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

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.