What Does an Alert Mean?
Mold gives off scent compounds as it grows. A trained detection dog, or mold sniffing dog as plenty of people call them, picks those up at levels no handheld meter can read, through drywall, under flooring, and around ductwork. An alert means one thing: the dog detected mold odor at that spot. The alert turns "something smells off in this house" into "look at this wall."
What a Sweep Is Not
We are a detection service, and we stay in that lane on purpose. A sweep doesn't determine whether mold is definitely present, what species it might be, how far it extends, or whether you need remediation. Florida licenses mold assessors to answer those questions with testing. If you want that certainty, hire a licensed mold assessor. What the sweep changes is the order: run the sweep first at a lower cost, then pay for assessment only at the spots where the dog alerted. The full sweep-versus-testing comparison spells out which one you need first.
Can a Dog Really Smell Mold Through a Wall?
Yes, and the reason is plain physics. As mold grows, it releases gases called microbial volatile organic compounds, which is the technical name for that musty smell. Those gas molecules don't stay put. They drift through wall cavities and slip out through outlets, baseboards, gaps, and seams, the same way you can smell coffee from another room. The amounts that escape are far too small for a person to notice, but a dog's nose works at levels thousands of times below ours. The dog reads what the wall is leaking and follows it to where it is strongest.
This is why the sweep works without opening anything. The evidence comes out of the wall on its own. The dog just knows how to read it, and the handler knows how to read the dog.
Which Sweep Do You Need?
Most jobs are a standard home or business sweep. If you are buying a house, the pre-purchase sweep fits inside your inspection period. If you already paid for mold work, the post-remediation re-sweep tells you whether the dog still alerts where it used to. And if you manage rentals, the landlord and property manager page covers how sweeps settle tenant complaints. Not sure how the sweep compares to testing? That comparison is here.
What the Alert Summary Includes
The alert summary is a written record of the sweep. For each alert, it lists the room and describes the spot where the dog alerted, in plain language you can hand to anyone: the wall behind the master closet, the base of the kitchen island, the ceiling corner near the AC return. If the dog went through a room without alerting, the summary says that too, because a documented clean room is information you paid for.
The summary arrives promptly after the visit, not weeks later. People use it three ways: as the target list for a licensed mold assessor's testing, as the work order for a repair aimed at the moisture source, and as the before-picture for a re-sweep after the work is done.
How Should I Get Ready for the Visit?
Not much is needed. Keep your own pets crated or outside while the dog works, because another animal in the room distracts a working dog. If you know the trouble spots, the smells, or the history of leaks, tell us before we start. And don't air the house out that morning. A closed-up house holds the odor, and the odor is what the dog reads.