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Structural vs. Non-Structural Foundation Cracks

Seeing cracks in your foundation walls or floor? Cracking can be the result of site conditions, building history, normal curing processes, changes in temperature, foundation settlement, or applied loads, among other issues. While care needs to be taken in diagnosing these cracks, your foundation may not be in such dire straits as you think.

Shrinkage crack off window
Shrinkage crack off window

Non-Structural Cracks

Non-structural cracks in the foundation wall can occur anywhere on a foundation wall, though they often occur where an opening created a variance in the reinforcement in the concrete, such as around the windows, doors, and pipes. Non-structural cracks are the result of lateral pressure from the soil outside the foundation, and will typically leak when the soil is saturated. Types of non-structural cracks can include cracks that appear along form seams, shrinkage cracks, and hairline cracks.


Shrinkage Cracks and Hairline Cracks

Shrinkage cracks and "hairline" cracks (cracks that are less than 1/16" wide) common occurrences in poured foundations. Shrinkage cracks occur naturally in poured concrete during the curing process as the concrete is losing its moisture. On foundation walls, shrinkage cracks are often vertical in nature, may not be one long continuous cracks, and may meander instead of follow a straight line. Shrinkage cracks also appear in poured slab floors. These shrinkage cracks may need to be sealed to keep water from pushing up from below the foundation, as well as to stop radon gas from leaking up into your home. The good news: shrinkage cracks do not signify structural damage and can be easily repaired using Quality Waterproofing’s carbon fiber and epoxy.

Shrinkage crack
Shrinkage crack 

Leaking Form Ties

Leaking form ties are common, non-structural occurrences in poured concrete foundation. Form ties can leak when the hydraulic pressure behind the wall gets to great. A leaking form tie is distinguished by a small, ring-shaped leak, or multiple rings in a vertical line, on the foundation wall, and only requires a carbon fiber and epoxy seal to repair properly.

Leaking form tie
Leaking form tie

Structural Cracks

In poured foundation walls, structural cracks can stem from a poorly-executed backfill, street creep, a settling foundation, hydrostatic pressure from heavy rain, or water under the foundation. Structural cracks often follow similar patterns, such as an “A” shape, or two diagonal cracks intersecting a vertical crack, and can be wider than shrinkage cracks (which can be as wide as 1/8”). Vertical structural cracks are often wider at one end than the other, and denote foundation settlement.

Structural crack
Structural crack

If you believe that the cracks in your foundation are structural in nature, call a professional waterproofing company immediately and have a technician inspect your foundation for leaks and potential foundation issues. For a foundation inspection and a free quote from our estimators, go to our “Get A Free Quote” page and submit a request today.

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