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Do Rain and Snow Mean I Have to Seal My Crawl Space in Chicago?

Mar 4, 2013 • By Matthew Stock.

Do Rain and Snow Mean I Have to Seal My Crawl Space in Chicago?


Everybody knows about Chicago winters.  The wind howls, the lake freezes, the snow piles up, kitchen chairs appear in parking spots, right?   Well, not always.  Some winters here are actually fairly mild and snowfall can range from the Blizzard of 2010 – 11 to the almost snow-free winter the very next year.

One thing that is true though, is that winter and early spring here in Chicago are usually wet – from melting snow and ice and/or rainfall.  Most homeowners know that these conditions will cause wet basements in Chicago unless their homes are protected against seepage.  What many don’t realize, though, is that homes with crawl spaces can suffer the same seepage problems and that those problems can be just as damaging to their home and health as water in the basement.

Seal Crawl Spaces in Chicago to Avoid Foundation Damage, Dampness and Mold

Crawl spaces, whether full or partial, can provide badly needed storage for families bursting at the seams, but only if they are properly maintained.  The average crawl space suffers from being “out of sight, out of mind,” especially if it isn’t being used.  However, crawl spaces are just like mini-basements and can be the site of structural foundation damage, excessive dampness and humidity and mold.

Just like basements, seepage in crawl spaces is caused by water in the ground, which can increase in times of heavy rains and snowmelt.  Lateral pressure from over-saturated soil around the walls can cause the walls to crack and allow water to seep in.  Hydrostatic pressure under the foundation can easily cause seepage when the crawl space does not have an impermeable floor and through floor cracks and the cove joint when it does.  Of course, any openings in the wall, such as for windows, pipes and utilities can allow seepage as well.

It may not seem like a big deal when an unused crawl space gets damp from ground water seepage but the presence of water can cause damage to the foundation that may result in a disruptive and costly repair.  Also, water in a crawl space can cause excessive humidity in the living space in the house above and it creates a breeding ground for mold that can damage the home and create serious health problems for its occupants.

So, how can a homeowner seal a crawl space in Chicago?  First of all, with all its similarities to a basement, it should be no surprise that a crawl space can be waterproofed the same way.  If the foundation walls are concrete block, an exterior waterproofing membrane can be applied to create an impermeable barrier to ground water on the “positive side” of the foundation wall.  Interior drain tile and a sump pump can be installed around the inside of the perimeter to carry off ground water and relieve hydrostatic pressure.  Cracks in poured concrete walls can be permanently sealed by injecting them from the interior with expanding polyurethane.

A simple way to seal a crawl space is to replace the dirt floor (usually covered with plastic sheeting or tar paper, with a concrete floor that is poured over a heavy plastic vapor barrier.  This will also provide a dry, stable platform for storage.

One approach unique to crawl spaces, however, is encapsulation.  In this process a heavy, semi-rigid polyethylene layer is laid directly on the dirt or gravel floor.  An insulated liner is then installed on the walls, all the way to the floor joist above and sealed to the floor.  This completely encapsulates the crawl space, leaving it dry, bright and clean and resulting in better air quality in the home and reduced heating and cooling costs.

Regardless of how it’s done, it’s important to the longevity of a home and the health of its occupants that crawl spaces in Chicago be sealed against water intrusion and its harmful effects.  At U.S. Waterproofing, we’ve been sealing crawl spaces (and basements) for Chicago homeowners for decades and we have the experience and expertise to do it the right way at the right price every time.  Why not ask for our free advice before your crawl space becomes a problem?

Tags: crawl space encapsulation, crawl space vapor barrier, crawl space concrete floor, seal crawl space, crawl space chicago

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