Vertical Foundation Crack - Reported Incorrectly

I am pondering how this formula can be used by a generalist HI during an inspection?
Using this formula, can we make a basic chart of maximum allowable crack(s) gap for a given length of wall?
Such as:
10’ long concrete foundation wall can have a maximum crack gap or cumulative gaps totaling 3/32"
(10 X 12 X 0.00078 = 0.0936inches)
Foundation Length | Maximum Allowable Gap Width

Obviously, there are more considerations that just a gapped crack. Shrinkage cracks tend to be more uniform in width, but do we take the measurement of the widest part. Can we use this formula for angled cracks that are usually more stress-caused (and narrower at one end than the other)?
Can we use this formula as a starting place as we observe foundation cracks?
Other considerations are: What is/are the crack(s) doing? Displacement/offset in any direction? Appear recent or old? Direction of the crack(s). Wall displacement? And things well beyond what we can know or do such as loads, etc.

I would think that one would have to know first if the crack being observed is indeed a shrinkage crack vs. a settlement crack or a crack caused by unreinforced locations like the corner of a basement window or the like. Plus one would have no idea of those design requirements that Randy posted that could all affect the shrinkage.
Just my opinion.

Unless you were involved in a Phase 1 inspection, inspectors or engineers will not have the data to calculate the seven adjustment factors I showed you. So the 0.000780 times the wall or slab length in inches is the best estimate for the total accumulated shrinkage cracks in a foundation wall or slab. Since the concrete wall or slab is “pre broke” at the shrinkage cracks, they are weak links in a chain. Any future settlement or shoving will likely widen or cause offsets in the existing shrinkage cracks. Same goes for any wall openings like windows and doors and vertical offsets in a step down foundation wall. Because of wall imperfections uniform spacing of shrinkage cracks are rare. I rarely see a diagonal shrinkage crack in a wall, except at the corners of basement windows or the top of doors. I would use the 0.000780 factor as just another tool in your tool belt. To me it’s more important to tell your client to monitor shrinkage cracks for movement at least once a year. When I here the phrase " Concrete does two thinks, it gets hard and it cracks" it irritates me like is like fingernails on a chalk board. That statement basically causes homeowners to ignore cracks, but yesterdays shrinkage crack can become tomorrows settlement crack. When the client attends the inspection I always point out typical shrinkage cracks, but I tell them these foundation cracks should be monitored for movement.

To me the 0.000780 factor is more useful on basement floor slabs. Due to offsets in foundation walls stress built-up at reentrant corners can result in one or two large shrinkage cracks. Buyers get worried by a large floor crack, when in fact it’s one large shrinkage cracks versus several smaller ones. I add up the gaps between the floor slab and the foundation walls and the interior floor cracks and compare using the estimated 0.000780. If there is no vertical movement at the cracks, 99% of the time they are just common shrinkage cracks regardless of the crack widths. Like I said in a previous post a 50 foot wall or slab could have just one 1/2" wide shrinkage crack.

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What you said, but I’ll usually add no moisture detected at the time of inspection.

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