Concrete Slab Foundation Repair Methods
A Contractor Will Fix Cracks and Sinking on Pier and Beam Homes
Jun 14, 2009
Why do slabs fail? The primary culprit is water, usually not enough, or an unequal distribution. The higher the clay content in the soil, the more susceptible the home is to expensive foundation repair, as well as extensive repair in other parts of the home, including repairs for roof leaks.
These problems can also occur in homes that have pier and beam construction, although the repair in this case are usually much less expensive than on shallow slab-on-grade foundations.
Heed the Warning Signs of Foundation Failure
It's important to spot any sign of failure early and be proactive. Like an abscess that causes a toothache, the longer the patient waits, the worse the pain gets! To add insult to injury, in many situations, homeowners insurance has limited coverage for this type of home damage.
Warning signs include drywall cracks, doors dragging on the finish floor (or more commonly on the door jamb), and windows and kitchen cabinet doors not closing properly. Homes with a brick veneer for siding may show cracks in the mortar joints. The problem may not immediately manifest itself inside the home. Often, problems can be identified by standing out in the street and spotting a dip in the home's roof ridge line.
Repair is not a DIY project. Once a problem is identified it's critical to select a reputable contractor. Be careful; many will try to oversell the job. Always look for an established company offering a transferable warranty.
Foundation Repair by Slabjacking or Mudjacking
Slabjacking is the most appropriate repair method for smaller concrete on-grade slabs such as patios, driveways, and sidewalks. This is a good way to re-level a sunken foundation.
The process involves pumping a concrete slurry mixture under the low spots in the foundation. This added volume lifts the structure to the desired height. As a bonus, it also tends to displace water that accumulates and pools and causes damage, although this is no substitute for vapor or moisture barriers, which many building codes call for in the first place.
The Piling and Piers Method of Foundation Repair
Piers and piles are a better solution for larger re-leveling projects. Rather than just relying on introducing a volume just under the structure, piers or piles work by driving supports much deeper into the soil, deep enough until a stable layer is encountered.
This process is more expensive than slabjacking, simply because it's more involved, more invasive, and involves more labor, mechanical tools, and materials.
Preventing Failures of Slab and Pier and Beam Homes
Since water is the problem, it's no great leap of logic to conclude that moist, evenly-wet soil is the best condition. During dry times, the thirsty soil will visibly draw away from the concrete. It needs to be watered evenly.
One popular solution is to lay soaker hoses around the perimeter and run the water each day as required. How much is enough? The answer depends on a number of variables: soil composition, depth of foundation, and how long it's been since a long drenching rain. Find what works in the area and keep up with it.
As Benjamin Franklin told us, “An ounce of prevention is worth a pound of cure.”
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