Signs a foundation is moving
Foundation trouble rarely announces itself all at once. In an Augusta house it usually shows up as a handful of small changes that are easy to dismiss one by one: a bedroom door that started rubbing at the top corner, a window that no longer locks without a shove, a crack angling up from the corner of a doorframe, a gap opening where the baseboard meets the floor. Outside, you might notice a stair-step crack in brick or block, a chimney leaning away from the wall, or a porch slab that has dropped below the threshold.
None of these proves a structural problem by itself. Concrete shrinks as it cures and nearly every slab and block wall has hairline cracks. What separates normal from worrying is pattern and change. Pay attention when:
- a crack is wider at one end than the other, or one side sits higher;
- several doors on the same side of the house begin to stick;
- cracks reappear after being patched;
- floors slope enough that a ball rolls on its own;
- a crack grows over weeks, which you can track with a pencil mark and date at each end.
What the weather does to a foundation
The ground under a house is not static. It swells, shrinks and shifts with the water it holds and the temperatures it goes through, and a foundation rides along with it.
Heat. NOAA's engineering weather data for Augusta/Bush Field gives a 1% summer design temperature of 94°F, with a mean coincident wet-bulb of 76°F. Long hot spells dry the top layers of soil, especially where the sun beats on one side of the house or where large trees pull moisture from the ground. Soil that dries unevenly can let one part of a footing settle more than another.
Rain. The same data lists a 100-year rainfall rate of 4.0 inches per hour. A cloudburst like that can saturate soil along a wall in minutes, particularly where downspouts empty beside the house. Repeated soaking and drying is a common source of uneven movement, and running water can carry soil away from a slab edge.
Freeze and thaw. Bush Field averages about 40 freeze-thaw cycles a year, and its 99% winter design temperature is 25°F. Water that freezes in shallow soil or in a crack expands, and dozens of cycles over a winter can open small cracks a bit at a time, most often in steps, walks and exposed slab edges.
How much any of this matters depends on the soil, the depth of the footings and how the lot drains, none of which can be judged from a weather table. Ask whoever evaluates your house what they think is moving the foundation and why.
Water you can control
Most foundation evaluators start with drainage, because it is the part of the problem a homeowner can change cheaply. Make sure gutters are clear and attached; Bush Field's data lists a 50-year basic wind speed of 90 mph, and a storm that pulls a downspout loose can leave water pouring against one corner for days unnoticed. Extend downspouts well away from the walls, rebuild soil that has settled into a trough along the foundation, and look for water standing beside the house after rain.
Don't overlook the pipes
A leaking water or sewer line under or beside a house can wash out soil just as rain can. Augusta Utilities draws its water from the Savannah River and the Cretaceous Aquifer, but whichever source fills your pipes, a leak in a service line or under a slab puts that water into the ground beneath you. An unexplained rise in the water bill, a meter that turns with every tap closed, or a damp spot in the floor are reasons to have a plumber test the lines before foundation work begins.
An opinion from someone who isn't selling piers
A company that installs piers has a reason to recommend piers. For anything beyond cosmetic cracks, consider paying a structural engineer for a written evaluation. Ask the engineer whether the movement is old or active, what is causing it, and what should be monitored or repaired, in what order.
Repair approaches
Depending on the cause, a fix can be as simple as sealing a crack and correcting drainage. Settled slabs are sometimes lifted with injected foam or grout. Footings that keep sinking may be underpinned with steel piers pushed or screwed down to firmer ground. Bowing walls can be braced or anchored. Ask every contractor why it chose its method, where each pier or anchor goes, and what it expects to happen to the existing cracks.
Before you sign
Ask each company what state license, if any, it holds and look it up on the Georgia Secretary of State's license lookup. Get proof of liability coverage and workers' compensation in writing. Ask which permits the repair needs, who pulls them, and whether an engineer will review the finished work. Get the method, quantities, cleanup, payment schedule and warranty, including whether it transfers to a buyer, on paper.