As anyone involved in the construction field will tell you, subterranean (below ground) construction has a number of problems associated with it. Many of which the layperson wouldn’t expect. Besides the fear of structural collapse and integrity, there comes another creeping issue: water leakage. It’s such a problem in some places that below-ground construction is almost impossible. Florida is infamous for being unable to install basements due to all the work it will take to waterproof them.
Why is Subterranean Water an Issue?
Water becomes an issue as soon as it is decided that construction will include work at or below ground level. It’s especially important because of a process called hydrostatic pressure. Without going into all the complex mathematics and dynamics, it’s essentially the pressure water at equilibrium exerts due to the force of gravity. This also plays into the fact that water, like most liquids, is incompressible. This means that, no matter how hard you press on a determined amount of water, it will not compress into a smaller shape. It will instead disperse out. When homes are being constructed, fluid dispersal isn’t so much out as much as it is up. That is, through the cracks in the concrete and construction. The force of the building being erected above the water table causes the water to flow up through the cracks. Obviously, this causes many significant concerns in a building’s structural integrity.
Waterproofing a basement is a multifaceted approach. There is no one way to go about it and often takes a combination of techniques. The most common and effective way to manage below-ground water is to utilize both draining and prevention techniques. The most common ways that construction agencies go about this is through interior drainage, interior floor and wall sealants, and exterior sealants.
Interior Drainage may seem superficially simple (it’s often just a strategically placed drain), but the reality is much more complicated. For one thing, it isn’t even considered water-proofing. It works to prevent flooding and other water issues but it doesn’t directly prevent water from seeping in. Regardless, it is still considered a method of protecting the subterranean levels of the house. The water flows into the drain and is dispersed into what is called a sump pump. The sump pump consequently flows the water out of the house.
In order to secure poured concrete foundations, a sealant like epoxy or urethane is used to seep in and block any of the inherent cracks. This process isn’t permanent, but is often guaranteed for a decade. It prevents the water from seeping in the points of least resistance and forces it away from the interior. In masonry houses, however, interior sealants aren’t as effective. Interior sealants due prevent high atmospheric humidity for a while which in itself is a common cause of damage. Further methods can include sheets of PVC and other membranes.
Exterior Water Sealing is the only way the IBC (International Building Code) recognizes as adequate water prevention. Asphalt was originally the sealant used to prevent intrusion, but over time the technology has advanced. Just like with the interior sealants, many of the exterior ones are now advanced polymers.