Nobody can give you an accurate foundation repair price over the phone, and you should be wary of anyone who tries. What can be explained honestly is how the pricing works, what makes one job cost several times another, and how to read the quotes you are given.
What You Are Actually Paying For
Structural repair is normally priced by the unit of work rather than by the size of your house.
Pier work is priced per pier. The number of piers depends on the length of footing that has to be supported and the spacing the engineering calls for, not on your square footage. A short run along one corner is a very different job from underpinning two full walls, and the price gap between them is large.
Crawl space support is priced by the number of new footings and posts, and is usually a fraction of what perimeter piering costs. This matters because a great many Birmingham houses with sloping floors need exactly this and not underpinning.
Encapsulation is priced largely by square footage, adjusted for how much water management is needed first and whether any framing has to be repaired before the liner goes down.
Drainage is priced by linear foot of trench plus the sump and discharge.
What Pushes the Number Up
Access. A crawl space with eighteen inches of clearance costs more to work in than one with four feet. A steep drive that will not take equipment can force a change of method.
Depth to competent soil. Piers are priced with an allowance for depth, and ground that requires going considerably deeper than expected costs more.
Water. Encapsulating a crawl space that already has standing water means drainage and a sump first. A quote that has not accounted for existing water will change once work starts.
Existing damage. Rotten or termite-damaged framing has to be replaced or sistered before anything is supported on it.
What Should Not Be Assumed
Cosmetic repair is usually excluded. Piers stop the movement; patching drywall, repointing brick, re-hanging doors and replacing cracked tile are typically separate line items or not included at all. Check this explicitly, because it is a common source of surprise.
Full lift is not always achievable or advisable. Recovering every fraction of an inch of settlement can crack finishes that have spent decades adjusting to the current position. Stabilizing and partially lifting is often the better outcome on an older house, and a quote promising complete lift on a 1930s home deserves questioning.
Comparing Quotes Fairly
Ask each contractor for the same three things: the number and type of piers or posts, whether the price is to stabilize or to lift, and what is excluded.
Ask what happens if you do nothing for twelve months. A contractor who can answer that calmly and specifically is diagnosing. One who cannot is selling.
Get a second opinion on anything over a few thousand dollars. Free inspections are standard in this trade and they are sales visits — that is not sinister, but the person assessing your house also sells the repair, and two independent opinions cost you nothing but time.
When the Answer Is To Do Nothing
Some cracking is concrete curing and needs no structural work at all. Some movement is historic, stopped years ago, and stable. Establishing whether movement is active is more useful than measuring how wide a crack is today, and it is the question worth pushing any contractor on.