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How to Find a Basement Leak in a Finished Basement

Apr 13, 2014 • By Matthew Stock.

Finished Basement Water Problems: What to Do First

To some homeowners, their basement is one big workshop – a place to build things, fix things and, well, putter.

To others, it’s a storage spot, the place for the lawn furniture in the winter, the ski gear in the summer and the place year-round where cardboard boxes go to die.

To still others, perhaps those with large families or overly decorated living rooms or a burning desire for a “man cave,” the basement becomes living space – an extra bedroom, perhaps, or a pleasant hang-out with a comfortable couch, big screen TV and mini-fridge.

But sometimes the paradise that is the finished basement is tarnished.  There’s a trickle of water around the wet bar, a wet spot in the carpeting or a telltale water stain on the drywall. 

Any leak in the basement has very little upside, of course, but at least when the leak is in an unfinished basement, it’s usually fairly easy to detect.  Cracks in walls and floors can be seen, cove seepage is apparent and damp walls are clearly visible.

In the finished basement, however, there’s drywall or paneling (or both) on the walls and carpet or maybe resilient flooring on the floor.   Basement leaks are occurring behind or under one of these surfaces and the spot where the water becomes visible may be far from the place it is entering the basement.

So how does a homeowner find a leak in a finished basement?

Finding a Basement Leak in a Finished Basement

The most common source of water in a poured concrete basement is a non-structural wall crack so the first thing a homeowner should do is look for a crack.

Taking note of where the water was first spotted, inspect that part of the home’s foundation that is visible above ground on the outside of the home.  (If the top of the foundation is buried, dig the soil away so it can be seen and consider seriously rethinking the landscaping.) If the foundation is cracked, the cracks should be visible from the outside; they will be generally vertical and narrow, less than 1/8 “.

Chances are if there’s one crack, there’s another so the inspection should be thorough and not stop when one crack is discovered.

Make sure not to be fooled by form lines, which are vertical lines molded into the concrete from the original wood forms that were used when the foundation was poured.  They are superficial and don’t indicate a crack.

If the cracks aren’t obvious to a homeowner’s visual inspection, it’s time to call in a basement waterproofing contractor.  The pro will know the other common sources of water in similar homes and will likely conduct a “hose test” to determine the exact source of the water.

If a crack is the source of water in the finished basement, there’s no need to tear down the drywall to fix it.  Effective, permanent repairs can be done on the exterior using sodium bentonite clay and they can be done quickly with minimal disruption.

Other exterior waterproofing techniques are also effective against many other sources of water and repairs such as exterior waterproofing membranes and exterior drain tile can solve water problems without damaging the finished basement.

All of this, of course, requires the advice and assistance of professional basement waterproofing contractor to make sure that repairs are done quickly, permanently and cost-effectively.  The basement waterproofing professionals at U.S. Waterproofing have been keeping basements, finished and unfinished, dry all over Chicago, SE Wisconsin and NW Indiana for more than 57 years and they have a list of more than 300,000 satisfied customers to attest to their capabilities.  Why not ask for their free advice?

Tags: basement leak, leak finished basement, finished basement leak

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