Foundation Crack Repair - All You Need to Know

Posted by Luc Gerber on Sun, Jun 03, 2012 @ 12:19 PM

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Why Foundations Crack

Types of Foundation Cracks

When Foundation Crack Repair is Required

Ignoring Foundation Cracks

Introduction to Foundation Crack Repair

If you are reading this post, it is likely that you either think you need to have a foundation crack repaired in your own home, or you are considering purchasing a property that has one or more cracks and you want to be better informed about foundation cracks. In both cases, you are on the right page so read on...!

In this post we discuss the aspects of foundation crack repair that have the greatest interest to homeowners and prospective home purchasers. Our aim is to provide you with relevant information about foundation cracks in general, the significance of different crack patterns, and to address common homeowner concerns.  

Note: this post pertains exclusively to cracks in poured concrete foundations.

Why Foundations Crack

Foundation cracks in poured concrete foundations are normal and commonplace. Concrete cracks develop for a variety of reasons. Follow these hyperlinks to learn more about why concrete cracks and the available crack repair options and causes of cracks in concrete.

Types of Foundation Cracks

Leaking foundation crack Diagonal foundation crack  Structural foundation crack Settlement foundation cracking
Normal hairline crack Diagonal settlement crack Wide structural crack Foundation failure cracking

The normal hairline crack is the most common type of foundation crack found in most homes. Generally, hairline cracks in concrete are the result of plastic shrinkage of the concrete during the curing process. In this instance, there is evidence of efflorescence and sediment on the foundation wall; the visible staining provides confirmation that the crack has been leaking. This foundation crack would be repaired in order to waterproof the basement.

The diagonal settlement crack is relatively common as well. In this case, the footing has settled and the foundation wall with it. This kind of foundation crack usually occurs because the soil beneath the footing has eroded. In most cases the erosion is caused by the introduction of substantial amounts of water originating from a downspout carrying the rain water from the eavestroughs. By redirecting the downspout further away from the house we can prevent ongoing erosion of the soil beneath the footing and halt crack widening. This particular crack depicted was repaired because it was leaking water into the basement.

The wide structural crack developed due to footing settlement; in this case, the settlement was quite significant. Such settlement generally occurs because the footing supporting the wall was poured on disturbed or insufficiently compacted soil. This crack would be repaired and stabilized with carbon fiber staples. By repairing the crack, crack growth is arrested, basement leaks are prevented, and ants and other insects no longer have easy access into the basement. Foundation cracks 6mm wide or greater are covered for 7 years under Tarion's structural warranty.

The foundation failure cracking is not normally seen. In this example, we can observe abnormal cracking patterns and excessive foundation cracking. This is a picture of a serious situation therefore, if you are contemplating buying a home with similar foundation cracking, you would be wise to avoid this home entirely. For this particular home, the foundation repair solution was the pouring of a second foundation to support the weight of the home.

When Foundation Crack Repair is Mandatory

There are times when foundation crack repair is mandatory unless, of course, you are not concerned about basement leaks or the condition of your foundation. While there are a number of health related reasons to repair foundation cracks causing basement leaks, it is our view that there are 4 situations where foundation crack repair is truly mandatory:

  • When foundation cracks are leaking or have leaked;
  • Prior to selling your home;
  • When you have wide foundation cracks (>3mm);
  • When the cracks are horizontal.

If you have a leaking foundation crack there are several reasons to have it repaired:

  1. A wet or damp basement reduces your living space;
  2. Water that has entered your basement from a leaking foundation crack can ruin personal effects stored in your basement, damage your furnace and rot any framed walls; and
  3. Basement leaks commonly result in mold growth, which can adversely affect your family's health.

There are plenty of sound reasons to repair foundation cracks before listing your home on the market. Click on this hyperlink to read more about why repairing foundation cracks is advisable prior to selling your home.

Although having a relatively wide foundation crack does not mean your house will collapse, there are a few reasons to have them repaired:

  1. A proper crack repair prevents the crack from further widening (wide foundation cracks tend to result in cracks in the brick veneer supported by the foundation);
  2. Basement leaks are prevented; and
  3. Insects are prevented from entering your basement through cracks.

While relatively rare, horizontal cracks in poured concrete foundations are a warning sign. This crack pattern is of concern because horizontal cracks form due to soil pressure on the walls. The pressure on the foundation is so great that the part of the foundation wall beneath the crack is actually being pushed inwards.

Ignoring Foundation Cracks

While it is not mandatory that you repair every single foundation crack in your basement, you may, nonetheless, choose to have them professionally repaired.

Ignoring a leaking crack is always a bad idea because foundation cracks in which water is present is damaging for your foundation. As concrete is porous, it absorbs moisture which, over the long term, causes the concrete to revert to its original "water & sand" state thus weakening your foundation.

Interested in learning more? Check out some of the other pages on this site:

Poured concrete foundation leak repairs

What it costs to repair foundation cracks

Button to contact us for Basement Waterproofing help

Topics: foundation cracks, concrete crack repair, foundation crack repair