How pricing research is performed

Why we do not publish a national average

Mitigation cost is driven by the house, not by the market. A poured-basement ranch with a garage and an accessible slab is a different job from a farmhouse with a partial basement, a crawl space under an addition, and a slab-on-grade extension — and the second is a different job again from a hillside house with three soil-contact levels.

A national average blends all of those. Quoted to a homeowner with the first house it is too high; quoted to the third it is far too low. The homeowner who negotiates a seller credit against a number from the internet and then discovers their house needs two suction points and a crawl-space membrane is the failure mode we are trying to prevent.

There is also a verification problem we will state plainly: we do not collect or audit contractor pricing data, and any figure we published would be either sourced from elsewhere or invented. Our editorial standards prohibit the second, and the first would mean repeating someone else’s number with our name on it.

What we publish instead

The drivers. Our cost pages describe what actually moves a quote, so a homeowner can look at their own house and understand why one bid is higher than another rather than assuming someone is overcharging.

The dominant factors are consistent: foundation type and how many soil-contact zones exist, whether a crawl space needs a sealed membrane, slab access and whether finished surfaces must be opened, the number of suction points a diagnostic indicates, routing distance and whether the pipe can run interior or must run exterior, fan selection against measured static pressure, electrical work and whether a permit is required, and whether post-mitigation verification is included in the price.

That list is also a comparison tool. Two bids that differ substantially almost always differ on one of those lines, and identifying which turns a confusing price gap into a specific question.

• Foundation type and the number of distinct soil-contact zones
• Crawl space membrane requirements
• Slab access, and whether finished surfaces must be opened and made good
• Suction points indicated by the sub-slab diagnostic
• Routing path — interior chase versus exterior wall
• Fan selection against measured static pressure
• Electrical work, disconnect, and any permit
• Whether the post-mitigation verification test is in the price

How local cost content is researched

Market-level cost pages describe which of those drivers dominate in a given metro, based on the housing stock and construction practice of that area — pre-war masonry in older river towns, hillside multi-level construction, tract slab-on-grade, farmhouse foundations combining three eras under one roof.

That is descriptive research about durable characteristics of the housing, not a claim about prevailing prices. When a page says bids in an area vary widely, it explains the structural reason — mixed foundation types, difficult access, a common crawl space — rather than quoting a spread.

How to get a number you can rely on

Written quotes from at least two credentialed contractors who have physically seen the house. On anything other than a simple poured basement, a phone quote is a guess, and a contractor who offers one without a site visit is telling you something about how they work.

Then compare the quotes on the driver list above rather than on the total. Ask each bidder to mark the suction point locations, the routing path, and the discharge point on the quote. Ask whether the verification test is included, and what happens if it comes back above the action level — that clause is worth more than a few hundred dollars of price difference.