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Hydrostatic Pressure

Hydrostatic pressure can have a damaging effect on your basement. The sooner you deal with it, the better.

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While many forces act against your home and its foundation, none is as sneaky as hydrostatic pressure. You will only realize there’s a problem several weeks or months later when moisture becomes a nuisance in your home. 

hydrostatic pressure illustration

What Is Hydrostatic Pressure? 

Hydrostatic pressure refers to the pressure that water exerts on the basement walls and underlying structures. The wetter and deeper the foundation is, the more it is susceptible to damage resulting from hydrostatic pressure. 

Hydrostatic Pressure and Your Basement 

If your basement or foundation walls go down partially or fully beyond the phreatic surface (water table) or are on a sloppy surface where water moves downward, it will experience hydrostatic pressure. This pressure can cause the foundation walls to bow and crack. When this happens, water will start leaking into your basement. 

Water is the main culprit. With a density of almost 1,000 kilograms per cubic meter, water can exert tremendous pressure on obstacles in its way. The resulting pressure is directly proportional to subsurface depth, meaning the pressure increases downwards. The weight of the earth (soil) and water above the surface will determine its impact.  

Signs of Hydrostatic Pressure 

Hydrostatic pressure will always announce itself, though it can take several weeks or months to notice something is wrong. Telltale signs that hydrostatic pressure is building up and attacking your home include: 

  • Water-related problems start during spring and the situation worsens after a runoff 
  • High water soil saturation, resulting in puddles of water forming in some parts of your yard 
  • Water-filled trenches or holes around your home 
  • Strange odors in the basement 
  • Walls bow outward or inward 
  • Cracks in walls and floors 
  • Water seeps into your basement from different directions 
  • Weeping cracks in your walls or concrete slabs 
  • Neighbors with similar houses like yours are also facing the same problems 
  • White, crystalline substances on basement floors and walls 
  • The basement becomes humid 
  • Underground water leaks from your HVAC and plumbing systems 

If you aren’t sure how to do this, just call a qualified contractor. The contractor will check everything, including concrete installations, cracks that are invisible to the human eye, and the extent of the damage your house has suffered.   

How to Control Hydrostatic Pressure 

Once you confirm that hydrostatic pressure is attacking your walls, take immediate action to prevent any further damage to your house. Ask your local foundation repair contractor in Winston-Salem and Raleigh, NC, to come and assess your foundation for damage. If the walls are bowing or have cracks, they’ll fix them before they embark on waterproofing.  

Exterior Waterproofing 

Combining landscaping and a proper exterior drainage system can help arrest your basement leakage problem. Your contractor will figure out how to direct water away from your foundation. They may install an underground drainage system and recommend that you regrade the ground so that it slopes downward and away from the basement. This way, surface water will drain away from the building and not pool around the foundation. 

Also make sure downspouts/gutter extensions extend at least a few feet away from the basement so water won’t pool around your home’s perimeter. 

Interior Waterproofing 

Even with proper grading and drainage, some subsurface water might still cause problems. A good example is underground water that fails to drain away. Such water can cause hydrostatic pressure to build up in your basement floor, leading to cracks. 

To correct this problem, your foundation contractor will install an interior drainage system just underneath your basement floor. The perforated half-pipe will then be covered with gravel before the floor is restored. Once in place, this device will collect any water that enters your basement and direct it to a sump pump system before it causes problems.  

Time is of the essence when dealing with hydrostatic pressure. Contact Tar Heel Basement Systems to schedule a foundation and basement inspection as soon as the signs of hydrostatic pressure become clear. Our experts will come over to investigate what’s going on in your home, and recommend any necessary waterproofing or other repairs to protect your basement from water.

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Winston-Salem, NC 27103


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Fuquay-Varina, NC 27526