Originally posted 3/26/20, updated 7/21/21.
Simply stated, hydrostatic pressure is important to homeowners because it can damage your foundation. Acculevel has been repairing foundations for more than twenty years, and we know firsthand what happens to a foundation when it’s struggling with water damage.
There is a gap between what homeowners know and need to know about hydrostatic pressure and the issues that it can cause. We’ll walk you through the cause of hydrostatic pressure, what it can do to your home, and when you need to contact a professional.
The Formal Definition of Hydrostatic Pressure
hydrostatic pressure[ hī′drə-stăt′ĭk ]: The pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. Hydrostatic pressure increases in proportion to depth measured from the surface because of the increasing weight of fluid exerting downward force from above.
I don’t know about you, but that definition does not make me feel better informed. In fact, the more I searched for hydrostatic pressure, the more complicated the results became. Search results gave me a wide range of research papers, scientific formulas, even medical journals. (Blood pressure is hydrostatic pressure in your veins!)
So let’s try to break that formal definition down into more everyday terms.
How Hydrostatic Pressure Works
Stay with me, because I’m stating the obvious for a moment. There’s water in the ground around your house. It’s supposed to be there, there’s no way to remove all of it, and it wouldn’t be good for your foundation if it was removed. (Drought can also have a damaging effect on foundations, but that’s a topic for another time.)
Sometimes after heavy rain, or if you live in a high water table, this water collecting around your foundation can be a problem. This is especially true if you live near creeks, ponds, or other bodies of water where soil saturation is naturally high. If enough water accumulates, it starts to “push” or exert pressure against your home’s basement or crawlspace.
Essentially, the water wants to expand into space that your home is occupying and your foundation isn’t allowing it. This is the kind of hydrostatic pressure we’re discussing- it’s much like a dam, blocking water in its path.
Hydrostatic Pressure Can Cause Water Damage
The water pushing against your foundation is applying pressure, but as long as your foundation is secure, your home is stable. The problems occur when the foundation begins to weaken. Foundations are commonly made of some form of concrete, which is a strong substance, but it is also porous.
This means water can seep into and through your walls.
Generally, the first sign a homeowner notices is a musty (damp) smell. If you have a basement, you may see moisture or even water on your basement walls or floor.
Since homeowners rarely enter their crawl spaces, they won’t see the initial signs. The first symptom for them is a stale, moldy odor that indicates mold is actively growing in their crawl space.
Humidity and water leaks are some of the results of hydrostatic pressure. They signal that water has saturated the foundation and found its way into your house. You may need waterproofing or encapsulation to address the water infiltration. You can learn more about these solutions in our detailed guide to basement waterproofing.
But if you have water getting into your home through cracks, you may have larger issues than just water damage.
Hydrostatic Pressure Also Damages Foundations
Some of the foundation issues caused by hydrostatic pressure are more structural. For a detailed review of foundation issues, we have a complete guide here. These issues occur when walls crack from the pressure, and begin to bow inward. You may have water leaking in, but that’s not guaranteed. This bowing is created by pressure, and your foundation’s refusal to yield. The water has gotten into the wall far enough to weaken it and cause cracking.
If you have a wall that is cracking horizontally, or stair-stepping along the blocks, you need to take action promptly (the picture below illustrates both types of crack). If your walls are actually bowing inward, it’s critical to take immediate action.
A bowing wall leads to a breaking or collapsing wall and that is going to be an expensive repair. If a wall collapses, your home may no longer be safe for habitation; living in a hotel is costly and inconvenient.
There are several different methods for repairing a cracked or bowing wall: carbon fiber straps, wall anchors, or helical tiebacks. We explain each of these solutions in this article that reviews each type, how they work, and what they cost.
BEFORE: This picture was taken by an Acculevel project manager during a routine estimate. Multiple cracks, both horizontal and stair-step, are visible.
AFTER: This picture was taken by an Acculevel crew member (same home). The cracks have all been repaired with epoxy, and carbon fiber straps have been installed to strengthen the wall. (FYI: Now that’s it completed, the homeowner can paint over the repair to improve the wall’s appearance.)
Have You Seen Signs of Hydrostatic Pressure in Your House?
If so, you should find an experienced local foundation company, and make an appointment. Most foundation repairs can be done year-round regardless of the weather, so please do not put off these repairs for a different season or warmer temperatures. This is especially true if you have an actively bowing wall. Waiting too long can cause serious structural damage.
Before signing a contract, we recommend that you should verify the company is reputable, insured, and accredited by the Better Business Bureau.
If you live in Indiana or the surrounding states, contact Acculevel. Established in 1996, we specialize in foundation repairs and waterproofing and provide free estimates. An experienced project manager will evaluate your crawl space conditions and recommend the best course of action for you, to keep your home strong and healthy for years to come.