Contain Contaminated Areas

Introduction

Once mold is discovered, proper containment is essential to prevent the spread of spores to unaffected areas. Mold spores are microscopic and easily airborne, settling on furniture, clothing, and HVAC systems, creating secondary contamination.

By setting up physical barriers, you can control the spread of airborne mold spores and protect clean areas while working on remediation.

This lesson covers:

  • How to set up containment barriers for ceilings, walls, and floors
  • How to properly seal cabinets and built-in fixtures
  • General containment techniques for rooms and large spaces
  • Simple containment options for small mold areas

By following these steps, you can reduce cross-contamination, limit health risks, and make mold remediation more effective.

Why Containment is Crucial for Mold Control

Without containment, mold spores spread freely, making cleanup more difficult and costly.

Risks of Uncontained Mold

  • Mold spores travel through the air, contaminating unaffected rooms.
  • HVAC systems pull in spores and spread them throughout the home.
  • Spores settle on clothing, furniture, and personal belongings, requiring additional cleaning.
  • Mold remediation efforts become ineffective without proper containment.

💡 Fact: A single mold colony can release thousands of spores per second, making quick containment essential.

General Containment for Rooms and Large Areas

If mold contamination is suspected in a room or large area, setting up full-room containment is the best approach.

Materials Needed

  • 6-mil plastic sheeting (thick plastic barrier to seal off the space).
  • Duct tape or 3-inch painter’s tape (for securing plastic sheeting).
  • Zippered containment door (for controlled access).
  • HEPA air scrubber or air purifier (optional but recommended).

Step-by-Step Room Containment

1️⃣ Seal Off the Room

• Hang plastic sheeting from floor to ceiling to create a sealed environment.

• Secure sheeting over doorways, vents, and openings using duct tape or wide 3-inch painter’s tape for a stronger seal.

• Install a zipper containment door for controlled entry and exit.

2️⃣ Turn Off Airflow

• Shut down HVAC systems and fans to prevent spores from circulating.

• If the HVAC must stay on, cover vents with small HEPA-rated filters.

3️⃣ Use Negative Air Pressure (If Possible)

• Position a HEPA air scrubber or exhaust fan to vent air outside the home.

• This creates negative air pressure, pulling spores out instead of allowing them to settle inside.

💡 Tip: For severe contamination, consider double-layering containment barriers to create a buffer zone before entering the affected area.

Surface Containment for Ceilings, Walls, and Floors

Why It’s Important

Mold can grow on drywall, ceiling tiles, wood, and flooring materials. When disturbed, mold releases spores into the air, contaminating other surfaces.

Temporary surface containment helps prevent the spread of dust, spores, and debris during remediation.

How to Contain Ceilings

  • Cover the affected ceiling area with 6-mil plastic sheeting.
  • Secure edges with 3-inch painter’s tape to prevent air leaks.
  • If cutting into the ceiling, mist with water first to reduce dust and spore release.
  • Use a plastic drop cloth to catch debris below.

How to Contain Mold on Walls

  • Seal plastic sheeting over the entire wall if mold is suspected inside.
  • Use double-sided tape or adhesive strips to attach plastic securely.
  • Do not remove drywall until containment is fully set up.

Floor Containment

  • Lay plastic sheeting over carpets and hard flooring.
  • Secure with duct tape along baseboards.
  • If removing contaminated flooring, use an additional layer of plastic sheeting to trap debris.

💡 Tip: If extensive remediation is needed, creating a decontamination zone outside the contained area prevents spores from spreading when leaving the space.

Containing Cabinets and Built-in Fixtures

Why Cabinets Need Special Containment

Mold can grow inside and behind cabinets, especially if water damage has occurred. Removing cabinets without proper containment can release large amounts of spores.

Steps for Proper Cabinet Containment

  • Seal the cabinet doors shut using 3-inch painter’s tape to create a strong, wide seal.
  • If removal is necessary, set up plastic containment around the cabinet before detaching it.
  • Use a HEPA vacuum inside cabinets before opening them to remove loose spores.
  • If cabinets must be disposed ofwrap them in plastic sheeting before carrying them out.

💡 Tip: Always check behind cabinets—mold can grow unnoticed in wall cavities and spread behind built-ins.

Simple Containment for Small Areas of Mold

If only a small area (less than 10 square feet) is contaminated, full-room containment may not be necessary. Instead, a quick containment method can be used:

Tape Containment Method for Small Areas

  • Cover the visible mold directly with overlapping strips of tape (3-inch painter’s tape is ideal for this).
  • Ensure all edges are fully covered, overlapping layers to prevent gaps.
  • Do not remove or disturb the mold until proper remediation steps are in place.

💡 Tip: This method is effective for preventing airborne spore release while waiting for full remediation.

Maintaining Containment During Remediation

Once containment is set up, it must remain intact until remediation is complete.

Common Mistakes to Avoid

❌ Tearing plastic sheeting when moving equipment in and out.

❌ Forgetting to reseal doorways and vents after inspections.

❌ Stepping in and out of the area without decontaminating clothing.

❌ Not replacing plastic barriers when damaged.

How to Prevent Containment Failures

  • Regularly check for leaks or gaps in containment barriers.
  • Use separate protective gear inside and outside the contained area.
  • Dispose of contaminated materials carefully, sealing them in plastic bags before removal.

💡 Tip: If you smell mold outside the contained area, spores are escaping—check for leaks immediately.

Conclusion

Setting up effective containment barriers is one of the most important steps in mold remediation. By sealing rooms, surfaces, and built-in fixtures properly, you can prevent the spread of mold spores and make cleanup more manageable.