What Happens During a Mold Inspection

A residential mold inspection takes one to two hours on site, produces verbal findings before we leave, and ends with a written report about two to four business days later once the lab has run the samples. Larger or more complicated buildings run three to four hours on site.

Here is the whole sequence, including the parts you are responsible for.

Before you book: the phone call

Call and describe what is going on. What you smelled and when. What got wet. What the home inspector wrote. Whether anyone in the house is reacting and whether it stops when they leave.

That conversation decides three things: whether testing will actually answer your question, how many samples the building probably needs, and what it will cost. If testing will not help you, we say so on the phone. The most common example is visible growth on a surface you already know is wet. You do not need a lab to identify what you are looking at. Fix the water, clean the surface, keep the money.

If testing does make sense, you get the price before we schedule. A standard inspection is $425 with one indoor air sample and an outdoor control, additional samples $100, homes over 3,000 square feet $550 to $650, and no trip fee anywhere.

What to do before we arrive

Air sampling measures the air as it normally is, and a few ordinary household activities distort that badly.

Keep windows and exterior doors closed for at least four hours beforehand. An open window pulls the outdoor spore profile inside, and your indoor sample starts to look like your outdoor control, which erases the comparison the whole test depends on.

Do not vacuum, dust or sweep that morning. It lifts settled spores into the air and can multiply an indoor count several times over. So can shaking out rugs.

Do not change the pattern on air purifiers, dehumidifiers or the HVAC. If they normally run, let them run and tell us. If they are off, leave them off. What ruins the data is switching the routine on the day.

Leave the suspect area alone. No bleach, no scrubbing, no painting over it. Cleaning it destroys the evidence and does not fix the water.

Provide access to the crawlspace hatch, attic, utility room and under sink cabinets. You do not need to leave the house, and neither do pets.

The interview

The visit starts with ten to fifteen minutes of questions, and this is not small talk. Most of the diagnosis lives in the timeline. When did you first notice it. Did it follow a freeze, a storm, an appliance failure, a roof repair. Which room is worst. Has anything been repaired, by whom, and did it help. If you have the home inspection report, the claim file, prior test results or contractor invoices, have them out.

The walkthrough

Then we walk the building, inside and out.

Outside first, because water almost always starts there. Grading and whether the ground falls away from the foundation. Downspout terminations and whether they discharge to daylight or straight against the wall. Gutters. Roof edges, valleys and penetrations. Siding at the base of exterior walls. Foundation vents, window wells, and irrigation heads aimed at the house.

Inside, every accessible area, with attention to where water actually goes. Under sinks and behind toilets. Dishwasher, refrigerator and washing machine lines. The water heater pan. Window sills and door thresholds. Basement rim joists. The attic, especially where bath fans terminate and where ice dams push meltwater backward under the shingles. And the crawlspace, which in pre-1970 housing is where a large share of Inland Northwest problems live, because vapor barriers are frequently missing, torn, or were never installed.

We photograph as we go, and those photos end up in the report with captions and locations.

Moisture mapping, thermal and the borescope

Mold is a symptom. Water is the disease, and this part of the visit is about finding the water.

Pinless meters scan intact surfaces without damaging them. We sweep drywall, subfloor, sheathing and framing looking for the anomaly rather than the absolute number, because material and density both shift the reading. Pin meters probe where we can, giving percentage moisture content in wood at a known depth. Every suspect reading is paired with a reference reading from known dry material of the same type, and recorded with its location, because a wet spot with no location is not evidence.

Thermal imaging reads surface temperature, not moisture. Evaporation cools a surface, so a cavity holding water usually reads colder than the material around it, and the camera shows that pattern across a whole wall in a second instead of one probe at a time. It also finds missing insulation and cold spots where condensation forms. Thermal is a search tool, and anything it flags gets confirmed with a meter before it becomes a finding.

The borescope settles cases where the meter and the camera disagree, or where the suspect space is a sealed cavity, a chase or a soffit nobody can reach. A quarter inch hole in an inconspicuous spot beats guessing, and beats opening a wall to find nothing. We ask before we drill. Always.

