What Kills Mold? Products Professional Remediators Use

You searched for what kills mold. The results are mostly bleach. Or vinegar. Or a generic "call a professional" page with no information about what the professional is actually going to use on the wall.

Here's the unfiltered version. Three categories of products do the actual work on a remediation job: EPA-registered antimicrobials, encapsulant coatings, and post-remediation stain cleaners. Six specific products show up on most remediation trucks in the U.S., each with a registration number, a dilution ratio, a labeled dwell time, and a job it's good for. None of them are bleach. The chemistry is also the smaller half of the answer; HEPA air filtration, 6-mil polyethylene containment, and the IICRC S520 process do most of the actual killing on a real job. This guide names the products, the equipment, the process, and the surface-by-surface protocol pros use.

If you're cleaning a small patch yourself, our homeowner protocol covers the DIY scope under 10 square feet. This guide is for the next layer: what a competent remediator should be doing on the jobs that need one.

Drew Fuller, who reviews this guide, runs Restoration 365, an IICRC-certified remediation firm in Willow Grove, PA. Per the IICRC S520 standard he works to, the chemistry is the smaller half of the job; containment and HEPA filtration do most of the actual killing. Bleach is the most common mistake in homeowner DIY: the chlorine evaporates off porous surfaces before it penetrates, and only the water remains to feed the roots beneath. Most of the products on a truck are surface treatments. What actually gets rid of mold is removing the substrate it's growing on.

In This Guide

• The short answer: what kills mold (and what doesn't)
• Professional mold removal products: the 6 in a remediation truck (with EPA reg #s and dwell times)
• The equipment that does most of the actual killing (HEPA, containment, PPE)
• How professionals actually kill mold: the IICRC S520 process
• Surface-by-surface: what to use where
• What about black mold (Stachybotrys) specifically?
• What pros don't use (and why)
• When DIY ends and a professional starts

The short answer: what kills mold (and what doesn't)

Three categories of work matter on a remediation job. The chemistry is one of them, not all of them.

Physical removal plus HEPA filtration. The single most effective "kill" on a remediation job is removing the substrate the mold is growing on. Drywall comes out. Insulation comes out. Affected framing gets sanded or media-blasted back to clean wood. The mold doesn't get cleaned off porous materials; the porous materials get demolished and double-bagged. HEPA air scrubbing at 4 to 6 air changes per hour captures the spores that get airborne during demo.

EPA-registered antimicrobials. Surface treatment on the materials you're keeping. These are the products that do an actual chemical kill, with a labeled contact time and a registration number you can verify. Quat-based, phenolic, thymol-botanical, and sodium-hypochlorite formulations cover most of what's on a competent truck.

Encapsulants. A film-forming coating applied after cleaning to seal residual stains and prevent re-colonization on structural framing. Concrobium Mold Control and Foster 40-80 are the two most common. Encapsulants are a finishing step, not a kill step.

What doesn't work, on the jobs that need a pro: bleach on porous surfaces. The chlorine evaporates before it penetrates, and per the IICRC S520 standard, "the use of chlorine bleach is not a recommended means of treating mold contamination." Vinegar kills approximately 82% of mold species in lab conditions; it's fine for surface mildew on bathroom tile, inadequate for active growth on drywall. Tea tree oil works in a petri dish; it doesn't scale to a 200-square-foot containment.

What actually kills mold on a remediation job is mechanical removal. Chemicals are for the surfaces you keep.

Professional mold removal products: the 6 in a remediation truck

These six products show up on most U.S. remediation trucks. Five are EPA-registered antimicrobials with labeled dwell times; the sixth (RMR-86 Pro) is a sodium-hypochlorite stain remover applied AFTER the kill is already done. Each has a job it's good for. Most homeowners trying to "what kills mold" their way through a DIY project end up with the wrong product on the wrong surface; the spec sheet below maps each to where it actually belongs.

