How We Estimate Repair Costs

Every calculator on this site uses the same approach: price each unit the way contractors do, then add the units up.

Where the prices come from

For each item, such as a steel push pier, a linear foot of interior drain tile, or a square foot of 12-mil liner, we collect installed prices from published 2025–2026 sources:

• National cost guides and home services marketplaces
• Price guides published by foundation, waterproofing, and plumbing contractors in different regions
• Manufacturer and supplier pricing for materials such as liners, pumps, and piers

We compare sources and set three values for each item: a low price (simple jobs, low-cost areas, budget materials), a typical price (the middle of what most sources report), and a high price (difficult access, premium materials, long warranties). We drop figures that clearly include different scope or are outliers.

How the calculators work

Each calculator multiplies the quantity you enter by the low, typical, and high unit prices, adds optional items, and then applies a regional adjustment:

• Lower-cost area (rural, small towns): ×0.85
• Average U.S. area: ×1.00
• Higher-cost suburb or city: ×1.15
• Major metro (NYC, Boston, SF Bay, Seattle, DC): ×1.30

Some calculators also adjust for site conditions, such as exterior access for waterproofing, soil type for French drains, depth for sewer lines, and clearance for crawl spaces. The adjustment appears in the calculator.

What estimates include and exclude

Included: labor, materials, and equipment for the listed items, and permits or engineering where you tick them.

Usually excluded: removing and replacing finished walls, flooring, or built-ins; landscaping beyond what is listed; plumbing repairs discovered during the job; and sales tax where it applies to materials.

Limits

These are planning estimates, not quotes. Soil, access, the true extent of damage, local codes, and contractor demand all move real prices. For structural problems, a licensed structural engineer should inspect the house in person. Use our numbers to plan a budget and to check whether quotes are in a reasonable range.

Updates

We review prices at least twice a year. Last update: September 30, 2026. If you have a recent quote that does not match our ranges, we would like to hear about it: hello@basementmath.com.