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Hydrostatic Pressure

The soil around your foundation can retain water, resulting in hydrostatic pressure on your foundation walls. This can cause all kinds of damage.

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Before you became a homeowner, you probably didn’t think about all the ways water can affect your home. Water damage is the most common type of damage when it comes to foundations and repairing it can cost a pretty penny. Therefore, it is always best to think about potential problems in advance and take steps to protect your home from them. 

One of the factors that can play a significant role in harming your foundation is hydrostatic pressure. Due to this type of pressure water can enter your basement and wreak havoc all over the place. In case your home sits close to a temporary water table or was built on soil with high water saturation, you will probably have problems with hydrostatic pressure. Let’s explore exactly what hydrostatic pressure is, what causes it, and how to control it. 

high water table

What Is Hydrostatic Pressure? 

Hydrostatic pressure is the force that standing water applies on the surface it comes in contact with. In this case, we are talking about foundation walls. By applying pressure on the walls water can cause structural problems and compromise the health of your home. 

During rainy days and storms, a large amount of water ends up in the ground. It goes into the soil where it slowly builds up. Then, it exerts pressure on the soil around the perimeter of your home, which then pushes the underlying structures such as your home’s foundation. This force should not be underestimated. It is a destructive force and will cause cracks in the walls and make them bow. 

The weight of the water is about 60 pounds per cubic foot. Therefore, at any given moment, thousands of pounds of water could be pushing against your foundation, causing it to crack. Since concrete walls are permeable, the water will find its way into the foundation. Regardless of how solid your foundation is, it cannot withstand such extreme pressure. This is why you need to take the necessary steps to stop water infiltration and preserve the stability of your home. 

What Can Cause Hydrostatic Problems? 

Although soil saturation is the main cause of hydrostatic problems, it is surely not the only one. Soil saturation is the leading cause of water intrusion. However, it’s not the only cause. Troweling the concrete too soon or too much can also pull water to the surface and cause moisture to accumulate on a slab. If there are natural water sources near the house, they can cause hydrostatic pressure and damage the foundation. Also, inexperienced floor installers can cause a lot of problems if they use vapor barriers with low permeability. 

Detecting Hydrostatic Pressure 

If you are interested in whether hydrostatic pressure is threatening to ruin your foundation, there is a simple way to detect this problem. Simply create a small hole in your concrete and see if it will become darker. You can also spread out a plastic sheet and secure it with duct tape and see if water droplets will build up on top of it. 

Another simple way to see if hydrostatic pressure is a potential problem is to measure the moisture level. If it is higher than five percent, your foundation is struggling with hydrostatic issues. You can also use the calcium chloride (CaCl) test to measure the emission rate of moisture, but this test is not recommended for lightweight concrete. Instead, it is much better to use the relative humidity test, which uses a probe to measure the moisture level in the concrete slab. 

Solutions 

Although there are many ways to deal with hydrostatic pressure, the recommended one is to prevent water from infiltrating the concrete. To achieve this, you will need to place a waterproof barrier between the foundation and the water source. With a water barrier, you can help prevent the concrete from absorbing moisture from a high water table or poorly drained backfill. 

Apart from preventing water from infiltrating the concrete, you can also take steps to reduce hydrostatic pressure in poorly draining soils. To do this you will need to invest in a sheet drainage material. It will direct the water toward the foundation drain and reduce pressure on the outside of the wall. In addition, you can use water-based epoxy systems to overcome hydrostatic pressure. 

To keep the water from pooling near your home’s perimeter, you need to make sure that your home is properly graded. If when it rains the rainwater rushes toward your home, you need to regrade your yard. Although this can be a messy project, it will ensure that the water is directed away from your home, which will keep hydrostatic pressure low. 

In addition, you need to maintain your guttering system and make sure there aren’t any clogs. Your downspouts need to channel water away from your home, so it doesn’t soak the earth near your place. Investing in an interior drainage system is also a good idea. Coupled with a sump pump, this system will collect and remove the excess water from the soil before it manages to build up and damage your foundation. 

Hydrostatic pressure can damage your home on so many levels. Therefore, investing in waterproofing measures is money well spent. However, waterproofing the house is a job for professionals, not a DIY project. If you wish to install an interior drainage system or some other solution, contact AFS Foundation & Waterproofing Specialists today to schedule a free inspection. Our experts will assess the situation and recommend waterproofing methods that will completely suit your home and your needs. 

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