A few non-obvious notes. The 10-minute dwell time on quat-based and phenolic products is the single most violated step in DIY cleaning; spraying and wiping immediately wastes the labeled kill claim and leaves living spores on the surface. Concrobium and Foster aren't "kill" products in the disinfectant sense; they're encapsulants applied as a finishing step after the porous materials are out and the framing is HEPA-vacuumed clean. Fiberlock Shockwave also ships in a ready-to-use formulation (EPA Reg. No. 61178-2) for jobs that don't justify the concentrate-and-dilute workflow.

RMR-86 Pro is the product TikTok shows in before-and-after videos, and it's the one that confuses homeowners the most. It isn't EPA-registered as an antimicrobial because it isn't one; it's classified as a stain remover. The dramatic visible result is sodium hypochlorite bleaching the stain pigment, not killing live mold. RMR Solutions (the same brand) sells RMR-141 RTU Disinfectant as their EPA-registered antimicrobial counterpart for the actual kill step. Pros use RMR-86 Pro only after the kill is already done, for cosmetic stain cleanup on surfaces being kept.

EPA registration numbers above were sourced from manufacturer label PDFs and EPA records. Verify against the EPA Pesticide Product and Label System (PPLS) before relying on them for compliance purposes; manufacturers update registrations periodically.

The equipment that does most of the actual killing

The chemistry is the visible half of remediation. The equipment is the half that decides whether the job actually works or just smells better for two weeks.

HEPA air scrubbers and AFDs. Capture spores at 0.3 microns with 99.97% efficiency. A 500 to 700 CFM scrubber covers most residential containments at 4 to 6 air changes per hour, the IICRC S520 target. Without HEPA filtration during demo, the chemistry on the remaining surfaces doesn't matter if the air itself is loaded.

Negative-air machines plus containment. A HEPA scrubber configured to exhaust outside the work zone creates negative pressure inside containment, so air flows IN through any breach instead of dirty air flowing OUT. The containment itself is 6-mil polyethylene taped with red builder's tape, a zipper door, and poly over every HVAC supply and return inside the zone.

HEPA vacuums (not shop vacs). Standard shop vacs blow filtered-out particles smaller than the filter rating back into the room. A proper HEPA-rated vacuum captures and retains spores at 0.3 microns. Used on every surface inside containment before AND after antimicrobial treatment.

PPE. P100 or N100 respirators for active disturbance of suspected Stachybotrys (N95 is the floor for routine work but inadequate when mycotoxin-bearing fragments are airborne). Tyvek protective suit. Sealed goggles. Nitrile gloves. Per NIOSH guidance for mold cleanup, the PPE floor is set by the contamination level.

Why this matters more than chemistry: a homeowner spraying Benefect Decon 30 in an open room with no negative-air pressure is doing about 20% of the work a competent remediator does, while spreading 80% of the spores into the rest of the house. Same product, different outcome.

How professionals actually kill mold: the IICRC S520 process

The IICRC S520 Standard for Professional Mold Remediation is the document working remediators reference. It defines an 8-step process. A competent remediator follows it in order; a bad one skips containment or skips the moisture audit, which is where most jobs that "come back" actually failed.

1. Assessment plus moisture source identified. Before any chemistry, the water intrusion that grew the mold is located and slated for repair. A licensed mold assessor (different company than the remediator, per what an assessor does vs. a remediator) does this in the cleanest version of the job.

2. Containment plus negative pressure. 6-mil poly walls, zipper door, HEPA scrubber configured for negative-air exhaust. HVAC supplies and returns inside the zone sealed.

3. Source removal. Affected porous materials (drywall, insulation, carpet, ceiling tile, anything paper-faced) demolished, double-bagged in 6-mil contractor bags, removed through the containment exit. Wet vacuum on heavy contamination first to reduce aerosolization.

4. HEPA vacuum every surface. Every accessible surface inside containment vacuumed before any chemical treatment. Reduces the bioburden the chemistry has to handle.

