What Causes Foundation Problems and How to Avoid Them
Grading – Your yard should slope away from your house. The rule of thumb is that the ground should drop at least 6 inches in the first ten feet away from your home. Also, landscaping and concrete (driveways and sidewalks) should not interfere with the ability of water to drain away from the home.
Gutters– You should have gutters installed on your home to control and direct rainwater off the roof and away from your home’s foundation. They should be adequate to handle all the roof runoff. Gutters need to be kept clear of leaves and other debris. They should also be repaired or replaced if they sag or develop leaks.
Downspouts – Downspouts should discharge water at least three feet away from the house. Downspout extensions or buried drains or pipes may be necessary to direct the water away from the home.
Watering your yard and landscaping
Sprinkler system – These should be inspected regularly to ensure that there are no leaks, and that they are not over-watering. (You can place a small bucket or coffee can in your yard to measure how much water different parts of the yard receive.) Sprinkler heads should not spray water directly against the house. They should be adjusted seasonally to avoid over or under watering the yard.
Shrubs and Flowers – Beds close to the house should be checked regularly to ensure that are at the proper moisture level. If you can see a gap between the house and the soil, then this can indicate that the soil is too dry. This gap will also allow a lot of water to fill the gap when it finally rains. This large amount of moisture can cause foundation problems.
Trees – Trees are constantly pulling a lot of water from the soil. Trees must be watered during dry periods. Tree roots can get underneath a home’s foundation and can cause foundation problems. Barriers can be installed to prevent tree roots from growing underneath the foundation.
Foundations and Water
In some areas of the country, including parts of Texas, there is a lot of expansive clay in the soil. Basically, expansive clay acts like a sponge – absorbing water and then drying out. Expansive clay soil gets its name from the fact that it expands significantly as it absorbs water. On the other hand, it also contracts significantly as it dries out. This expansion and contraction can wreak havoc on your home’s foundation as the weather goes through dry periods followed by wet periods. To exacerbate the problem, most homes in Texas are being built with slab-on-grade foundations, and studies and experience have shown that slab-on-grade foundations perform poorly with placed on expansive clay soils.
The expanding and shrinking of the expansive clay soil under your home is what causes the foundation to flex. Expansive clay soils can exert as much as 5500 pounds per square foot of pressure on your home’s foundation. Since the moisture level in the soil changes most significantly around the edges of the home, it is around the edge where most of the pressure will be exerted as the soil goes from dry to wet. Then during a dry spell, as the soil begins to dry out, the soil will contract. This contraction of the soil will then cause the edges of the foundation to sag as they have little support underneath. Over time, this cycling of the soil from dry to wet and from wet to dry, and the resulting flexing of the foundation, can damage your home.
This settling can cause wall cracks, doors to not operate properly, and some unlevelness in the floors. These issues are mostly just cosmetic and annoyances. But, if the movement is significant and is allowed to continue, then this flexing of the concrete can cause some real damage such as cracks in the foundation and broken piping. In order to protect your home, it is essential to protect the foundation and minimize the movement/flexing that it is forced to undergo. The most critical factor in accomplishing this is to minimize the moisture changes in the soil around your home. Foundation watering is the simplest method that has been developed to achieve this. See my post about foundation watering.
Obviously, it is necessary to water more during hot, dry weather and less during cold, damp weather. The amount of water required to keep a foundation stable during the summer can be surprisingly large. One large tree can remove as much as 150 gallons of water from the soil each day. Shrubs and other plants can also remove large quantities of water. During long periods of hot, dry weather, it may be necessary to water a foundation daily.
Watering should supply enough water to keep the moisture content in the soil under the foundation constant. If the amount of water applied is only enough to keep the surface damp, the watering program will not work. You can check the moisture content of you soil by sticking a long blade screwdriver into the ground. If it is difficult to push all the way into the ground, then the soil is too dry. On the other hand, if it comes out of the ground wet, then the soil is too wet. If the screwdriver comes out mostly clean, then the soil level is just about right.
Any water that collects underneath a home’s foundation is a significant problem. It doesn’t matter what the source of the water is (rain, sprinklers, plumbing leaks). Since this water is in an enclosed space, there is very little evaporation that occurs, so the water just accumulates. Water under building foundations accounts for a large majority of foundation failures. Foundation failures resulting from excessive water under a foundation are normally called “upheaval.”
Upheaval refers to the situation that results when the internal (and sometimes external) parts of a home’s foundation rise up higher than their as-built elevation. In expansive soils, this phenomenon almost always occurs due to water accumulation underneath the foundation. Once upheaval occurs, the reinforcement steel in the concrete is permanently deformed or elongated.
As you can see, everything in this post talks about water: rainwater, sprinkler systems, gutters, water under a foundation, etc. Controlling water is essential if you are going to protect your home’s foundation. I hope I have given you some useful information that can help you to take care of your home’s foundation. If you have any questions, please comment below.
© 2020 Mike Morgan
This article was written by Mike Morgan, the owner of Morgan Inspection Services. Morgan Inspection Services has been providing home, septic and well inspection services throughout the central Texas area since 2002. He can be reached at 325-998-4663 or at firstname.lastname@example.org. No article, or portion thereof, may be reproduced or copied without prior written consent of Mike Morgan.