Standard Industry Practices Related To Foundation Movement

The TREC SOP requires licensed inspectors to take into consideration industry standard practices when forming their opinion about how well or poorly a foundation is performing. So, what precisely are these practices and what do they require? The SOP does not tell us specifically what they have in mind.

We are of the opinion that the major reason TREC inspectors have such a hard time providing a performance opinion is the ambiguity in the way “performance” is defined in the SOP. A major source of that ambiguity is the reference to industry standard practices. When it comes to mechanical and electrical systems and components, it is clear which industry standards are applicable. For the most part, all you have to do is make sure the inspected item is functional and that the installation complies with the manufacturer’s requirements.

The following is a discussion of the industry standards we believe inspectors should be familiar with when crafting their foundation performance opinion.

The International One & Two Family Dwelling Code (IRC)

The way the IRC is applied to virtually every required system in the SOP is to first consult the IRC to see what it says. Unfortunately, all the IRC says regarding slab foundations on expansive soils is that they should be designed in compliance with the International Building Code (IBC).

The IBC specifies that conventionally reinforced and post-tensioned slab-on-ground foundations be designed by specific published engineering standards. These are design documents and they do not provide specific information related to foundation performance.

The IBC provides some guidance when it states that the foundation movement due to expansive soils should not cause structural damage to the house and shall not impair the usability and serviceability of the house.

You should note that, in this context, structural damage means damage to a load-carrying element – not to drywall or brick veneer – and usability and serviceability refer to distress such as doors that will not latch, etc.

This is helpful, but not by much.

US Army Corps of Engineers

The US Army Corps of Engineers is regarded by the engineering community as one of the premier engineering organizations in the world. The following is a quote from their publication: Foundations in Expansive Soils.

Most slab foundations that experience some distress are not damaged sufficiently enough to warrant repairs.

There is a lot of wisdom in these few words. Note that it is damage, not distress, elevation measurements, or floor slopes that are used as a foundation repair metric. The focus is on damage to the house due to foundation movement.

Texas Section, America Society Of Civil Engineers

The Texas Section of the American Society of Civil Engineers publishes a document titled: Guidelines for the Evaluation and Repair of Residential Foundations. Here is what you need to know about this guideline:

It is a guideline only. It is not a recommended procedure nor is it a standard of practice document.

The intended audience is the engineering community who make foundation performance evaluations of residential foundations.

The writers were all engineers. Some were also foundation repair contractors. There were no home inspectors or members of the public.

Foundation performance should be assessed on the basis of distress and damage due to foundation movement.

Elevation measurements can be used to estimate overall foundation bending and tilt if a suitable benchmark is available and if there are at least two sets of measurements taken at different times.

If there is no suitable benchmark or only one set of measurements, elevation measurements can be used to gain insight into the distortion mode of the foundation and to make an approximation of the bending and tilt across a profile. The approximation of bending and tilt should be made with an understanding of the applicable construction tolerances.

The document addresses local deflection, but it gives no definition. It does point out that calculating local deflection is problematical because measurements made at locations close to each other are likely to be dominated by as-built conditions.

If the foundation performance is found to be safe, but inadequate, then alternatives should be considered. These would include restoration, adjustment, remediation, or use alternatives. Recommendations made by the engineer should be cost effective, practical, based on projected future performance and the needs of the client.

If a house is found to be unsafe due to foundation movement, foundation repair may be one option among others.

Where no structural safety issue is involved, it is acceptable to make periodic cosmetic repairs and door adjustments rather than other alternatives such as foundation underpinning.

National Foundation Repair Association

This association is the only trade association for foundation repair contractors that we are aware of. The following are based on materials published by this association. The authors are almost all Texas Professional Engineers.

Most foundations fail or underperform, due to lack of proper maintenance, especially poor drainage and tree issues.

Foundation repair cannot make your house like new again.
Foundation repair can make the areas not underpinned less stable.

After any foundation work is done, if the owner does not follow proper maintenance procedures, the repair warranty may be voided and foundation performance may be degraded.

Appraisal Guidelines

You might think that guidelines written for appraisers would not give us much useful insight into what a home inspector needs to know about reporting on foundations. If that describes you, bear with us for a few minutes and hear us out.

FHA Appraisal Guidelines Regarding The Foundation

The following is from the FHA:

The Appraiser must examine the foundation for readily observable evidence of safety or structural deficiencies that may require repair. If a deficiency is noted, the Appraiser must describe the nature of the deficiency and report necessary repairs, alterations, or required inspections in the appraisal where physical deficiencies or adverse conditions are reported.

Notice these terms: “may require repair,” “report necessary repairs, alterations or required inspections.” They are clearly referring to repairs, alterations, and inspections that are required or necessary.

The mortgage company is required by FHA to do the following:

The Mortgagee must confirm that the Structure of the Property will be serviceable for the life of the mortgage. The Mortgagee must confirm that all foundations will be serviceable for the life of the mortgage and adequate to withstand all normal loads imposed.

In practice, the Mortgagee relies on the appraiser to report any conditions that indicate that the house may not meet these criteria.

Fannie Mae Appraisal Guidelines

The appraiser is instructed to look for and identify items in need of immediate repair. If the appraiser sees an adverse condition but does not feel qualified to determine if immediate repair is needed, then the property must be appraised subject to an inspection by a qualified professional.

Freddie Mac Appraisal Guidelines

Freddie Mac has guidelines very similar to Fannie Mae. If any appraiser finds any adverse conditions that affect the habitability, safety or structural integrity of the house, but which the appraiser cannot determine if immediate repair is needed, the house must be appraised subject to inspection by a qualified professional.

A Summary

A foundation performance opinion should be based on the indicators listed in the TREC SOP. The indicators are just that: indicators. They are not dispositive of good or subpar performance. Your performance opinion necessarily is based on your interpretation of what they mean taking into consideration the age and location of the house. 

We recommend you reread this page every few months to remind yourself of what each of the industry standards says.


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