There is an important distinction to get straight first. A home inspection of the kind you order during a purchase includes a brief visual look at the foundation among two hundred other items. A foundation inspection is a dedicated structural assessment that produces measured elevations. The first tells you someone saw a crack. The second tells you whether the floor is out of level, by how much, and in which direction.
Only the second one is useful when there is money at stake, because only the second one creates a baseline you can measure against later.
1. The walkthrough and the interview
It starts with questions, and the answers matter more than people expect. When did you first notice it? Which doors stick, and in which rooms? Has it got worse, better, or changed with the seasons? Any plumbing work, any trees removed, any grading or landscaping changed?
Seasonality is the single most diagnostic thing you can report. Symptoms that appear in a dry late summer and partially close over winter point squarely at the shrink-swell cycle in expansive clay. Symptoms that only ever get worse point at something else — consolidation, a leak, or a void.
2. Elevation mapping
This is the core of it. A rotating laser or optical level establishes a reference plane, and floor elevations are shot on a grid across the whole footprint — typically every room, plus readings at corners and along load-bearing lines. The output is a topographic map of your floor.
What matters is not absolute level. No house is perfectly level, and plenty of sound houses are out by an inch across their length. What matters is differential movement: how much the floor changes over a given distance, where the low point sits, and whether the shape of the surface is a gentle dish, a sharp local drop, or a tilt along one elevation. Those shapes have different causes and different repairs.
This is also the step that produces the durable artefact. Elevations recorded today are what a survey in three years gets compared against. Without them, a future conversation about whether the house has moved is two people disagreeing.
3. Concrete and structure testing
On slab homes, a rebound hammer gives a non-destructive read on surface hardness that correlates to concrete strength — useful for distinguishing a slab that is sound but unsupported from one that is deteriorating. Cracks get measured for width and, importantly, for vertical offset: a crack whose two sides sit flush is a different problem from one where one side has dropped below the other.
On crawl-space and pier-and-beam homes, the inspection goes underneath. Piers are checked for tipping, cracking and settlement into softened soil; girders and joists for deflection, rot and insect damage; shims for rust and slippage. Moisture readings and relative humidity matter here as much as the structure does, because in a crawl space the two failure modes feed each other.
4. Soil, water and the outside
Then the inspection goes back outdoors, which is where the cause usually lives. Grade direction at the perimeter, downspout discharge points, standing water, gutter condition, uphill stormwater paths, and tree proximity — mature trees draw a startling volume of water out of clay within their root radius.
Where the scope calls for it, soil sampling establishes the composition and depth to competent strata, which is the number that governs pier design and therefore most of the cost. Skipping this step is how projects end up quoted at a depth that turns out to be wrong.
How long it takes, and what it costs
A thorough assessment on an average home runs two to four hours on site. AFW's certification assessment is free and carries no obligation, which is deliberate: the objective is a documented baseline, and a baseline that homeowners avoid because of the price is not doing anyone any good. Independent structural engineers typically charge several hundred dollars for a comparable report, and if you want an opinion with no relationship to anyone who might do the work, that is money well spent.
Be wary of any "free inspection" that arrives without measuring equipment and leaves with a same-day discount offer. An assessment that produces no numbers cannot support a scope, and a price that expires tonight is a sales tactic rather than an engineering finding.
What you should walk away holding
Insist on the documentation regardless of the finding. At minimum: the elevation readings themselves — not a summary, the actual grid — dated photographs of every recorded condition, a written interpretation of what the data indicates, and, if work is recommended, a scope that explains method, count and depth with the reasoning attached.
And if the finding is that nothing needs doing, that is not a wasted morning. A dated survey showing your foundation within tolerance is precisely the document you want the next time a crack appears, or the next time a buyer's inspector raises a question. Read how to tell normal settling from a real problem, see the full certification process, or schedule an inspection.