Your home rests on a foundation, which rests on the ground beneath it. That means, your home’s foundation is only as stable as that ground. You might think that “solid” ground is just that — solid. But, the ground beneath your home is actually made up of many different layers of soil, each with its own properties, such as moisture content, density and material type (silt, clay, sand, gravel, etc.). Over time, these layers can shrink and consolidate, causing your home’s foundation to settle and crack. In fact, depending on your home’s exact geographic location, competent load-bearing soil or solid bedrock may be anywhere from a few inches to hundreds of feet below the surface.
There is what’s known as an “active zone” around your home’s foundation that is affected by seasonal changes in moisture. Major weather events such as heavy rains can drastically increase the moisture content of this active zone, causing issues such as increased hydrostatic pressure on your home’s foundation (saturated soil weighs much more than dry soil) and soil softening, which can cause your foundation to settle. Dry periods, too, can create their own problems as soil shrinks, leaving voids into which your foundation can sink.
When a new neighborhood is created, the developers often remove soil from hilltops and place it in valleys, evening out the land to make it suitable for building. This “fill soil,” as it’s known, may not be placed or compacted properly, leaving it prone to settling once it has to bear the full weight of a home and its contents. Of course, these problems arise long after the bulldozers and builders have left and the neighborhood is occupied by families. Sadly, it’s not uncommon for entire developments to be affected by the same foundation issues due to poorly compacted fill soil.
Depending on the age of your home, it is possible that it has already undergone the majority of its settling. But of course, nature is cyclical, which means that wet and dry periods will continue, and the various layers of soil beneath your home will also continue to be affected by these cycles. Really, the only way to be sure that your home is done settling is to find a permanent support solution that doesn’t depend on the unstable soils beneath it.