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The photo above shows a bowed masonry block foundation wall with horizontal cracking that occurred due to earth loading at the time of construction, probably by vehicles driving too close to the foundation wall shortly after it was constructed. At this website we explain how it is sometimes possible to be confident about the cause of foundation damage which in turn helps assess the risk presented to the building.

Photographs of types of foundation cracks and other foundation damage: we have a large library of photographs which we're in process of adding these photographs to this website. Pending completion of that work, contact the author if assistance is required.

FOUNDATION INSPECTION STANDARDS - Foundation Inspection Standards - ASHI Standards of Practice (American Society of Home Inspectors)

The following example of foundation inspection standards is quoted or paraphrased from the ASHI standards. Other home inspection associations such as NAHI, CREIA, CAHI (in Canada), FABI, TAREI, CHI, and their brothers have (or should have) a similar standard for inspecting and reporting on the condition of a building foundation. Those U.S. states or and Canada where home inspectors are licensed also have published their own version (or have based theirs on preexisting versions of) these standards as well. Since the ASHI standards are the oldest and have undergone considerable study and periodic updating, we refer to them here. For the latest version of ASHI's home inspection standards and code of ethics, visit the ASHI website at www.ashi.org.

Notice that in some Standards there was no mention of observations of damage or unsafe conditions!

• This inconsistency in ASHI Standards reflects debate, fear, risk
• Due Diligence: Clients expect inspection to identify concerns & defects
• Engineering and Code Standards: pertain mostly to new construction; engineering analysis of foundation defects and design of repairs is beyond the scope of a professional home inspection and inspector; a home inspector who happens to be qualified to perform such services is not prohibited from doing so on making appropriate arrangements with a client.

But notwithstanding Section 4.1 above, the following section requires the inspector to observe and report evidence of significant damage, including to visible portions of the foundation. Significant in this case means in need of immediate major repair; it might also mean in need of further evaluation by a qualified expert.

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FOUNDATION DAMAGE SEVERITY TERMS - How to Characterize the Severity of Foundation Damage

Based on multiple national ASHI seminar polls conducted by the author - American Society of Home Inspectors (ASHI)

Minor, single, isolated, cosmetic, marketing concerns

• Cracks, hairline to 1/16" horizontal
• Cracks, hairline to 1/8" vertical and step; [1/4" ? per Alk - note that this is an unsubstantiated opinion]]
• Cracks in slabs, hairline to 1/8", not extending into foundation

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Modest foundation damage, monitoring appropriate

• Horizontal bulge < 1.5", no signs of other significant damage
• Leaning wall < 1/3 of wall thickness, from wall base (In author's opinion 1/3 is way too much movement to tolerate; a conventional thickness masonry block wall that leans in one inch over an 8' ht. (or maybe 1.5" per some surveys) might be monitored depending on other site conditions, history, etc. Walls buckled in or leaning more than 1" (or 1.5" in some jurisdictions) should be professionally evaluated further and may require near-term or even immediate repair; Walls buckled in or leaning an inch or less should be monitored.
• If the cracks are old, with no sign of continuing/recurrent movement - the inspector is more likely to accept monitoring rather than requiring repair.
• Cracks described by "wavy mortar" which were caused by damage during backfill while mortar was still "green" or soft (un-cured) and which are not accompanied by other signs of ongoing or additional movement, can be attributed to a single-event and may not require repair (depending on total amount of wall dislocation).

Significant, expert foundation assessment needed. Foundation repair may be needed

• >1.5" horizontal bulge/lean or lateral dislocation >1/4".
• Signs of active, recent, recurrent movement (may be seasonal or ongoing)
• Sudden appearance of cracks, particularly in areas known to have sink-holes (e.g. some areas of the U.S. such as in Florida.) requires immediate assessment.
• Signs of repeated repairs to foundation or interior
• Cracks 1/4" [ 3/8" per Alk] & larger
• Investigate any finding of which the inspector is uncertain or inexperienced.

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• Additional technical contributors & reference sources for this article are listed below.

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FOUNDATION DIAGNOSIS & REPAIR
FOUNDATION INSPECTION METHODS
SITE FACTORS AFFECTING FOUNDATIONS
FOUNDATION CONSTRUCTION TYPES
FAILURES by FOUNDATION TYPE & MATERIAL
FOUNDATION DEFECTS OF OMISSION
FOUNDATION CRACK EVALUATION
  CRACK MONITORING Methods
  DIAGONAL FOUNDATION CRACKS
  HORIZONTAL FOUNDATION CRACKS
  SHRINKAGE vs EXPANSION vs SETTLEMENT
  Sinkholes & Building Damage
  Thermal Expansion Cracking of Brick
  VERTICAL FOUNDATION CRACKSSLAB CRACK EVALUATION
FAILURES by FOUNDATION MOVEMENT TYPE
FOUNDATION BULGE or LEAN MEASUREMENTS
FOUNDATION MOVEMENT ACTIVE vs. STATIC
FOUNDATION DAMAGE SEVERITY
FOUNDATION DAMAGE REPORTS
FOUNDATION REPAIR METHODS
ADDITIONAL READING
FOUNDATION INSPECTION STANDARDS

• "Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
• Sal Alfano - Editor, Journal of Light Construction*
• Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles
• Terry Carson - ASHI
• Mark Cramer - ASHI
• JD Grewell, ASHI
• Duncan Hannay - ASHI, P.E. *
• Bob Klewitz, M.S.C.E., P.E. - ASHI
• Ken Kruger, P.E., AIA - ASHI
• Aaron Kuertz aaronk@appliedtechnologies.com, with Applied Technologies regarding polyurethane foam sealant as other foundation crack repair product - 05/30/2007
• Bob Peterson, Magnum Piering - 800-771-7437 - FL*
• Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
• Greg Robi, Magnum Piering - 800-822-7437 - National*
• Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
• Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
• Dave Wickersheimer, P.E. R.A. - IL*
• *These reviewers have not returned comment 6/95

Technical Edits, Changes, Amendments to This Document

• 08/03/2007 adding text, illustrations, content, organization changes, citations to authority
• 06/07/2007 adding text, illustrations, content
• 5/30/2007 editing to add content on foundation crack repair
• 9/23/2006 editing to clarify text and add content; Technical review (partial) by Arlene Puentes.
• 4/17/2006 editing to clarify text in several sections.
• 2/6/99 editing updates, soliciting additional reviews
• 2/3/99 Converted working text file to MSWord97 .doc and .htm files for easier review on Internet
• 6/26/95 text updates per comments from Al Carson, Terry Carson, Mark Cramer 6/16/95 text updates for Calgary July 1995
• cc's sent to reviewers
• 3/28/95 uploaded to ASHI's Internet site - asfoun01.txt
• 11/19/93 Ed Seaquist - telecon 11/19/93, likes, will write up one of our sections for my/our target of series of journal articles or a book.
• © Dan Friedman 1999, original 1992 All Rights Reserved -- foundation.htm

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