Randy:

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**

|10’|3/32”|

|15’|9/64”|

|20’|3/16”|

|25’|15/64”|

|30’|9/32”|

|35’|21/64”|

|40’|3/8”|

|45’|27/64”|

|50’|15/32”|

|55’|33/64”|

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.