If you’ve ever had water issues in your basement and had a professional give you a consultation, more often than not, they mention a thing called hydrostatic pressure. While hydrostatic pressure may be part of the reason you have water in your basement, there is another force called capillary action that could be the culprit. But what is hydrostatic pressure and capillary action, and how does it affect how does it affect waterproofing your basement?
What is Hydrostatic Pressure?
Hydrostatic pressure is the pressure enacted upon a solid surface from the compression of a static liquid due to gravity. In this case, the liquid would be the groundwater pressing against the foundation. The pressure increases as the depth increases. However, pressure doesn’t change even if the amount of water increases. That means even the smallest amount of water can leak through a crack if the pressure is high enough.
How Can You Tell If Hydrostatic Pressure is Causing Water Issues?
The telltale signs of water entering your basement from hydrostatic pressure is that it enters through a crack either on the slab or foundation wall or water coming up from the cove between the wall and slab. If you notice efflorescence (a white powdery-like substance) on your walls with no apparent crack or seam, more likely than not, your foundation is having an issue with capillary action.
What is Capillary Action, and How Does It Affect Your Basement?
The United States Geological Survey defines capillary action as “…The movement of water within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension.”(United States Geological Survey). The best example of capillary action is putting flowers in a vase. When you place a flower in a vase with water, the water barely covers half the stem. The small tubes in the stem wick up the water using capillary action and carry it to the flowers. Concrete is very similar to a stem in this case.
Concrete is a very porous material. Tiny holes dot themselves all across your foundation. Generally, this isn’t much of an issue, but when you have a high water table or standing water underground, the water could start permeating through a solid foundation. All the tiny holes wick up the water like a flower stem and leech the water into your basement. You’ll experience high humidity or dampness in the basement and even signs of efflorescence. Efllorenscence is the limestone leeching out of your foundation wall and leaving a powdery substance behind. If left unchecked, you could experience long-term structural and surface damage on your foundation from the moisture. It’s critical to have a foundation specialist look at your foundation if you notice efflorescence.
What Are the Solutions for Water in Your Basement?
Waterproofing solutions generally fall into two categories: exterior and interior systems.
- Exterior Waterproofing: This proactive approach involves sealing your foundation from the outside. Contractors may excavate the foundation, apply a bitumen seal, or install a membrane system for added protection. A perimeter sump pump system may also be installed.
- Interior Waterproofing: This more affordable, reactive approach manages water after it infiltrates your foundation. Interior perimeter systems guide water to a sump pump, preventing pooling on the floor.
It’s important to research contractors, weigh the pros and cons of each method, and ask about warranties and insurance before making a decision.
