Carl Brahe
Expansive soils can expand 15% in volume from dry to fully saturated. This same soil has the potential to contract to 15% its wet size when dried. In most cases we are concerned with the expansion potential, but in times of drought shrinking soil can cause extensive damage. In extreme cases the soil underneath a foundation shrinks away from the concrete leaving it unsupported causing the foundation to break. Expansive soils cause over a billion dollars a year in damage from expanding or contracting and insurance covers none of the damage.
Before a concrete pad or most types of foundations are poured in expansive soil part of proper preparation is to saturate the soil to a depth of at least a foot and a half. The soil is pre-swollen so when sever dry weather occurs there is the potential for undermining from soil shrinkage.
You can identify dried out expansive soil by the polygon shaped cracks that result. If you see this happening around your home, or building, it is time to take immediate action to prevent damage. If your foundation is undermined by shrinking soil the collapse of the foundation can destroy all above it. Repairing the damage can also be expensive. If you see cracks forming and/or doors and windows stick or don’t open, or your house/building seems to be sinking into the ground, or gaps develop between the earth and foundation, immediate action needs to be taken to prevent further damage. Damage has already been done, but can be minimized if repair is done quickly.
First take action to prevent damage to your foundation and concrete pads. The most immediate action needed is to stabilize the soil by making the moisture content uniform around your foundation. Buy a moisture meter for gardens and house plants at your local hardware store for around $5. Check the moisture levels next to your foundation all the way around the perimeter. Find the highest level of moisture and bring the level of all areas to match it.
The most reliable method of adding moisture uniformly to the soil surrounding your foundation is to install a drip irrigation system. Space drippers evenly about 12” apart around the entire foundation. The drip system will last many years with little maintenance. Water is added slowly and is easy to control.
Soaker hoses can be used for a quick solution. Drip systems last longer but need to be assembled and installed more permanently. Soaker hoses can be laid on the ground and in operation in minutes and are easily moved.
Moisture can be regulated by hand watering, but this is tedious and takes constant diligence to evenly wet the soil. Keep moving, watering one spot for a few moments and moving on to the next if using this method, to avoid uneven watering.
Sprinkler systems can be set up to maintain even moisture around a building. An apron is used with this method to keep water levels uniform around the building. The apron is made of water proof material like plastic that extends 3-5 feet from the foundation. Concrete with a plastic underlay may be used. The plastic is covered with bark, rocks or other landscape materials. Before the apron is installed drainage must be corrected to shed water from near the foundation. This step is often skipped hiding drainage defects that have the potential to cause costly problems. If you are having landscaping done supervise closely to assure that drainage problems are corrected not hidden.
Sprinklers are placed at even intervals 6’ from the foundation. The apron keeps moisture from evaporating and protects the ground from over saturation. Ideally sprinklers are connected to sensors that detect moisture levels and turn on the appropriate sprinklers when water levels drop to a preset level.
Trees and shrubs can suck the moisture out of the ground causing foundation damage if they are planted too close to the building. Trees should be planted at least 10’ from the foundation. Shrubs should be planted at least 3’ away. If you have trees or shrubs closer than this consider removing them, or a moisture shield can be installed extending 8-10’ underground between the tree and the foundation as an alternative.
Much of the country is experiencing a period of drought that ranges from moderate to extreme. Places like much of Colorado that have expansive soil and are experiencing drought are seeing damage from contracting soil. This particular drought across the midland of the US is predicted to last for the foreseeable future. Drought may be temporary or may last for extended periods of time, but when your foundation is threatened quick action must be taken to protect your home or business. The video below shows you how.
How to Spot Foundation Damage Caused by Drought from Allstate
You don’t have to be a weather geek to be well aware of the severe heat waves and drought that have affected much of the country recently. The impact on gardens, once-green lawns and other landscaping is unmistakable.
But what you may not know is that this kind of heat and extended dryness can mean big problems for your home. It can cause the ground beneath your house to harden and crack, and even start moving and sinking.
And of course, when the ground starts to shift it can cause damage to your home’s foundation. Luckily, if you know where to look, these kinds of issues can be spotted and repaired.
