How to Relieve Hydrostatic Pressure in Your Basement

Hydrostatic pressure is one of the biggest concerns a homeowner should have when it comes to the structural integrity of their home. For instance, cracked walls, bowing walls, and leakage in your basement are all caused by hydrostatic pressure taking its toll on the structure of the property and damaging it in the long run. Therefore, it’s important to deal with hydrostatic pressure and not only the damage it causes.

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What’s Hydrostatic Pressure?

Hydrostatic pressure is a technical term that refers to the pressure that the water puts on the soil around your property. Over time, that pressure tends to build up on the foundation and walls of a home. The walls start to crack and bow, and leakage starts to seep into the basement.

Water can pass through the smallest cracks in the walls even when they appear to be solid and well-built. If you see water leaking in your basement, you’ll want to get to the root of the issue before waterproofing.

The Causes of Hydrostatic Pressure

Soil saturation is the main cause of hydrostatic pressure. However, it’s not the only one. You can experience its force due to other factors too. Here are some of them.

Soil saturation: When it rains or there’s a storm, rainwater has to go somewhere. That somewhere is the soil around and beneath your home. As such, it will build up and push the soil against your foundation walls.
Poor construction: If the builders trowel the concrete too soon or too much, it can also pull water to the surface. While doing so, the moisture will accumulate on the slab and begin to intrude on your lower-grade level.
Natural water sources: Groundwater doesn’t come only from rain, it can be there due to local water sources. Such a natural water source can also cause hydrostatic pressure and damage your foundation.
Poor floor installation: If your construction crew is not very experienced, they may install vapor barriers with low permeability in your home. This will only stave off hydrostatic pressure for a bit and you will be left having to deal with it down the line.

Signs of Hydrostatic Pressure

We should point out that the best way to deal with hydrostatic pressure is through prevention. Luckily, there’s an easy way to determine whether you and your home are in danger of it. You can dig a hole in the ground around your building and see what happens. If the soil becomes darker, it means there’s excessive water in it.

For another test, all you need is a plastic sheet. Simply spread it on your basement floor and secure it with duct tape. If droplets of water appear on it after a while, you can be sure there’s lots of water in your yard, and you should act as soon as possible. Measure the moisture level with professional help. Hydrostatic-pressure-prone soil will have more than 5% of water in it.

Some professionals will suggest that you use calcium chloride (CaCl2) for measuring moisture. Yet, we say that the CaCl2 test works best on lightweight concrete. You should, instead, use the relative humidity test that uses a probe to evaluate moisture levels in your concrete slab. Nevertheless, it’s best to contact professional help before you try doing anything yourself.

Inside and Outside Solutions to Hydrostatic Pressure

Water needs to be drained away so that the pressure can be relieved. It all revolves around removing the water with a drain system. This can be done in two places: the outer wall of the foundation or in your basement or crawl space.

Exterior drainage systems are almost always installed during the construction of a home. Once a home has been built, installing an exterior solution requires extensive excavation and is simply too expensive. We recommend interior drainage systems; let’s take a look at what exterior drainage systems are.

Exterior Drainage System

There are numerous ways to deal with hydrostatic pressure from outside your home. We’ll list out a few that might interest you if you’re looking to solve this problem.

Exterior Drainage Systems: Installing an exterior drainage system can collect water from around the exterior of your property and help it to flow to a central point away from your foundation.
Yard grading: It’s a good idea to ensure you have a positive grade in your yard, which may mean you need to regrade the soil around your home. Sure, it’s a messy process, but it will make sure that water doesn’t pour through the ground and down to your substructure.
Gutters: In addition to any of the previous solutions, you should keep an eye on your gutters. The whole point of gutters is to redirect the water away from your home. But if the downspouts aren’t very effective, they’ll channel water directly into the ground surrounding your foundation. So, check them out too.

In case you’re having trouble with hydrostatic pressure, we suggest that you contact professional help at FSM. Our team in Michigan will be more than happy to give you a free inspection and estimate. Afterward, they’ll present you with a waterproofing solution that will keep your foundation free from water. Remember, hydrostatic pressure isn’t something you’d want to underestimate.

Interior Drainage Solutions

The amount of subsurface water beneath your foundation can vary over time based on the level of rainfall. This can cause a seasonal issue with hydrostatic pressure that will exert weight on the walls and cause cracks.

The interior solution to this is to install a French drain. That’s a foundation drainage system with four major components. These are the drainage pipe, gravel or drainage stone, and the discharge system that consists of a sump basin and sump pump. This installation calls for complex, skilled labor that requires a team of experts with experience in this line of work.

Many basement repair workers from Livonia, MI, install these systems into an already existing home because that area has a large amount of rainfall. However, this is a complicated intervention and it’s best to install such a draining system before the home is built.

Sump Pumps

Sump pumps are an essential part of the drainage system if there’s no slope that can move the water away from the foundation. That means that you’ll need to dig into the basement floors and install a sump pump in the bottom of the hole. The key here is to get a pump that will be strong enough to handle the amount of water accumulating beneath the home. Installing a sump pump isn’t something most homeowners can do on their own. It’s best to let a professional inspect your home and suggest the right sump pump system.

It’s also useful to have at least one backup pump in case something goes wrong. Sump pumps should be able to sustain the increase in water during the rainy season.

Barriers

Once the water is diverted away from the foundation, it’s equally important to install vapor barriers that are permanently fastened to the basement wall. Even the smallest amounts of water won’t be able to enter the insides of the home.

Vapor barriers are 12-mil thick and fastened to the basement walls and used to direct any leakage water to the basement gutter system. It’s something a homeowner needs to keep in mind since the replacement requires digging into the basement. It’s also essential that the team of foundation repair experts that installs your vapor barrier has plenty of experience and that they are able to find the solution suited to the soil on your property and the level of humidity you’re dealing with.

Fixing the Damage

Once the causes of hydrostatic pressure are dealt with, it’s important to fix the damage it’s caused. Sometimes this means sealing the cracks in the walls and sometimes it means installing push piers and bracing the walls so that they slowly return to their original shape and position. For the most part, that can be done by the same team of foundation repair professionals. That’s also a long-term solution after which the home will be safe and usable for at least decades to come.

Hydrostatic pressure causes wall and basement damage and it needs to be resolved since it can bring down the entire home over time. It’s best to start by scheduling a free inspection, that will let you know how difficult the problem is and what needs to be done to fix it.

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Hydrostatic Pressure FAQs

Why does my basement leak when it rains?

Rainwater can increase hydrostatic pressure on basement walls and floors, seeping through existing cracks or imperfections.

What role does soil type play in causing foundation cracks?

Different soil types, such as expansive clay or poorly compacted soil, can exert pressure on foundation walls and contribute to cracks. Understanding your soil’s characteristics helps in devising effective repair strategies.

Why is it important to waterproof my basement?

Waterproofing your basement prevents water damage, mold, and mildew growth, and protects the structural integrity of your home. It also increases living space usability and home value.

Leah Leitow

Content Writer

Leah is a Content Writer for Groundworks with nearly ten years of experience working in the foundation repair industry. Her experience ranges from working with homeowners to find the right solution to training inspectors and staff. In her background as a Michigan journalist, she gained invaluable insight into people's lives throughout our state. Leah lives in metro Detroit with her husband and two sons.