Buyer Tests the Trades Get Pulled Into

Why this matters

A general home inspection is a visual survey, and when it hits something outside its depth it hands the buyer a recommendation for a specialist test. Four of those tests land on trade shops again and again: radon, mold, sewer scopes and chimney inspections. Sometimes you are the one asked to run the test; more often you are the plumber, HVAC tech or electrician who happens to be in the house, and the agent asks you what the result means and whether you can fix it. Each test has its own rules about who may perform it, what number matters, and what a trade can say about it without stepping outside its license. Get that wrong and the cost is not a callback; it is a voided test that delays a closing, or a written statement you were not qualified to make sitting in a buyer's file.

The four tests on one card

The rest of this card takes them one at a time, then covers what to keep out of your own paperwork.

Radon: a number with a protocol behind it

Radon is a radioactive gas from uranium in soil that enters through slab cracks, sumps and gaps around pipes. It is measured in picocuries per liter (pCi/L) of air. EPA, at the federal level, recommends fixing a home at or above 4 pCi/L and suggests considering it between 2 and 4. That action level is guidance, not a regulation that binds a homeowner; what binds the people doing the work is the state layer. Some states license or certify radon testers and mitigators (Illinois and Pennsylvania, for example), many have no requirement at all, and national credentialing bodies fill the gap. Check your own state before you sell either service.

A real-estate radon test is usually a short-term test of at least 48 hours run under closed-house conditions: windows and exterior doors closed except for normal coming and going, starting 12 hours before a test under four days, per EPA's home buyer guidance. That protocol is where trades get pulled in by accident:

• An HVAC tech who props the basement door open for an hour, runs a fresh-air ventilator on boost, or leaves a crawlspace access open can change the result. Many test devices and continuous monitors record tampering or movement, and a flagged test is redone, which can cost the buyer days against a contingency deadline.
• A plumber who opens a sump lid or a floor drain cleanout during the test exposes a direct soil-gas path.

What a trade can legitimately do: an electrician can wire a mitigation fan circuit, an HVAC shop can balance or add ventilation that a mitigator specifies, a plumber can seal a sump lid with a gasketed cover. What the trade should not do, unless it holds the state credential where one is required: design the mitigation system or tell a buyer a number will drop below 4 after your change. The only proof is a retest after the work.

Mold: no federal number, a state license in some places

There is no federal limit for mold in a home, and EPA does not set one. What EPA does publish is cleanup guidance that uses roughly 10 square feet of contiguous growth as the line above which it recommends following its fuller remediation guide rather than a small homeowner cleanup. Treat that as a size cue, not a pass mark.

The state layer here has teeth for trades. Texas and New York license mold assessors and remediators and generally prohibit the same company from assessing and remediating the same project; Florida licenses assessors and remediators. Many states have no mold licensing at all. In a conflict-of-interest state, the shop that writes "mold present, remediation needed" may be barred from then selling the remediation.

Where trades get pulled in is the cause, which is almost always water: a supply leak, a condensate line, an uninsulated duct sweating in an attic, a dryer vent dumping into a crawlspace. That is your lane, and it is valuable. You can find and fix the moisture source, and you can record moisture readings and what you saw.

Sewer scopes: when you are the specialist

A sewer scope is a camera run down the lateral, the private line from the house to the public main. The plumber or drain shop usually is the specialist here, so the risk is not overstepping into someone else's license but overstating your own findings. Two lines to hold:

• Know where the private line ends. Ownership of the lateral, and of the connection at the main, is set by the local utility and varies city by city. Say "to the main" or "to the property line" only if you know which, and never describe the condition of pipe you did not see.
• Code defects with a shared vocabulary. Many shops use NASSCO's PACP (Pipeline Assessment Certification Program) defect codes or its plain-English equivalents: belly, offset joint, root intrusion, crack, fracture, collapse. A named defect at a stated distance is worth more to a buyer than "line in poor condition."

Turning the scope into a defined product with a fixed scope and report is its own job. See related: Scoping a Specialty Pre-Purchase Inspection.

Chimneys: the appliance in the flue is yours, the flue is not

NFPA 211, the standard for chimneys, fireplaces and vents, defines three levels of inspection. Level 1 is a readily accessible visual check; Level 2 adds a camera inspection of the flue's interior; Level 3 involves removing parts of the building. The standard calls for a Level 2 inspection upon sale or transfer of a property. That requirement binds only where NFPA 211 has been adopted, in the edition your jurisdiction adopted; elsewhere it is industry practice that inspectors cite and buyers expect.

