Above-Ground Pools and Foundation Problems

Before we start, here’s a quick fact: The average 24’ x 54” above-ground pool holds approximately 15,000 gallons of water.

Ok, let’s stow that little tidbit of information for a second and talk about what causes foundation problems: Soil. Specifically, soil instability.

Why Soil Becomes Unstable

Your home is resting on many different layers of soil. Each layer has different properties, including type and moisture content. How compact or loose each layer is also varies. These layers developed over time, beginning with the Earth’s initial formation. Some soil layers were carried there and deposited by water, wind or glaciers. Today, soil layers are often formed deliberately by companies that develop land for building and home construction. They place layers of fill soil over the soil created or deposited by nature. This is done when they remove soil from hills and put it into valleys to create flat building sites.

Over time soil, whether made by humans or by nature, can become unstable, causing a structure built above it to settle and sink. Drought can cause the soil to shrink and voids to form. Fill soil that was poorly compacted initially can compress over time. And lastly, large amounts of moisture can cause soil to soften (think about stepping into a muddy field).

It’s that last point we’re going to address because it also involves that 15,000 gallons of water we mentioned earlier.

When You Have to Drain Your Above-Ground Pool

First, let’s stipulate that your above-ground pool is designed to have water in it year-round. We’re not talking about an inflatable kiddie pool, after all. But there are times when you will need to drain it, whether to address an issue or simply refresh the water every three-to-five years, as the industry recommends.

You might think you could simply open a valve and let it drain into your yard. But if you do that, the sudden influx of thousands of gallons of water can cause the soil around and under your home to soften, resulting in serious foundation problems. Your home’s foundation can sink, causing the entire structure to become untrue, which can cause issues like sloping floors, sticking doors and windows and gapping ceilings.

Worse, if you have a basement surrounded by clay soils that will expand when wet, they can create pressure on your foundation walls that can cause them to crack, bow or even shear. In the worst case, you might even experience wall failure, necessitating costly and disruptive repairs.

Draining Your Pool the Right Way

If you do have to drain your pool, it’s a good idea to contact a professional to seek their advice. Typically, they’ll have you run a hose from your pool to a sewer, so the water drains straight into the city’s sewage system. Some municipalities will allow you to drain your pool right into the street — but you need to call first to make sure. The main thing is, you really want to direct that water away from your home, so it can’t destabilize the soils that support it.

One other thing, before you drain your pool, consider that you’ll have to refill it when you’re done. That not only takes a long time, but it will also significantly impact your water bill. We’re not just talking about taking a long, hot shower here.

If you are concerned about your home’s foundation — maybe your pool’s been leaking, or you’ve had a recent spate of torrential rain — call Keystone Basement Systems, your local foundation repair company. We've got the expertise and technology to tell you if your home’s foundation is really sitting on solid ground.