High radon isn't a mystery. It's a foundation and fan problem

EPA's action level is 4 pCi/L. If a valid test on this house sits at 4 or above, plan on mitigation. Confirm the test was honest first: right room, closed house, enough hours. Then get a quote for this foundation, not a national average. Call (423) 455-9162 with the foundation type and the number on the report.

A 3.8 and a 4.2 are the same conversation. A 12 is a different one. We will not treat a Zone 1 map as a fail for your address, and we will not promise a pretty number before we see the crawl. The Zone 1 for buyers page is the map speech. This page is what you do after the number.

Confirm the test before anyone cuts a slab

People say "failed" the way they say a home inspection failed. Radon is a measurement. Ask:

• Was the device in the lowest lived-in level, not a garage, not a crawl you never enter, not a windowsill?
• Were windows and big exhaust fans actually closed?
• Did a continuous monitor log the hours, or is this a charcoal kit someone might have opened early?
• If you're in a purchase, was it a contract-grade test? Kits are easy to mishandle in a deal. The real estate testing page is the file both sides can defend.

If the first look was a TDEC kit in a house you already occupy, we often confirm with a professional test before we design a system. If the continuous monitor already ran closed-house for about 48 hours, we do not make you retest for sport. We use that number.

What usually changes on a Johnson City foundation

Most ranches here sit on a dirt crawl. Proper work is usually sub-membrane depressurization: sealed polyethylene over the soil, suction under the plastic, a continuous fan, exhaust above the roof, and a manometer you can see. A box fan in a foundation vent is not a system.

A basement or a Boones Creek slab gets a pipe through the concrete and a pit in the gravel. Concrete is a lid with joints, not a radon shield.

Hillside houses toward Buffalo Mountain and the Boones Creek ridges often have both: walkout basement downhill, crawl or slab uphill. Those two volumes do not share soil gas. A single pretty pipe on the basement wall can clean one side and leave the other sitting high. We look at both faces. That is the job that takes longer to design, and it is why you should not wait until the last Wednesday of the inspection window.

Jonesborough stone crawls and split additions are the same idea with messier details. Send the foundation, not a photo of the street. The mitigation page is the systems explainer. This page is the handoff after the number.

Who pays in a Tennessee deal

Tennessee does not assign radon mitigation to the buyer or the seller. There is no state rule that the seller has to fix it before closing. Typical paths we actually see:

1. Seller installs before closing, then you retest.
2. Seller credits money and the buyer takes the system on after closing.
3. Buyer accepts the number and budgets the work themselves.

Which path wins is negotiation, inspection-window math, and how ugly the foundation is. We write the quote and the system. We do not write the contract. If you need a number both agents can forward, call (423) 455-9162 with the test result and whether the house is vacant.

Timeline honesty

A straightforward ranch crawl or a simple slab can often be quoted, installed, and retested inside a normal closing timeline if you start when the report lands, not the week of the walkthrough.

Split hillside foundations, historic stone crawls, and houses that need electrical run for the fan take longer. We will say so up front. Do not assume a Buffalo Mountain walkout is a two-day ranch job.

What it usually costs (market range, not a bid)

Straightforward crawl or slab jobs in this region often land somewhere between $800 and $2,500. Split hillside foundations and historic stone crawls run more. That is the same market range we already publish on the mitigation page. It is not a bid for your house.

Outside research for Johnson City sometimes quotes a tighter band for a typical fan-based install, roughly $825 to $1,258 on aggregator pages, and broader Tennessee industry writeups often talk about $1,000 to $2,500. Treat those as market chatter. They exclude ugly electrical, extra suction points, and the house we have not walked. Send the foundation and the test number for a real quote.

After the fan: retest and the manometer

A finished job should leave you with a running fan, a U-tube manometer you can see, a label on the system, and a post-mitigation test after the house has settled. That retest is how you know the pressure field is doing the work. We do not skip it. We do not promise a guaranteed reading such as "under 2.0" before we see the foundation.

When the fan dies years from now, replace it and retest. The house does not become immune.

If you already have a high number, skip the geology lecture. Send the town, the foundation, and the test result. Call (423) 455-9162 or request a quote.