Mold Remediation Containment Barrier Setup

Why this matters

Containment is the first line of defense in mold remediation: it isolates the work area so spores released during remediation don't spread to clean areas of the building. A poorly built containment leaks spores throughout the home; the customer's occupied areas become contaminated; remediation effectively fails. A properly built containment seals the work area completely, with controlled access through a critical barrier door. The skill is in the seal: tape, sheeting, and the small details that make the difference between a barrier and a sieve.

What containment does

Containment:

• Prevents spore migration to clean areas
• Maintains negative pressure (with air scrubber inside)
• Allows safe access for workers
• Protects building occupants
• Documents work area boundaries

Containment levels per S520

Limited containment

For small projects (under 10 sq ft of moldy material):

• Minimal containment
• Drop cloth on adjacent surfaces
• Plastic sheeting around immediate work area
• HEPA-filtered vacuum during work
• No formal negative pressure required

Full containment

For typical residential remediation (10 sq ft to 100 sq ft):

• Plastic sheeting around the entire work area
• Critical barrier at access point (zipper door or two-layer)
• Negative air machine (air scrubber)
• HEPA filtration
• All workers in PPE

Full containment with negative pressure

For large or complex projects:

• All elements of full containment
• Calibrated negative pressure (typical 0.05 inch water column negative)
• Air sampling capability
• More extensive documentation

Materials and equipment

Containment materials

• 6 mil plastic sheeting (poly sheeting)
• Tyvek tape or similar high-quality construction tape
• Painter's plastic for floors (additional protection)
• Zipper doors (commercially available; ZipDoor brand etc.)
• Floor protection (Ram Board or thin plywood)

Engineering controls

• Negative air machine / air scrubber (with HEPA filter)
• Auxiliary HEPA vacuum
• Temperature and humidity meter
• Manometer (for pressure verification)
• Air sampling equipment (for verification)

Pre-containment preparation

Step 1: Clear the work area

• Remove furniture, art, valuables (if possible)
• Cover anything that can't be moved with plastic
• Document existing condition

Step 2: Plan the containment

• Identify the containment perimeter
• Note doors, windows, HVAC vents in the area
• Plan air scrubber location
• Plan access point (critical barrier)

Step 3: Address HVAC

• Shut off HVAC serving the contained area
• Seal HVAC vents within containment
• This prevents spore distribution through ductwork

Containment installation

Step 1: Floor protection

• Lay floor protection (Ram Board) over the original floor in the work area
• Tape seams
• Protects original floor; provides clean working surface

Step 2: Wall and ceiling protection

If walls and ceiling will be exposed to work:

• Cover with poly sheeting
• Tape edges
• Protects from contamination during work

Step 3: Containment perimeter

The actual barrier:

• 6 mil poly sheeting
• Floor to ceiling
• All sides of the work area
• Tape all seams (Tyvek tape; multiple passes)

For each side:

• Adhere to ceiling first
• Drop down to floor
• Tape to baseboards or floor
• Vertical seams sealed

Step 4: Critical barrier at access

Standard methods:

Zipper door

• Commercial zipper door panel
• Tape to existing wall material on each side
• Provides controlled access
• Reusable

Two-layer flap

• First layer: poly sheeting with a vertical slit
• Second layer: poly sheeting with horizontal slit
• Two layers offset so spores don't directly escape

Standard door

• Existing door
• Sealed with tape and poly around the frame
• Open with appropriate PPE

Step 5: Verify all seals

• Walk the perimeter; verify all seams sealed
• Check for any gaps or pinholes
• Address with additional tape
• Check HVAC vent seals

Step 6: Install negative pressure

• Place air scrubber inside containment
• HEPA filter on intake
• Exhaust through wall, window, or door (to outside if possible)
• Verify discharge doesn't recirculate to home

The air scrubber:

• Pulls air through HEPA filter
• Maintains negative pressure inside containment
• Captures spores in the filter
• Discharges clean air

Step 7: Verify negative pressure

• Use manometer at the critical barrier
• Verify pressure is negative (typically -0.02 to -0.05 inch water column)
• If positive, adjust air scrubber or check for leaks

