How we made this guide: picks, prices and specs come from our catalog and the makers' published specs, owner quotes come from customer reviews on our product pages and every guide is checked and edited by Trevor Hall.
The mold remediation process runs in one order: fix the moisture source, contain the area, run negative air, remove the moldy material, HEPA-vacuum and wipe, dry, make a final HEPA pass and pass clearance before anything is rebuilt. For a patch under about 10 square feet the EPA's homeowner guide says you can in most cases do it yourself. Beyond that, its guide for schools and commercial buildings calls for containment and a remediation manager, usually a trained crew or contractor.
Quick answer
Nine steps, in this order: find and fix the water, plan and size the containment, protect people and build the containment, run negative air, prove the room stays negative, remove what cannot be cleaned, HEPA-vacuum and wipe, dry the structure, then make a final HEPA pass and clear the space. A small patch can be a single day with a respirator, gloves, goggles and a HEPA vacuum. A contained job runs for days with negative air, a pressure monitor and a dehumidifier. Machines contain the dust, capture it and dry the structure. For the full kit by job size, see our mold remediation equipment guide.
Equipment at each step
| Step | What it does | Equipment |
|---|---|---|
| Protect | Keeps dust off workers | N-95 or HEPA-cartridge respirator, gloves, goggles, disposable suit |
| Find the wet edge | Locates moisture before demolition | Moisture meter and thermal camera |
| Contain | Seals the work area | 6-mil fire-retardant poly with a slit entry and flap; double poly and an airlock or decontamination chamber for large jobs |
| Negative air | Keeps airflow moving into the containment | HEPA negative air machine with ducting |
| Monitor | Shows the room stays negative | Room pressure monitor |
| Clean up | Captures dust left after removal | HEPA vacuum |
| Dispose | Seals removed material | 6-mil poly bags |
| Dry | Brings the structure back to normal readings | Dehumidifier |
Step 1: Find the moisture and fix it
Mold needs moisture, so the first job is the water, not the mold. The EPA advises drying wet areas and belongings inside 24 to 48 hours, before growth can start. If the water is still there, anything you clean will grow back.
A moisture meter and a thermal camera find the wet edge before you open a wall. The FLIR MR176 Remediation Imaging Moisture Kit pairs the MR176 imaging moisture meter (80 x 60 pixel thermal image) with a FLIR E6 camera. Its relative humidity accuracy is listed at plus or minus 2.5% RH. For other meters, browse the moisture meter collection and read our moisture meter readings chart to know what a normal reading looks like on drywall, wood and concrete.
Find the wet edge
FLIR MR176 Remediation Imaging Moisture Kit 6
$3,279
Scan with the thermal image first, then confirm with the pinless sensor or the external pin probe before you cut anything.
Step 2: Plan the job and size the containment
Measure the visible growth, then pick the containment. The EPA's guidance for schools and commercial buildings sets tiers by the size of the contaminated area, and it adds that a heavy growth of mold in a relatively small area could release more spores than lighter growth over a larger one, and that choice of containment should be based on professional judgment. On larger jobs, a mold assessor or indoor environmental professional often inspects first and writes the protocol the contractor works to.
| Area of mold | Who usually does it | Containment (EPA guidance) |
|---|---|---|
| Under about 10 square feet | A trained owner or staff member can often handle it | None required (EPA Table 2); minimum protection is an N-95 respirator, gloves and goggles |
| 10 to 100 square feet | A trained crew under a remediation manager (EPA), often a contractor | Limited: a single layer of 6-mil, fire-retardant polyethylene sheeting with a slit entry and covering flap, under negative pressure from a HEPA-filtered fan unit exhausted outside the building |
| Over 100 square feet | A trained crew under a remediation manager (EPA), usually a remediation contractor | Full: double layers of polyethylene, a decontamination chamber or airlock and negative pressure from a HEPA-filtered fan unit exhausted outside the building |
The do-it-yourself limit
Stay under about 10 square feet, fix the water first and wear the minimum protection the EPA lists: an N-95 respirator, gloves and goggles without ventilation holes. If the mold is behind finished walls, in the HVAC system or on sewage-contaminated material, stop and call a contractor. Do not run the HVAC system if you suspect it is contaminated. Anyone with health concerns should check with a doctor first, per the EPA. This post is not legal or medical advice.
Professional mold work is usually written against ANSI/IICRC S520, the IICRC's standard for professional mold remediation. Read the standard itself before you cite it in a contract. We do not call any machine S520 compliant.
Step 3: Protect people and set up containment
Before any demolition, shut off and cover supply and return vents in the work area, seal the doorways and build the barrier the size table calls for. The EPA bases protection on the size of the contaminated area. For a small area its minimum is an N-95 respirator, and it says to always use gloves and eye protection. Limited protection is a half-face or full-face air-purifying respirator with a HEPA filter cartridge, and disposable paper overalls can be used. Full protection is a full-face powered air-purifying respirator (PAPR) and a body suit of breathable material. Areas of 10 to 100 square feet take limited or full protection by professional judgment, and areas over 100 square feet take full protection.
