The heavy rainfall of the past few weeks has been a blessing to our drought-ridden desert. However, because of the previously dry monsoon season, the ground has only been able to soak in so much moisture thus, causing water buildup.
Arid climates, like ours, can be very susceptible to flooding because of their hot temperatures and heavy clay soil, according to Bob Brown of Arizona Foundation Solutions, a Rosie-Certified Partner. This can create conditions conducive to foundation heave, which is the uplift of the foundation caused by wet, expanding soil beneath a slab floor. This uplift occurs when it is dry outside of the foundation and wet underneath it. Unusually heavy rainfall can drain off your roof and has nowhere to go other than into the Arizona clay under your home's foundation and slab floor. Moisture may also accumulate under the slab due to plumbing leaks or excessive watering of plants around the foundation. The clay-rich soil expands and swells, and the slab is pushed upward, creating a dome-like heave in the home's foundation.
This movement can lead to stress cracks in the walls and floors of a home. Sections of the slab can be displaced and start tilting, which is known as “heaving.” Most homeowners mistake this occurrence for settling, because to the untrained eye, these processes look similar.
Foundation heave and settlement have very similar symptoms. Here is what to look for:
• Stair-step cracks in brick or concrete block foundation walls
• Leaning, tilting chimneys
• Cracks around doors and windows
• Jamming, sticking doors and windows
• Cracks in a concrete slab floor
• Cracks in drywall
Houses of all ages can heave, though they are more common in older homes, Brown says. The good news is that heaving can be corrected.
To begin with, you need to have a licensed engineer determine whether your house is experiencing "heaving" or "settling." This is done by completing a floor-level reading and plotting those measurements into a 3D topographical map. Once the foundation issue is accurately diagnosed, the repair plan may be composed.
Homeowners need expert help because if someone misdiagnoses this problem as settling, they could recommend that you have underpinning done on your foundation, a process that will cost $30,000 to $40,000. You could do all that only to find out that the problem isn't solved.
Brown and geotechnical engineer, J. D. Deatherage, developed a system that successfully removes moisture from under slabs. The MoistureLevel Smart Foundation System is the first system designed specifically to address foundation heave.
Using a vacuum and piping to create air movement and suction under the slab, an air intake is installed and draws in the dry air required to facilitate evaporation. The moist air under the home is wicked through the pipe and expelled out the roof.
In the process, evaporation removes more than seven pounds of water daily from under the slab. As the soil dries, the foundation heaving process should cease, and it will shrink to its normal, dry dimension. Sometimes, the floor returns to its original level, and sometimes it doesn't; however, data shows a significant improvement at a minimum. The system requires the same amount of electricity to run per hour as a 60-watt light bulb and is equipped with a sensor. Once moisture levels reach the desired point, the system shuts off. If excess moisture is again detected, the system will turn back on to address the issue.
After six months, according to Brown, the damage is significantly reduced, if not eliminated, and the floor can then be repaired, leveled and the cracks filled. The process, not including cosmetic repairs, typically costs $5,000 to $9,000, depending on the square footage of the home.
For more do-it-yourself tips, go to rosieonthehouse.com. An Arizona home building and remodeling industry expert for 35 years, Rosie Romero is the host of the Rosie on the House radio program from 8 to 11 a.m. Saturdays on KTAR-FM (92.3) in Phoenix; KGVY 1080AM 100.7FM; 10 to 11 a.m. on KNST-AM (790) in Tucson.