How Bad is My Foundation Movement?

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As a homeowner you’re being told that your foundation is moving and needs stabilizing. Your first question is……How bad is my foundation movement? For most homeowners the answer to this question is maddeningly elusive.

If I were asking this question, the first thing I would ask myself is ….what is the motivation of the person giving the answer? If the person answering the question gets a commission for selling me products to fix the foundation movement, then I would be very skeptical about the objectivity of his assessment. I would also want to look at his credentials such as a professional engineer or certification from a national independent foundation repair Association.

The second thing I would ask myself… Is my foundation movement bad….. compared to what? Is there some sort of scale? Or is there a grade? Or pass or fail? I have seen many reports prepared by structural engineers for homeowners. Almost invariably the homeowner is advised that the house is not in any imminent danger of structural collapse. In my 20 years or so in looking at homeowners houses I have almost never seen a house in danger of structural collapse. But really that’s not the right question to be asking. The question to be asking is……. is the home functioning properly? Is it serviceable? The answer to these questions is where the rubber meets the road.

The Texas chapter of the American Society of Civil Engineers (ASCE) and the Foundation Performance Association (FPA) both have adopted standards to judge severity of foundation movement. These are the only agreed-upon consensus standards that I know of. They have two components.

1. Tilt
2. Deflection

Tilt is rather easy to understand. It is simply the slope of the angle from the high side to the low side in a foundation. In other words if it’s 3 inches higher in one place that another and it is 50 feet between them (600 inches) that equals .5% tilt. The standard is 1% Pass or fail mark. If it is over 1% it fails. See the diagram below.

Deflection is the severity of the bend in the foundation. In other words if you have a hump or a dip…. how big is that hump or dip? This is measured with a ratio. The acceptable pass or fail ratio for both ASCE and FPA is L/360. This is the height of the hump or dip (vertical distance) divided by the length that it is measured over (horizontal distance). See the diagram below.

Anything below 1/360 is below the pass/fail mark. Take a look at the handy spreadsheet offered by the FPA for measuring both tilt and deflection.

This is a consensus-based objective analysis that can be used to judge severity of a foundation’s performance. If you are not getting this, then all you are getting is subjective opinions and possibly biased and/or uninformed opinions.

Are you getting a sham investigation?

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You have concerns about your foundation….If you call an inspector to come out, how do you know if you are going to receive something of real practical value…. or not?

I have heard many home owners tell me that an individual has shown up to their home. He looked around for a few minutes gave them some verbal advice and/or sold them some minor repairs and left without giving then anything in writing. Some homeowners when they hire a structural or geotechnical engineer, receive a 1 or 2 page letter. The letter has broad generalizations without a specific repair plan or any objective characterization of severity, but at least it is something.

Is getting some verbal advice really that helpful? Is this scientific? Does it follow any of the guidelines set by any recognized authorities such as the American Society of Civil Engineers or the Foundation Performance Association? Here is the key Question:

Does the inspection include a floor elevation survey?

If it does not it…. Then it is of limited value.  For the following reasons:

1.  Without a floor elevation survey you cannot accurately see where specifically on the            house, the problem starts and stops.

2.  A tilt and deflection analysis cannot be done without a complete (not partial) floor elevation survey.

3.  Severity of the problem cannot be objectively assessed without tilt and deflection analysis. How bad is it? This is the key question that people want to know.

4.  An accurate diagnoses to tell the difference between settlement and heave is almost impossible without looking at contour lines of a floor elevation survey.

If all you are receiving is some verbal advice, then the inspection is not objective, accurate, or helpful…. Especially if it is by a self-proclaimed expert without proper credentials such as a professional engineering license or certification from a foundation repair association.