Specific containment scenarios

Single-room containment

• Containment around the room perimeter
• Critical barrier at the door
• HVAC vents within the room sealed
• Air scrubber inside

Partial-room containment

• Plastic perimeter around just the contaminated area
• Smaller air scrubber
• Limited containment if appropriate

Whole-floor containment

• Containment at the stair landing
• HVAC zones isolated
• Multiple air scrubbers if needed

Crawl space or attic

• Crawl space: sealed entry and access points; HEPA vacuum during work
• Attic: ceiling penetrations sealed; access through attic stairs

Air scrubber sizing

The air scrubber must provide adequate air changes per hour:

For high-rate air exchange (4 to 6 air changes per hour):

• Volume in cubic ft × 4 / 60 = CFM needed for 4 air changes

A typical 12 x 12 x 8 = 1,152 cubic ft room needs roughly 76 CFM for 4 changes per hour, but most air scrubbers run 500 to 2,000 CFM for adequate clearance.

Negative pressure maintenance

Negative pressure (typically -0.02 to -0.05 inches water column):

• Measure with manometer
• If too low (closer to positive): air leaks; check seals
• If too high (very negative): may pull contaminated air from other areas
• Adjust air scrubber speed

Common containment errors

Inadequate seal at edges

• Spores escape
• Tape with multiple layers
• Use sealant for critical seals

HVAC vent not sealed

• Spores distributed through ductwork to clean areas
• Verify all vents are sealed

Air scrubber too small

• Inadequate air exchange
• Negative pressure not maintained
• Worker discomfort during work

Plastic sheeting torn or damaged

• Spores escape through tears
• Inspect daily; repair any damage

Critical barrier left open

• Workers entering and exiting through unprotected gap
• Spores escape
• Train workers; use zipper door for ease

Containment removed too early

• Spores still suspended in air after work
• Allow air scrubber to run after work completion
• Test air before removing containment

Post-work containment removal

Sequence

Containment comes down last, in order, and only after the work inside it is finished and verified. Taking it down early or out of order undoes the whole job.

1. Finish the work and the detail cleaning inside containment. All removal complete, all debris bagged and out, all surfaces HEPA-vacuumed and damp-wiped. The containment stays up through the final cleaning, not just through demolition.
2. Run the air scrubber on the sealed space. Keep negative pressure and keep the unit running after cleaning so airborne particulate is pulled down. Do not open the barrier during this period.
3. Get clearance before anything comes down. Where post-remediation verification applies, the visual inspection and any air sampling happen with containment still intact and the scrubber still running. A failed clearance after the barrier is down means rebuilding containment from scratch.
4. Take down the interior sheeting first, working from clean to dirty. Mist or HEPA-vacuum surfaces before pulling. Roll or fold each sheet inward on itself so the contaminated face ends up inside the roll, never shaken out into the room.
5. Bag as you go. Sheeting, tape, filters, and disposable PPE go into disposal bags inside the containment, sealed there, and the outside of each bag wiped before it leaves.
6. Remove the critical barrier last. It is the final line between the work area and the occupied space, so it comes down after everything behind it is bagged and gone.
7. Shut the scrubber down last, and change its filters. A loaded HEPA filter is contaminated material; handle and bag it accordingly. Wipe the unit's housing before it goes back on the truck.
8. Clean the transition zone and the egress route. HEPA-vacuum and wipe the floor from the work area out to the exit, including anywhere a bag was carried or set down.
9. Restore HVAC. Unseal the vents, replace any system filter that ran during the project, and confirm the system operates normally before the occupants return.
10. Walk the space with the customer and document the finished condition with photographs.

If clearance fails at any point in this sequence, stop. Re-establish containment, re-clean, and re-test. Do not negotiate a partial release.

References

• IICRC S520 (Standard for Professional Mold Remediation).
• IICRC AMRT certification material.
• EPA mold remediation guidance.
• OSHA general duty requirements.
• Manuall internal: Mold Remediation IICRC S520 Standards Summary.