Originally Posted By: roconnor
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Mark … Although there is no “standard”, I think your initial gut reaction of 1/4" crack limit is a good rule of thumb (actually an engineer will generally look at anything 1/32" or larger per ACI). You also need to consider paterns and other clues as Gerry pointed out. Non-structural veneer cracks are a judgement call, but it’s indicating problem movement. Also, veneers actually work together with the framed walls sometimes, and you don’t realize it. Here’s some basics from http://www.inspect-ny.com/structure/foundation.htm
Minor, single, isolated, cosmetic, marketing concerns:
1. Cracks, hairline to 1/16" horizontal
2. Cracks, hairline to 1/8" vertical and step; [1/4" ? per Alk - note that this is an unsubstantiated opinion]]
3. Cracks in slabs, hairline to 1/8", not extending into foundation
Modest, monitoring appropriate
1. Horizontal bulge < 1.5", no signs of other significant damage
2. 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.
4. If the cracks are old, with no sign of continuing/recurrent movement - the inspector is more likely to accept monitoring rather than requiring repair.
5. 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 assessment needed. Repair may be needed.
1. >1.5" horizontal bulge/lean or lateral dislocation >1/4".
2. Signs of active, recent, recurrent movement (may be seasonal or ongoing)
3. 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.
4. Signs of repeated repairs to foundation or interior
5. Cracks 1/4" [ 3/8" per Alk] & larger
6. Investigate any finding of which the inspector is uncertain or inexperienced.
WARNING: Don't make conclusions just based on crack size and location. The inspector must consider other site factors conditions, history, materials, external forces, etc. Sudden catastrophes CAN occur, especially where site drainage or other conditions risk undermining or sudden forces on the foundation. (Source: www.ny-inspect.com
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong