The terms a mold pro will use, defined in plain English. We update this when we hear "wait, what does that mean?" on a call. If you encounter a term we haven't defined, send us a message and we'll add it.
Species + microbiology
Mold - A fungus that reproduces by spores. Lives anywhere there's moisture, organic material (cellulose: drywall, wood, paper, fabric), and time. Hundreds of species exist; ~50 commonly grow indoors.
Spore - The reproductive cell mold uses to spread. Microscopic, airborne, and present in essentially every indoor and outdoor environment. The question for any room is the count and the species, not "are there any spores."
Mycotoxin - A toxic chemical compound some mold species produce as part of their metabolism. Stachybotrys, certain Aspergillus, and Fusarium species are notable mycotoxin producers. Mycotoxins are what makes "black mold" different from cosmetic surface mildew.
Stachybotrys - Stachybotrys chartarum, the species most people mean when they say "toxic black mold." Slimy, dark green to black. Always indicates long-term water exposure. Mycotoxin producer.
Aspergillus / Penicillium - Two of the most common indoor mold genera. Often appear together. Most species are common allergens; some Aspergillus species can cause infection in immunocompromised individuals.
Cladosporium - Very common outdoor and indoor mold. Drifts in continuously from outside. Indoor levels are concerning when they exceed outdoor levels significantly.
Indoor marker species - Species that should NOT be present in higher concentrations indoors than outdoors. Finding marker species in an indoor air sample is a strong signal of an indoor source.
Mildew - Often used interchangeably with mold by non-experts, but technically refers to flat surface molds (the discoloration on bathroom grout or shower caulk). Different remediation pattern than structural mold.
Testing + measurement
Air sample - A measured volume of air pulled through a cassette with a sticky surface that captures airborne spores. Sent to a lab for species ID and counts per cubic meter.
Surface sample (tape lift) - A piece of clear adhesive tape pressed onto a visible mold colony, then mounted on a slide for microscopic ID.
Bulk sample - A piece of the affected material itself (drywall chunk, wood shaving, insulation tuft) sent to the lab for analysis.
ERMI - Environmental Relative Moldiness Index. A dust-based DNA test that analyzes settled household dust for 36 indicator species. Used when air sampling is inconclusive or when looking for chronic-exposure markers.
Spore count - Number of spores per cubic meter of air. Reported per species or as a total. Compared against outdoor baseline to determine whether levels are elevated.
Outdoor baseline / outdoor control - A sample collected outside the building at the same time as indoor samples. Used as the reference for "what's normal in this environment today." Indoor counts significantly above outdoor counts suggest an indoor source.
Lab report - The document from the testing lab listing species, counts, and methodology. Should always come on third-party-lab letterhead, not your remediation contractor's.
Clearance test - A final air sample taken after remediation to verify the work succeeded. Indoor counts should be at or below the outdoor baseline, with no marker species above incidental levels.
Accredited lab - A testing lab accredited by AIHA (American Industrial Hygiene Association) or equivalent. Accreditation means the lab has passed independent quality audits.
Standards + protocols
IICRC - Institute of Inspection, Cleaning and Restoration Certification. The standards-setting body for the remediation industry. Their certifications and standards are the floor for professional work in this field.
IICRC S520 - The IICRC's published standard for professional mold remediation. Defines containment, removal, drying, clearance, and documentation requirements. Look for "IICRC S520-compliant" in any quote you get.
Categories of water damage - Category 1 (clean water from a supply line), Category 2 (gray water, soapy or used water), Category 3 (black water, sewage or any unsanitary source). Higher categories require stricter sanitization protocols.
Classes of water damage - Class 1 (least, small area affected) to Class 4 (most, deeply saturated low-evaporation materials). Affects drying time and equipment needs.
Process + equipment
Containment - The plastic-and-tape barrier built around a work zone to prevent spore migration during removal. Should be sealed floor-to-ceiling with zippered access.
Negative pressure / negative air containment - Containment that uses a HEPA-filtered air scrubber to pull air out of the work zone faster than it comes in, ensuring any released spores can't migrate to clean areas.
HEPA - High-Efficiency Particulate Air. A filter that captures at least 99.97% of particles 0.3 microns in size. Mold spores are 2-30 microns, so HEPA captures essentially all of them. Required in air scrubbers and vacuums used during remediation.
Air scrubber / air mover - Equipment that filters air (scrubber) or moves air aggressively to dry surfaces (mover). Both run during a remediation job, often for several days.
Dehumidifier - Equipment that removes moisture from air. Commercial-grade units (50+ pints/day capacity) are required for remediation drying.
Source removal - Physical removal of the moldy material itself. The opposite of trying to "treat" or "kill" mold in place. Source removal is the IICRC-recognized standard; in-place treatment is not.
Encapsulation - Sealing affected material in place with a coating designed to prevent further spore release. Sometimes appropriate for inaccessible cavities; often pushed inappropriately on porous materials where source removal is the correct approach.
Fogging / ozone treatment - Spraying chemicals or ozone into the air to kill mold. Evidence for effectiveness in residential mold scenarios is poor. We don't sell either, and you should be skeptical of any contractor whose proposal centers on them.
Antimicrobial - A registered cleaning agent that inhibits or kills microorganisms. Used to wipe down hard surfaces after source removal. Not a substitute for source removal.
Reporting + documentation
Xactimate - The line-item estimating software insurance adjusters use to price damage claims. Quotes formatted in Xactimate are read directly by adjusters. We always provide Xactimate-formatted scopes for any insurance-involved job.
Scope of work - The written list of specific tasks the contractor will perform, with materials, units, and prices. Should be itemized, not lump-sum.
Change order - A written amendment to the scope when conditions change mid-job. Reputable contractors stop work, document, get your signature on a change order, then proceed. Beware contractors who proceed first and bill the changes after.
Clearance certificate - The final document at the end of a job certifying that the clearance test passed. Should reference the lab report by number and date.
Two-year warranty (or similar) - A commitment that the affected materials will not develop new mold growth for a defined period, conditional on the moisture source being resolved.
Term we should add? Send us a message and we'll cover it.