5. Antimicrobial application. EPA-registered product applied to the surfaces being kept. Labeled dwell time observed; for most quat-based and phenolic products, 10 minutes minimum. Spraying and wiping immediately wastes the product.

6. HEPA vacuum again. Post-antimicrobial vacuum captures the killed spore mat and debris loosened during cleaning.

7. Encapsulant on remaining structural materials. Concrobium, Foster 40-80, or a similar antimicrobial coating sealed over the cleaned framing. Optional finishing step; locks down residual contamination at the surface and prevents re-colonization if minor moisture returns.

8. Post-remediation verification (PRV). Third-party clearance testing, independent of the remediator. An Air-O-Cell spore-trap cassette pulls a sample inside the cleaned containment; the lab compares it to an outdoor reference. The job passes when indoor counts are at or below outdoor baseline for the same species. A remediator who self-clears their own job has a conflict of interest.

Most homeowner-facing "how to kill mold" content skips steps 2, 6, 7, and 8. That's why DIY jobs at scale tend to come back within 60 days.

Surface-by-surface: what to use where

The single biggest reason DIY mold cleaning fails is using the wrong product on the wrong substrate. Each surface below has different absorption, different retention, and a different fix.

What kills mold on walls

Painted drywall is the most common wall mold question and the surface where DIYers go wrong with bleach. The paint film is non-porous on top; the drywall behind it is porous. Quat-based antimicrobials (Shockwave at 1:64) or thymol-based botanicals (Benefect Decon 30) are the right tools. Unpainted or wallpapered drywall is a different problem; the porous substrate has retained spores below the visible surface, and cutting it out is the actual fix. Bathroom-specific moisture sources behind wall mold are covered in bathroom mold.

What kills mold on wood framing or studs

Sanding plus an EPA-registered antimicrobial. The visible mold is sanded off with a HEPA-filtered random-orbit sander; the freshly exposed wood is treated with a quat-based product like Shockwave at full labeled dwell. For heavier contamination, dry-ice or soda blasting cuts through the spore mat without water. After cleaning, an antimicrobial coating like Foster 40-80 seals the framing. Attic and crawl-space framing has location-specific protocols; attic mold and crawl space mold cover those.

What kills mold on concrete or basement walls

Concrete is non-porous on the face and porous + alkaline at depth. Concrobium Mold Control is one of the few products formulated for the alkaline pH of concrete and concrete-block walls; sodium-carbonate chemistry doesn't fight the substrate the way sodium-hypochlorite chemistry does. Basement mold is almost always a moisture-source problem (foundation seepage, sump-pump failure, dryer vent disconnected inside the wall cavity). Basement mold causes and solutions covers the moisture audit.

What kills mold on HVAC or ductwork

HVAC mold is a different protocol entirely. Per CDC mold cleanup guidance, ductwork requires specialized cleaning homeowners can't replicate; the spore distribution is uniform on every cycle, and duct interiors can't be accessed without a NADCA-certified duct cleaner. The kill chemistry is usually an antimicrobial coating on sheet metal. HVAC mold is a professional job regardless of square footage.

What kills mold spores in the air

HEPA filtration, not chemistry. A 500 to 700 CFM HEPA scrubber running at 4 to 6 air changes per hour, then a post-clearance run before PRV sampling, is the protocol. Aerosol kill claims on consumer "mold bombs" are not validated against the spore load demolition creates.

What about black mold (Stachybotrys) specifically?

Black mold isn't killed with a different chemistry. The same EPA-registered antimicrobials work on Stachybotrys chartarum as on Aspergillus, Cladosporium, or Penicillium. What's different is the containment, the PPE, and the disturbance threshold.

Per CDC guidance, Stachybotrys produces mycotoxins that disturbance aerosolizes. P100 or N100 respirators (not N95). Full Tyvek. Wet the surface before any scrubbing to reduce aerosolization. The disturbance threshold is lower; 10 square feet is the published EPA threshold for any mold, but for suspected Stachybotrys most remediators tighten it to the smallest patch that can be handled with full containment.

