Cracks in walls, cracks in floors, sloping floors, doors, and windows out of square (see the previous blog for a more detailed description). Now, what do these signify? Do cracks mean foundation repair is necessary?

The questions that most people have in their minds when they see these typical signs of stress are:

• Is this significant? 
• Is this serious? 
• How bad is this? 
• What will happen if left unaddressed?

When people become concerned about these, they often Google them. Because of the tremendous marketing spend of the foundation repair industry, the first and most likely results to pop up are foundation repair contractors. They will, in turn, send out a commissioned salesperson.

Characterization of Signs of Stress

Foundation repair salespeople almost always find a way to characterize all of these cracks as indicative of needing foundation repair—because that is their job. 

They will often come up with a fictitious scale of one to ten and characterize them as in the upper range based on their experience (and the fact that their kids need braces).

But do cracks mean foundation repair in every case? Not necessarily. Signs of stress are broadly characterized by the engineering community into one of three categories:

1. Cosmetic – Minor hairline cracks and similar signs of stress from thermal movement (expanding and shrinking from heating and cooling), dissimilar materials, and other normally occurring processes on building structures.
   
2. Serviceability – This is where the signs of stress are more problematic. They are very unsightly, open and close regularly, allow pests to enter more easily, reduce the effectiveness of the insulation envelope, and would interfere with the selling of a home.
   
3. Structural – This rarer condition is where the stability of the structure is starting to be in question. The load-bearing elements (walls, footings, trusses) that support the roof loads are compromised.

In 30+ years, I have seen very few structurally deficient homes. Most of the problems I encounter are serviceability or cosmetic in nature. Never let a non-engineer imply in any way that the stability of your home is in question.

There are industry-accepted benchmarks that can be used to objectively rate the severity of a home’s foundation movement. Foundation repair contractors do not typically use these—in fact, most don’t even really know about them! 

Forensic engineers, on the other hand, have experience with these benchmarks and can use them to help you understand the severity of the problem in an objective way, with no incentive to sell anything.

Objective Numerical Methods to Determine Severity

I wrote a blog entirely on methods to determine severity.

Often, you will hear contractors and even engineers say something like, “The home is 2” out of level.” This by itself is largely meaningless. The ACI (American Concrete Institute), which is the authority on concrete and foundations, has concluded that most homes are as much as 1.5” out of level to start with.

In addition, it becomes really important to know the horizontal distance over which this difference occurs. For instance, a 2” deviation over 10 feet is much more severe than the same deviation over 50 feet. This concept is referred to as angular distortion or, more recently, tilt.

The FPA later included tilt vs. deflection in its assessments. If the 2” deviation is simply a high point on one side and a low point on the opposite side, the damage would not be as severe as if there were a deflection—in other words, a peak or dip in the slab.

See an example of a typical engineering analysis below.

There has recently been pushback by experienced forensic engineers on this methodology. An improved method has been proposed by Lee and Kalima, which utilizes radius of curvature—in other words, how sharp the change in deflection is. The sharper the change, the more severe the damage.

Again, see this specific blog for more details on these methods. I believe this is an improvement over the FPA/PTI method.

Continuing Movement

As I alluded to earlier, very few of these problems are structural deficiencies. So why not just patch them up and be done with it? Well, you might be able to! The question is: Will the cracks keep coming back? Therein lies the rub.

The cracks in a home that reoccur are almost always a function of soil pressures on the foundation. So then, it boils down to the soil—which is not a simple matter. See my blog here for more details.

Soil is deposited in layers, uneven layers with different mineral contents, densities, affinities, and reactions to water, among many other characteristics. These layers could have multiple things going on under a single house.

The professionals who study the earth and its layering are Geotechnical Engineers, specifically, Forensic Geotechnical Engineers. I discuss this further in this blog. These professionals understand the local geology, its history, and its effects on foundations. They regularly drill and sample the soil to verify its layered content differences in many locations.

These are the only professionals who can answer the question of how the soil is likely to behave in the future and, ultimately, if those soils will continue moving the foundation. If anyone else tries to tell you whether or not your signs of stress will continue, they are BSing you. Not even other engineers, like structural engineers, can credibly opine on this subject.

Possible Options

Once we have a good understanding of the causes of distress and the likelihood of continued movement, an experienced forensic Foundation Repair Engineer can make recommendations and specifications if needed. These are listed below 

• No remedial work needed: It may be that there is very little of consequence going on
• Cosmetic patching: if cosmetic damages need to be repaired from a visual point of view
• Monitoring of the distress to determine the extent of movement over time: This is usually the first line of defense. It’s the best way to help determine future movement. 
• Improving of the consistency of water around the foundation: The easy and cheap solutions that make a big difference
  • Moving water away from the foundation
  • Calculated injection of water to continue to keep the soils in a wet equilibrium
  • Making the perimeter of the house more consistent with the water conditions of the soil.
• Use of an under slab soil drying technology: cheap and easy
• Underpinning: only if it fails in deflection and will continue to move
  • Helical piles
  • Steel push piles
  • Concrete push piles
  • Micro piles
• Pressure Grouting: only if it fails in deflection and continues to move
  • Compaction grouting
  • Intrusion grouting
  • Polyurethane slab jacking
• Cement/Polyurethane slab jacking: good releveling. Don’t fix soil problems
• Concrete slab toping/leveling. Cheap easy releveling. Don’t fix soil problems
• Crack stitching of concrete slabs. Great after other work is done. Or if movement does not continue.
  

You can read more about this in detail in a previous blog.

Key Takeaway

In conclusion, cracks in a home could lead to a variety of solutions. Many are minimally invasive, and contrary to what a foundation repair salesperson will tell you, they do not automatically mean you need to spend $60,000 on underpinning. 

An experienced forensic foundation repair engineer can objectively and fairly determine what is needed for a specific home with signs of distress and help you understand the risks, costs and how you can start with the cheap easy solutions and work your way up if needed.