Evanston, IL is a unique community in many ways.
Home to Northwestern University, it’s a college town but lacks the bars, fast food joints and T-shirt shops that typify many such communities.
It’s a suburb but is most definitely a city, with an old, established downtown area that helps it serve as an urban anchor for Chicago’s North Shore.
It’s been around a long time, getting its start with the founding of Northwestern and the Garrett Theological Seminary in 1851. Evanston was first incorporated in 1863 and became a city in 1892.
The housing stock in Evanston varies widely, from frame bungalows to Victorians, four- and six-flats and townhomes. Evanston also has a large rental community with its 31,000 homes split almost evenly between owner occupants and tenants.
Not surprising, given the city’s history, there are a lot of older homes in Evanston. More than half of the city’s homes were built before World War II and more than three-quarters are at least 50 years old.
Owners of these older homes are facing maintenance and repair issues that develop as houses age. Many have developed foundation problems, including basement seepage, and a large number of Evanston homeowners have discovered basement foundation cracks in their homes.
When an Evanston homeowner finds a basement foundation crack the first thing to be done is to determine if it is structural or non-structural. A structural crack threatens the stability of the foundation and is identified by its width (more than 1/8”) and its typical appearance as part of a pattern. A non-structural crack, on the other hand, is narrower than 1/8”, is a threat only of water seepage and can occur anywhere without pattern.
Both structural and non-structural cracks can originate from the same causes. Oversaturated soil next to the foundation can expand and apply significant pressure against foundation walls, causing cracks and, in extreme cases, inward movement of the wall. Conversely, soil under the foundation can become desiccated during times of drought, causing the soil to compress and the foundation to drop or sink, causing significant cracking and destabilization.
Repairing a non-structural crack to stop or prevent seepage can be done in one of two ways.
The preferred method is to inject the crack from inside the basement with expanding polyurethane. The polyurethane material, contained by an epoxy seal, expands to fill and seal the crack all the way to the outside soil and remains flexible once cured to prevent minor foundation movement from re-opening the crack.
If the crack is inaccessible from the interior, it can be repaired on the outside by creating a waterproof barrier of sodium bentonite clay against the outside of the foundation wall.
The repairs required when structural cracks occur are more complex because they involve re-stabilizing the foundation wall itself and not simply addressing the cracks.
If the structural cracks in a foundation wall indicate that the wall has moved or rotated inward 2” or less, the wall can be repaired and stabilized by applying carbon fiber strips to the wall with industrial-strength epoxy. The carbon fiber can be painted over and covered by a normal stud wall if the basement is to be finished.
If the foundation wall has moved more than 2” low-profile steel channels will be used to stabilize it permanently. The steel is anchored to the foundation footing and tensioned between floor joists above to lock the wall in position and prevent further movement. The steel is sufficiently low profile to be covered by a normal 2 X 4 stud wall.
An Evanston homeowner who discovers basement foundation cracks in his or her home will need the advice and services of a foundation repair expert, basement waterproofing contractor or both. At U.S. Waterproofing, we’ve been sealing non-structural foundation cracks since our founding in 1957 and our team of foundation repair experts make use of engineering data and the latest repair technology to ensure that foundations are permanently stabilized. Why not ask for our free advice?
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