The trade pulled in here is usually HVAC or plumbing, because a furnace or water heater vents into a masonry chimney. The vent connector, draft, and whether the appliance's venting tables allow that flue are yours. The masonry, the crown, the flue tiles and the liner condition belong to the chimney specialist. An HVAC tech who looks up from the cleanout with a flashlight and writes "flue OK" has performed less than a Level 1 and signed a Level 2 conclusion.

What stays out of your written note

The sharpest part of working near these tests is what you deliberately do not put on paper, because your note goes into a transaction file and gets read by people deciding a sale. Five exclusions, each with its reason:

• No interpretation of a test you did not run. "Radon 4.6, that's not bad" from an HVAC tech becomes the buyer's evidence that a trade said it was fine. Your note says what you saw and did.
• No health claims. Whether a level of radon or a patch of growth is dangerous to this family is outside every trade license. Say "above EPA's action level" or "visible discoloration on the joists, about 2 square feet," and stop.
• No species, no "black mold." Identifying a mold takes a lab. Describe color, area, and location.
• No conclusion past your access. If you saw 30 feet of a 60-foot lateral, the report says 30 feet.
• No promised outcome. "This will fix the radon" is a warranty of a retest result.

What you do put in: the date, what you were there for, what you observed with measurements, what you did, and anything you did that could affect a running test.

Worked case: the tune-up during the radon test

A seller books an HVAC tune-up three days before inspection deadlines close. The tech arrives Wednesday at 10 am to find a continuous radon monitor on a basement shelf and a "closed-house test in progress, started Tuesday 9 am" sign. That is 25 hours into a 48-hour test.

On arrival. The tech does not move or touch the monitor, and comes in through the normal entry door, closing it behind them. The tune-up needs about 1.5 hours and two trips to the truck, both through the same door, both closed promptly. That is normal entry under the protocol. The fresh-air intake damper on the system is left at its existing setting. The job note records: test device present, not touched, two normal-entry door openings, no windows opened, ventilation settings unchanged.

What the tech found. The furnace vents into an unlined masonry chimney with a water heater. The tech can see spalled tile fragments at the cleanout. The tech's note says: "Flue debris at base of chimney cleanout, appears to be tile fragments. Flue interior not inspected. Recommend Level 2 chimney inspection by a chimney specialist before relying on this flue for venting." The tech does not write that the flue is failing, only what was seen and who should look. Fallen tile can mean a partial blockage, so before leaving the tech confirms draft at both appliances and watches a CO meter at the draft hood while they fire; a failed draft test or rising CO means the appliance is shut off and tagged out of service, and the seller is told in person, which would be the first line of the note instead.

Two days later. The test reports 4.6 pCi/L, above the 4 action level. The seller's agent calls and asks whether the HVAC shop can "fix radon" before closing. The shop is in Pennsylvania, where radon mitigation requires state certification, and it holds none. The answer is no, with a referral to a certified mitigator, and an offer to do any HVAC work the mitigator specifies. In a state with no radon licensing the legal bar is gone, but the practical answer is the same unless the shop has trained for it: the result that matters is a retest after mitigation, and a shop that sells the fix without a retest has sold a promise it cannot check.

The failure version is common. The tech props the door for the half hour of tune-up work, the monitor logs a pressure drop, the test is invalidated, and a retest needs another 48 hours the contract may not have.

How to check your own handling

Pull the last three jobs your shop did in a house under contract. For each, did the note say what you were there for, what you saw with a measurement, and what you did that could affect a running test? Did any note interpret a result you did not produce, or reach past what you could see? Then confirm, for your state, whether radon and mold work need a license and whether a conflict rule applies, and write the answer where your office sees it at booking.

References

• EPA, Home Buyer's and Seller's Guide to Radon (action level, short-term testing, closed-house conditions).
• EPA, Mold Remediation in Schools and Commercial Buildings, and A Brief Guide to Mold, Moisture and Your Home (size guidance).
• NFPA 211, Standard for Chimneys, Fireplaces, Vents and Solid Fuel-Burning Appliances, in the edition your jurisdiction has adopted.
• NASSCO Pipeline Assessment Certification Program (PACP) defect coding.
• See related: Reading a Home Inspection Report as a Trade