Full containment adds a decontamination chamber so workers can strip off coveralls before they leave. The Abatement Technologies EASY UP decontamination shower is a collapsible example. Our guide to decontamination showers covers them, and what ICRA is covers the barrier classes healthcare sites ask for.
Step 4: Run negative air
The EPA says the containment area must be kept under negative pressure relative to the surrounding areas. A HEPA negative air machine pulls air out of the containment through its filters, and the EPA's guidance has that air exhausted outside of the building. The EPA guide says that if the containment is working, the polyethylene sheeting should billow inward on all surfaces, and if it flutters or billows outward, containment has been lost.
The Novatek Novair 1000 Variable Speed is the single-room machine in this guide. Novatek's operation manual says the dial sets airflow anywhere from 1,000 cfm down to 100 cfm, and our listing gives that range with all filters installed. The machine has a 16 x 16 inch metal mini-pleat HEPA filter, a pleated carbon filter and a two-ply ring filter. It draws 5 amps at 115 V, and the manual calls for a dedicated 10 amp, 110/115 V circuit. The exhaust collar is 10 inches, so match the ducting to that size. Ducting such as Novatek Duct-2-Go packs into its own carry case and carries the exhaust out of the building. Three versions are listed: HEPA only, HEPA with alarm and light or HEPA with alarm, light and hour meter. The gauge on the front reads filter loading, not the room's pressure. Per Novatek's manual, it reads negative pressure downstream of the filters, and the alarm versions sound at 1.6 to 1.8 inches of water column when filters load or airflow drops.
More machines are in the negative air machines collection. Our air scrubber comparison for mold work lines up eight of them. For setup, see air scrubber vs negative air machine, and for the physics, what a negative pressure room is.
Negative air for one room
Novatek Novair 1000 Variable Speed HEPA Air Scrubber and Negative Air Machine
From $1,195
Speed dial from 100 to 1,000 cfm, so you can set the draw to the containment. Weighs 94 lb as listed.
Step 5: Prove the room stays negative
Poly that billows inward is a good sign, but it is not a record. A room pressure monitor reads the pressure difference between the containment and the space next to it, and an alarm tells you when it drifts. Set the alarm to the target in the contractor's plan, not a number from a blog.
The Abatement Technologies RPM-RT1 reads from -0.10 to +0.10 inWC (inches of water column), with a 3.5 inch color display and an alarm range of -0.04 to +0.04 inWC as listed. The audible alarm is rated 85 dB at 4 inches. It logs up to 12,000 events to memory and has a USB port for a flash drive. It is a wall-mount unit powered at 9 to 24 V, not straight from an outlet. For a monitor that moves from job to job in a carry case, see the Abatement Technologies PPM3-S portable differential pressure monitor ($1,400). Our room pressure monitor guide explains how differential pressure monitoring works.
Pressure log for the file
Abatement Technologies Single Room Pressure Monitor RPM-RT1
$1,210
Color-coded and audible alarms, with up to 12,000 logged events saved to memory and a USB port for a flash drive.
Step 6: Remove what cannot be cleaned
Non-porous and semi-porous surfaces like metal, glass and hard plastic can usually be cleaned. Porous material with growth, such as ceiling tiles, insulation and carpet, is normally removed and bagged. Drywall with growth is cut out past the edge of the stain. The sheeting keeps dust inside while the material comes out.
- Mist or lightly wet the surface before you scrape or cut, so dust stays down.
- Double-bag material in 6-mil polyethylene inside the containment, as the EPA guide says; seal it before it goes through the airlock.
- Keep the negative air machine running through the whole demolition.
Step 7: HEPA-vacuum, wipe and HEPA-vacuum again
The EPA recommends HEPA vacuums for final cleanup of remediation areas after materials have been thoroughly dried and contaminated materials removed, and says the filter and contents must be disposed of in well-sealed plastic bags. So HEPA-vacuum and damp-wipe now to pick up the removal dust, then make the final pass after Step 8. Scrub what is left on hard surfaces with detergent and water, then dry it completely. The EPA does not recommend a biocide such as chlorine bleach as a routine practice in mold remediation, because dead mold is still allergenic and some dead molds are potentially toxic, so the growth has to come out. If you use a disinfectant, ventilate the area and never mix chlorine bleach with cleaners that contain ammonia.
