should, the soil around the foundation can become waterlogged. This can cause the support posts in the crawl space to become non-vertical on the soggy dirt floor.
Drainage issues can also cause trouble when the soil under the foundation contains a lot of clay. This soil type is referred to as “expansive” because it expands when it soaks up moisture and then shrinks when it dries out. This creates movement in the ground and can, over time, also cause crawl space support posts to become non-vertical.
Existing house jacks, if not coated with something to protect them, can deteriorate over time as they’re exposed to moisture. Eventually, they’ll lose their ability to support the floor.
Sometimes, the contractor who built the house didn’t include enough crawl space support piers. This can eventually cause the crawl space to sag. The solution is adding support through support piers or house jacks.
Wooden crawl space support piers are susceptible to wood rot, which will negatively affect structural integrity.