5 Ways Homeowners Cause Foundation Problems
Posted by Craig Milam on Mon, Dec 07, 2009 @ 07:53 AM
Overwatering
Overwatering a lawn is a common cause of foundation problems in areas with Vertisols (Expansive Soils).
A frequent source of damage is the differential swelling caused by pockets of moist soil adjacent to dry soil. For example, lawn and garden watering creates a moist zone on the exterior of a foundation, whereas the interior is dry; this creates differential swelling pressure on foundation elements.
source: Damage to Foundation from Expansive Soils (pdf)
Texans tend to overwater due to the unpredictability of the weather patterns. However, maintining a constant moisture level in the soil surrounding your foundation is imperative for home owners. Overwatering exerts added pressure on foundation walls which can cause them to swell upwards, thus causing the infamous, unsightly cracks to appear in walls.
Watering - Year-round watering should be planned to avoid too much moisture in the rainy season and too little in the dry season. Automatic watering systems may help, but they can require a seasonal adjustment and attention to maintenance. If the valve accidentally sticks open, major damage could result.
source: Living with Expansive Soils (pdf)
Installing Landscaping too Close to a Foundation
When considering landscaping for your house, it is important to keep plants a safe distance from the foundation, usually 5 feet or more. Landscaping planted too close to a foundation can cause the soil to expand through overwatering, deprive the plants of moisture (when the roots reach under the foundation), or in cases of trees cause foundation problems because of their roots.
How Close to the House Should You Place Foundation Shrubs?
Having shrubbery right up against your house isn't good for the house, the shrubbery, or for you! So keep the following guidelines in mind when planning a foundation planting:
Locate good-sized shrubs (6 feet tall or higher at maturity) in such a way that their mature foliage will remain at least 5 feet away from the house. You can get away with planting shrubs that stay shorter a bit closer to the house. Where you live also makes some difference. In hot, humid climates, you'll want more air circulating between the house and the foundation shrubs, to discourage rot. Adequate spacing between the plants themselves, too, is important, to reduce disease and maintenance.
source: David Beaulieu - About.com:Landscaping
Improper Installation of Swimming Pools
Swimming pools installed improperly can lead to water seepage into the soil. In Central Texas, the expansive soils will absorb this water and put increased pressure on your home's foundation. Insure that proper waterproofing has been installed when purchasing a home with a swimming pool
As swimming pools are always in direct contact with water and the hydrostatic head is very high, the waterproofing of swimming pools has to be considered very seriously from beginning and adequate steps are to be taken to ensure their water tightness.
source: Swimming Pool Protection System (pdf)
Pool shells always leak some amount of water from natural percolation through the structural gunite skin. If the pool is close enough to adjacent foundations, the entire building can be lifted differentially.
source: Damage to Foundation from Expansive Soils (pdf)
Improper drainage
Proper drainage is an essential part of any home design. Included in this are gutters which deposit the water far enough away from the foundation to prevent it from influencing the foundation. Also a proper grade in which the land around the house gradually slopes downward, away from the house and deposits runoff water on the streets.
The foundation should always be provided with adequate drainage, and the soil properly prepared to minimize changes in soil moisture and differential movement.
source: US Department of Defense: Foundations in Expansive Soils (PDF) section: 7-1
Superior Foundation Repair recommends depositing water from gutters and downspouts 10 feet (or further) from home foundations located in areas with expansive soils. Superior also recommends a grade of 3-5% sloping away from the foundation.
Interior Remodeling
When remodeling your home, it is important to understand why your home was designed the way it was in the first place. A major remodeling project which shifts the load of the house significantly, can adversely affect the original design of a foundation. Removal of supporting walls can wreak havoc. Also installing add-ons to a house situated on expansive soil can have the reverse effect intended, if not properly desinged for expansive soils. Make sure your contractor uses a design which will not be adversely affected by shrinking and swelling.
Interior finishing. One of the most costly mistakes a homeowner or careless contractor can make is to defeat the design purpose of a floating floor slab. A floating garage or basement floor slab is designed to move freely. Therefore, any furring, paneling, dry wall, or interior partitions added to a basement or garage must maintain this freedom of vertical movement. Any added walls or wall coverings should be suspended from the existing walls or ceiling, and should not be attached to the floor slab. A minimum void space of 3 in. should then be provided just above the floor slab. This void space may be covered with flexible molding, or inflexible molding attached to the floor rather than the wall. Although these recommendations provide for 3 in. of upward swell of the soil beneath the floor slab, more void space may be necessary in areas of highly swelling clay. source: Colorado Geological Survey: Mitigation and Land Use (Swelling Soil)
Should your house experience foundation problems due to improper maintenance. Contact Superior Foundation Repair immediately for a Free Foundation Repair Estimate on the extent of damage done to your home.
Read our Foundation Maintenance tips for more information on maintaining a healthy home foundation