The Mosquito Carbon-Lite HEPA Backpack Vacuum is a backpack option for stairs, ceilings and tight rooms. It is listed at 152 CFM and 67 dB, draws 11.4 amps and weighs 9.8 lb in the 6-quart size or 10.8 lb in the 10-quart. The listing gives no HEPA efficiency figure, so check the maker's manual before you write a rating into a work plan. Kits start at $525. Floor and canister models are in the HEPA vacuum collection, and what a HEPA vacuum is explains sealed systems.
HEPA backpack vacuum
Mosquito Carbon-Lite HEPA Backpack Vacuum
From $525
The 6 quart suits tight rooms and stairs; the 10 quart holds more between emptyings.
Step 8: Dry the structure to normal readings
Cleaning is not the finish. The structure has to dry to the normal range for each material. A dehumidifier pulls moisture out of the air, which helps wet materials dry. Fixing the water source and getting the materials dry are what stop new growth, and the dehumidifier is one tool for the drying. It does not take out growth that is already there, as our post on whether a dehumidifier helps with mold explains. For drying rooms after a leak, dehumidifiers for water damage compares the types.
The AlorAir Storm SLGR 850X is rated by AlorAir at 85 pints per day under the AHAM test (80°F, 60% RH). Airflow is 210 CFM and it draws 5.9 A on a grounded GFCI outlet on a 15 A circuit, with a built-in condensate pump. The filter is MERV-8, and its listed coverage is up to 2,300 square feet. Weight is 63 lb, with a 12-month limited warranty. More dehumidifiers for mold jobs are in the mold dehumidifier collection, or work out the size with our dehumidifier sizing guide.
Dry the structure
AlorAir Storm SLGR 850X 85-Pint WiFi Commercial Dehumidifier with Pump
$1,099
85 pints a day at AHAM, with a built-in pump so it can run unattended into a drain.
Once the readings are back to normal, make the final HEPA-vacuum and damp-wipe pass, then call for clearance.
Step 9: Clearance before you rebuild
Clearance is the last check before drywall goes back up. The EPA describes the post-remediation checks plainly:
- The water or moisture problem has been completely fixed.
- Visible mold, mold-damaged materials and moldy odors are gone.
- If samples are taken, mold types and concentrations are similar to outdoor levels.
- A revisit shortly after remediation shows no signs of water damage or mold growth.
- People can occupy or re-occupy the space without health complaints or physical symptoms.
The same EPA page says deciding when remediation is complete is a judgment call with no easy answer. Because it is a judgment call, many owners have clearance done by an assessor who is independent of the remediation contractor. A third-party assessor, hired by the owner, sets the pass criteria before sampling and reports against them. Pass numbers come from the project plan and the assessor.
Keeping it from coming back
Clearance only holds if the water source stays fixed and the materials stay dry. Our basement mold guide covers the humidity to hold afterward.
Common mistakes
- Cleaning surfaces before the water source is fixed.
- Skipping negative air on a job that disturbs material.
- Using a regular shop vacuum without a HEPA filter on dust from the work area.
- Rebuilding on damp framing.
- Letting the crew that did the work declare the job clear.
Frequently asked questions
What steps should I take to prepare for mold remediation?
Fix the moisture source first, then measure the area and decide who does the work. Move contents out, cover vents, plan where the airlock and exhaust will go.
What is the standard for mold remediation?
ANSI/IICRC S520, the IICRC's standard for professional mold remediation, is the one professionals follow. The EPA publishes guidance on containment by area size. Neither one certifies a machine. Ask your contractor which one the contract cites.
How long will mold remediation take?
It depends on the area, how much material comes out and how long the structure needs to dry. Small jobs can finish in a day. Large contained jobs take days.
Can mold ever be fully removed?
Visible growth and damaged material can be removed, and the EPA's clearance checks describe a finished job. Mold spores are normal in outdoor air, so the aim is a normal level that holds only if the moisture source stays fixed.
What should you not do when cleaning mold?
The EPA does not recommend biocides such as bleach as routine practice, because dead mold is still allergenic. Never mix chlorine bleach with cleaners that contain ammonia. Do not run the HVAC system if you suspect it is contaminated, and do not dry-sweep or use a shop vacuum without a HEPA filter on the dust.
How long should we stay out of the area?
Follow the contractor's plan and the clearance result. We do not give a number of hours because it depends on the job and who clears it.
Can I do mold remediation myself?
Only for a small patch, about 10 square feet or less per the EPA's homeowner guide, with an N-95 respirator, gloves and goggles without ventilation holes at minimum. Larger areas need containment and trained crews. Our basement mold remediation guide shows the steps for one common case.
Equip the containment
Related guides
- Mold Remediation Equipment: The Full Kit by Job Size, From Moisture Meter to Negative Air
- Best Air Scrubber for Mold Remediation: 8 HEPA Machines Compared by CFM, Filter and Price
- Basement Mold Remediation: Steps, Equipment and the Humidity to Hold Afterward
- Does a Dehumidifier Help With Mold? What It Can and Cannot Do