Psychrometrics finish it: temperature, relative humidity and dew point in each zone and outside. Relative humidity alone is misleading because it moves with temperature. Dew point tells us where condensation will form, which is how a crawlspace at 55 degrees soaks a subfloor while the living room feels perfectly dry.

Where the samples go and why

Air samples are collected with a calibrated pump drawing a measured volume of air through a spore trap cassette, either Air-O-Cell or Allergenco-D, which traps particles on an adhesive slide that a lab analyst reads under a microscope.

Placement is deliberate. Samples go in the breathing zone, three to five feet off the floor, mid-room rather than in a corner, away from supply registers, fans and open doorways that create turbulence. We sample the complaint area, plus a comparison area in the same building with no complaint. We do not sample four rooms to generate four numbers.

Surface samples get taken where there is visible material and a real question about what it is. A tape lift or swab settles whether that stuff is fungal growth or soot, efflorescence, overspray or dust. Often the cheapest way to end an argument.

And an outdoor control, on every single job. Taken upwind of the building, the same day, in the same weather, included in the base price and never optional. Outdoor air always contains mold spores, everywhere, all year, so an indoor count in isolation cannot be interpreted. Three hundred spores per cubic meter of Cladosporium indoors is unremarkable on a September afternoon in Spokane when outdoor counts are in the thousands, and a serious finding in February when snow cover has driven outdoor counts near zero. Reports with no same day baseline get sold here constantly, and they are not something you can act on.

Chain of custody and the lab

Each cassette is labeled at collection with the sample identifier, location, date, time, pump flow rate and volume drawn. Those entries go on a chain of custody form that travels with the samples, records every transfer, and is signed by the analyst on receipt. That form is in your report, and it is what makes the lab data defensible in front of an adjuster, an attorney or a court.

Samples go to an accredited laboratory for direct microscopic examination. An analyst counts and identifies spores by genus and reports concentrations in spores per cubic meter, plus a note on debris load. Turnaround is normally one to three business days, with rush 24 hour handling for $100.

Before we leave the property

You get verbal preliminary findings on site. Where the moisture is, what the thermal camera showed, what we saw in the crawlspace, and what we are still unsure about. If there is something to do immediately, like shutting off a supply line, you hear it that day rather than in an email next week. What we cannot tell you on site is what is in the air. That takes the lab.

The report, and what happens after

Your written report follows within a day of the lab results: site conditions, moisture and psychrometric readings with locations, captioned photographs, raw lab data, the chain of custody form, the indoor to outdoor comparison, plain language findings, and recommendations.

It does not include a remediation bid, because we do not sell remediation. Instead it describes the problem precisely enough for any qualified contractor to scope and price, plus what IICRC S520 expects for that class of work, so you can tell whether the bids you get match the findings.

If results are normal, you have a dated document saying so, worth having in a purchase, a rental dispute or an insurance file. If results are elevated, take the report to two or three contractors and get bids against it. We will walk through the findings with any of them, or with your adjuster, agent or attorney, at no charge, and we do not recommend a specific company because we are not paid to. If remediation happens, get the finished work verified by somebody who did not do it. Clearance testing is $375 flat for up to three samples.

Book an inspection

Tell us the address, what you are seeing or smelling, and how soon you need results. We will tell you what it costs before we schedule, and whether testing is the right tool.

Questions about the process

How long does the visit take? A typical residential inspection is one to two hours on site. Larger or more complicated buildings run three to four. Post remediation clearance testing is 45 to 60 minutes because the area is already defined.

Why do you always take an outdoor sample? Because outdoor air always contains mold spores, so an indoor number by itself cannot be interpreted. Elevated means elevated relative to outside your own building on that day. A report with indoor counts and no same day outdoor control is not something you can act on.

What equipment do you actually use? A calibrated air sampling pump drawing a measured volume through a spore trap cassette, pin and pinless moisture meters, a thermal imaging camera, a borescope for wall cavities, and a psychrometer for relative humidity, temperature and dew point.

Who analyzes the samples? An accredited independent laboratory, by direct microscopic examination. We collect and document. We do not analyze our own samples, which is part of why the result is defensible.

Will the report tell me what to do next? It describes the conditions found, the laboratory data, and a recommended scope in terms any qualified remediator can bid against. It contains no remediation bid, because we do not sell remediation.