Elevation survey of the whole floor
Readings are taken room to room and plotted, so the low and high areas are mapped rather than guessed at from the most obvious crack.
Most houses built in and around Fort Worth since the 1960s sit directly on a concrete slab, and when the clay under one edge shrinks away the whole corner follows it down. An independent provider can measure how far and where, then explain what it would take to bring it back.
None of these on their own proves the slab has moved. Together with elevation readings they usually do. The pattern matters as much as the symptom: settlement at one corner looks very different on a survey from a slab that has heaved in the middle after a wet winter, and the two are corrected in opposite directions.

Not every job needs every item below, and a good quote separates what is structural from what is cosmetic. Ask the provider to set out which is which before you decide anything.
Readings are taken room to room and plotted, so the low and high areas are mapped rather than guessed at from the most obvious crack.
Grading, downspouts, flower beds holding water against the wall, irrigation and large trees are all checked, because one of them is usually the reason the soil moved.
Supports go in at measured spacing and the lift is taken gradually, with readings rechecked as it goes, rather than jacking one corner as far as it will go.
Movement can break water and drain lines under the slab, and a leaking line can cause the movement. A test is worth doing when the evidence points that way.
Ask for the number of supports, their positions, the method and exactly what any warranty does and does not cover in writing before work starts.
Some cracks close as the slab comes up and some do not. You should be told which is which, and what will still need patching afterwards.
The realistic choices usually run from doing nothing but fixing the water, through supporting one section of the perimeter, to underpinning most of the exterior. What the survey shows decides which conversation you are actually having, and the cost of a job is driven by how many supports are needed and how hard they are to reach, not by a price per square foot.
If supports are recommended, read how pressed concrete pilings compare with steel piers and how supports are placed and spaced. If the readings show the problem is water rather than structure, drainage correction and root barriers may be the whole answer.
If the cracking itself is what is bothering you, crack repair explains which ones are worth sealing and which are a symptom of movement underneath. Start with a foundation inspection, or see coverage for Mansfield and the rest of the Fort Worth area.
Mostly the number of supports and how hard they are to reach. A low corner needing a handful of supports with clear access is a different job from a house that has dropped along two sides with a patio and mature landscaping in the way. Interior work under the middle of a slab costs more than perimeter work because the floor has to be opened. Ask the provider for the figure in writing after the survey, never over the phone.
Some will, partly. Cracks that opened as the slab dropped often narrow noticeably as it comes back up, but mortar joints, tile and drywall seams that have already broken usually need cosmetic repair afterwards. Anyone promising that every crack will disappear is overselling it. Ask what is expected to close and what you should budget to patch.
Not always, but it is worth considering. An independent structural engineer is paid by you rather than by a repair company, and can write an evaluation and a scope that you then have priced. That is common on larger homes, on properties being bought or sold, and any time you want a second opinion on a recommendation. Ask the provider whether they will work to an engineer scope.
It can, and it is worth ruling out. A supply or drain line leaking under a slab keeps one area of clay wet while the rest dries, which is exactly the recipe for uneven movement. Signs include a warm patch of floor, a water bill that has climbed for no reason, or damp showing at the slab edge. Mention it when you call and ask for the possibility to be checked as part of the visit.
When you call, mention which doors changed and when.