For the full Stachybotrys-specific protocol, see the full Stachybotrys removal guide. The decision tree (what makes black mold a pro job) and the medical-PPE rationale belong there, not duplicated here.

What pros don't use (and why)

A short list of products that show up on consumer shelves and homeowner forums but not on competent remediation trucks.

Bleach. The most popular home mold cleaner, and the most common mistake. Per IICRC S520, the chlorine evaporates off porous surfaces before penetrating; only the water remains, which feeds the roots below. Per CDC mold cleanup guidance, chlorine bleach is not generally recommended as a routine practice. It works on tile and glass; it fails on drywall, wood, grout, caulk, fabric, paper, and insulation. "Looks gone" is not the same as "is dead."

Ammonia. Same porous-surface problem as bleach, plus the dangerous-mixing issue (mixing ammonia and bleach produces chloramine gas, which is acutely toxic).

Tea tree oil and essential oils. Lab petri-dish studies show antifungal activity. The application concentration that achieves a meaningful kill on a 200-square-foot containment is impractical, and the products aren't EPA-registered as antimicrobials.

Vinegar. 5% acetic acid kills approximately 82% of mold species per published research. Fine for surface mildew on bathroom tile or grout; inadequate for active growth on drywall, since the 18% that survive include common indoor problem species. The full vinegar breakdown covers when it's the right call.

Borax. Mild antifungal activity. Not EPA-registered as an antimicrobial. Decent for laundry; not used on remediation jobs.

When DIY ends and a professional starts

Five triggers flip the answer to "call a professional" regardless of how small the patch looks.

Patch over 10 square feet. The EPA's published threshold for homeowner DIY is mold covering less than a 3-by-3 foot area on hard surfaces. Anything beyond that requires containment, HEPA filtration, and trained protocols the homeowner doesn't have.

Porous material involved. Drywall, carpet, insulation, ceiling tile, fabric, paper-faced anything. Porous substrates retain spores below the visible surface; cleaning the face leaves the colony in place. The fix is removal and replacement, not cleaning, and removal at scale requires containment.

HVAC contamination. Mold inside ducts, on the air handler, or in the condensate pan spreads spores throughout the entire home every cycle. Per CDC guidance, HVAC mold requires NADCA-certified duct cleaning. Always a professional job.

Post-flood or Category 3 water. Per IICRC S500 Standard for Professional Water Damage Restoration, Category 3 water (sewage, flood, groundwater intrusion) carries pathogens beyond mold. The remediation protocol changes; it's not a homeowner job.

Health symptoms in occupants. If anyone in the household has unexplained respiratory symptoms that improve when away from home, the air-quality risk during disturbance is real. Professional containment with HEPA filtration protects the rest of the household; DIY disturbance doesn't.

If any of those triggers apply, the next steps are: what an assessor does vs. a remediator (you usually want both, as separate companies), how to hire the right remediator, questions to ask before you sign, common remediation scams to watch for, and typical remediation pricing. For the full DIY-vs-pro decision framework with the moisture-source angle, see the DIY-vs-professional decision threshold.

Once the existing mold is handled, preventing regrowth covers the humidity-control and moisture-monitoring protocols that make the kill last.

Next steps

If the patch you're looking at fits inside the DIY scope (under 10 square feet on a hard, non-porous surface, no HVAC involvement, no health symptoms), the homeowner protocol walks through the moisture-source audit, the product choice, and the cleaning steps. If any of the five triggers above applies, the next step is finding a remediator who works to the IICRC S520 standard and an assessor who works independently.

Find a Verified Mold Professional

Every mold remediator in our coverage has been license-verified, insurance-verified, and tier-ranked. Verified mold professionals in your state are the directory entry point.

This guide is for educational purposes only and is not a substitute for professional advice. EPA registration numbers in the product spec table should be verified against the EPA's product label search before relying on them; manufacturers update registrations periodically. Always consult certified professionals for specific mold situations in your home.