How to read a foundation inspection report
Posted September 16, 2026A free inspection is only useful if you can actually understand what it tells you. Here's what the numbers, terms, and recommendations on a real foundation report mean, and how to tell a thorough one from a vague one.
What's actually in a foundation report
A proper inspection produces more than a verbal opinion. At minimum, expect three things: an elevation survey showing relative height measurements across the house, a diagram or floor plan marking where each measurement was taken, and a written recommendation tying a specific repair plan back to those numbers.
Some reports add photos of visible cracking or damage, notes on drainage and soil conditions around the house, and in cases involving a larger job or a disagreement between contractors, a separate structural engineer's report. Not every inspection needs an engineer involved, but the elevation survey and diagram should exist regardless of who performs it.
What the elevation readings actually mean
An elevation survey measures the relative height of the floor at multiple points across the house, compared to a fixed benchmark point, often a spot near an exterior door or a corner that appears stable. Each reading is expressed as inches above or below that benchmark. A reading of negative 1.2 means that spot sits 1.2 inches lower than the benchmark, nothing more on its own.
The metric that actually matters more than any single reading is called angular distortion: the amount of differential movement divided by the distance it occurs over, often written as a ratio like 1 in 300. The reason this matters more than raw inches is scale. One inch of movement concentrated over a 10-foot span is a real problem. The same one inch spread gradually over a 60-foot span is far less significant. As a concrete example, 1.6 inches of movement measured between two points 40 feet apart works out to roughly 1 in 300, which is the point engineering guidance commonly treats as where wall cracking tends to begin, though the exact number varies by structure type and material. A residential report won't always spell this ratio out explicitly even when it's implicitly behind the recommendation.
Worth knowing before you panic
Cosmetic cracking in drywall or brick can show up at less movement than what's generally considered a structural concern. If your report shows movement under typical engineering thresholds but you're still seeing cracks, that's usually not a contradiction, it's a cosmetic symptom of real but modest movement. This is the same distinction our symptom checker draws between "keep an eye on it" and "worth an inspection."
What a pier recommendation should actually explain
The repair recommendation section is where the elevation data turns into an actual plan. A thorough one does three specific things:
Ties the pier count to the readings
The number of piers recommended should correspond to where the survey showed the most movement, not a flat number applied regardless of what the measurements actually found.
Specifies placement
A diagram or description showing where each pier goes, generally concentrated around the areas with the highest differential readings.
Explains the target depth
How deep the piers need to reach to get past the active soil layer to something stable, and why that depth was chosen for your specific lot.
States what "success" means
Whether the plan is to fully re-level the structure or stabilize it at its current position, since bringing an older house back to perfectly level isn't always the right call and can sometimes cause more cracking than it fixes.
If two contractors give you meaningfully different pier counts from what looks like the same set of symptoms, that's exactly the situation where comparing their actual elevation numbers, not just their final quotes, tells you who measured more carefully.
Red flags in a written report
Our guide to vetting a contractor covers red flags in the sales process. This is about the document itself, after the inspection has already happened.
No actual numbers
A report that describes movement in general terms, "noticeable settling observed," without any measurements attached isn't really a survey. It's an opinion presented as one.
No diagram or site plan
You should be able to see where on your house each reading was taken. A report with numbers but no map of where they came from is hard to actually verify.
A pier count with no stated reasoning
If the recommendation doesn't reference the specific readings that led to it, there's no way to check whether the number makes sense for your house.
Language that oversells urgency without data
Real urgency shows up in the numbers, active leaks, rapid recent movement, a documented safety issue. Urgency that relies on alarming language instead of specifics is worth a second look.
Common questions
What do the numbers on an elevation survey mean?
Each number is a relative height measurement, usually in inches, compared to a fixed benchmark point somewhere on the house. A reading of negative 1.2 means that spot sits 1.2 inches lower than the benchmark. On its own, one number does not tell you much; the pattern across the whole house is what matters.
What is angular distortion, and why does it matter more than raw inches?
Angular distortion is differential settlement divided by the distance it occurs over, commonly expressed as a ratio like 1/300. The same 1 inch of movement is a serious problem over a 10-foot span and a minor one over a 60-foot span. Engineering guidance generally treats a ratio around 1/300 as the point where wall cracking commonly begins, though this varies by structure type.
Why does my wall have cracks if my report says movement is within normal limits?
Cosmetic cracking in drywall or masonry can appear at less movement than what's generally considered a structural concern. A report showing movement under commonly cited engineering thresholds does not mean the cracking you're seeing isn't real, it usually means it's a cosmetic symptom of movement that hasn't yet reached the level most engineers would call structurally significant.
What should a pier recommendation actually explain?
It should trace back to the specific elevation readings: how many piers, where they're placed, and why that number was chosen given the measured movement. A recommendation that isn't tied to specific numbers from your own survey is closer to a guess than an engineering-based plan.
What's a red flag in a written inspection report itself?
A report with no actual elevation numbers, no diagram showing where measurements were taken, or vague language like "significant movement observed" without specifics. A thorough report gives you the data, not just a conclusion.
Want a report you can actually read?
Every inspection we arrange includes real elevation readings and a plan that traces back to them, not a verbal estimate. Free, with no obligation.