[Case Study] Clearing Widespread Mold From an 85,000-Sq-Ft Warehouse—Without Shutting It Down

A Commercial Mold Remediation Case Study: MK2 Properties LLC, Ashtabula, Ohio

Pine Ridge Restoration completed a large-scale commercial mold remediation project for MK2 Properties LLC at an 85,000-square-foot commercial warehouse in Ashtabula, Ohio. The facility had building-wide Aspergillus/Penicillium contamination confirmed by independent laboratory testing. Rather than relying on a standard room-by-room containment approach, Pine Ridge Restoration used engineered whole-building airflow management to complete the work efficiently while supporting the client’s operational needs.

• Client: MK2 Properties LLC
• Facility: 85,000 sq. ft. commercial warehouse in Ashtabula, Ohio
• Problem: Building-wide Aspergillus/Penicillium contamination confirmed by independent lab testing
• Approach: Engineered whole-building airflow management without standard poly containment
• Standards followed: ANSI/IICRC S520, ANSI/IICRC S500, and OSHA requirements
• Independent lab: EMSL Analytical
• Result: 97–98%+ reduction in airborne mold at every tested location, verified by an independent lab
• Timeline: Inspection on March 16, 2026; mobilization on May 26, 2026; completion on July 1, 2026

The Challenge

MK2 Properties LLC owns an 85,000-square-foot commercial warehouse in Ashtabula, Ohio. The building is a single, contiguous industrial space with CMU walls, exposed structural steel, open-web steel joists, and a metal pan ceiling. During a facility assessment, visible discoloration consistent with microbial growth was found across the exposed structural steel, ceiling pans, and joist assemblies.

Visible mold is only part of the picture in a building of this size. Before committing to a remediation strategy, Pine Ridge Restoration needed to determine whether the contamination was confined to isolated areas or spreading through the building’s air. The team brought in EMSL Analytical, an independent accredited laboratory, to test the facility before work began.

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What the Lab Found

On May 26, 2026, Pine Ridge Restoration collected calibrated air samples using a Zefon Z-Lite IAQ pump, Air-O-Cell media, and a sampling rate of 15 L/min for 5 minutes. Samples were taken from five locations: an outdoor reference point, the northwest warehouse, the southeast warehouse, the women’s restroom, and the upstairs cafeteria. All samples were submitted under chain-of-custody to EMSL Analytical for independent analysis.

Three of the four interior locations tested at or above the outdoor reference. The upstairs cafeteria, an occupied support space, tested at nearly double the outdoor reference. Because the pattern appeared across widely separated areas instead of clustering in one room, the results pointed to a building-wide issue rather than a single leak or isolated trouble spot.

Why a Standard Containment Plan Was Not the Right Fit

The standard residential mold remediation approach often relies on sealed poly containment around a specific work area. In an 85,000-square-foot warehouse operating as one open volume, that approach would have provided limited engineering benefit while significantly slowing the job. The client also needed the facility returned to operation as efficiently as possible.

Instead, Pine Ridge Restoration’s team, led by IICRC Triple Master Certified Restorer Richard McGuigan, designed a whole-building push-pull airflow strategy built around the size and geometry of the facility.

The strategy included:

• Approximately 30,000–40,000 CFM of controlled exhaust airflow established with high-capacity axial air movers.
• Phoenix Guardian-R HEPA air scrubbers supplying continuously filtered make-up air.
• A directional airflow pattern engineered to reduce particulate residence time and prevent uncontrolled recirculation during active cleaning.

The strategy followed the intent of ANSI/IICRC S520, the industry standard for professional mold remediation, as well as ANSI/IICRC S500 and applicable OSHA requirements. Pine Ridge Restoration applied engineering judgment to the building’s specific conditions rather than forcing a one-size-fits-all containment model onto a space it was not designed for.

“Conventional room-by-room containment wasn’t practical in a warehouse this size. We engineered airflow the way you’d engineer HVAC for a building—moving contaminated air out and clean, filtered air in, continuously, everywhere at once.”

— Richard McGuigan, IICRC Triple Master Certified Restorer

The Work: Source Removal, Controlled Drying, and Independent Proof

With engineering controls established, crews mobilized on May 26, 2026 and completed the project on July 1, 2026. A project-specific Health and Safety Program addressed elevated work at heights approaching 24 feet, chemical exposure, and slip hazards from wet cleaning. Crews worked in full-face respirators, protective suits, and hearing protection, with daily tailgate meetings to review sequencing and conditions.

The Remediation Sequence

• HEPA vacuuming of all accessible structural components.
• High-velocity air washing to dislodge accumulated particulate from steel members and joists.
• PHire cleaning solution, boosted with CitruSolv where needed, followed by pressure washing of affected structural surfaces.
• Continuous truck-mounted extraction to recover wash water and limit secondary wetting.
• Mechanical floor scrubbing with a ride-on propane scrubber following overhead cleaning.
• Commercial dehumidification to accelerate drying and stabilize humidity for roughly one week.
• Final application of ProKlean L antimicrobial, EPA Reg. No. 87508-3-104210, per label.

Mechanical source removal, not chemistry, was the primary objective throughout the project. Cleaning products supported the physical work rather than replacing it. Supervisory personnel evaluated cleaning effectiveness and equipment performance throughout production, not only at the final walkthrough. Corrective cleaning was required before crews moved to the next phase.

The Results, Verified by an Independent Lab

After remediation and drying stabilized, Pine Ridge Restoration collected a second full round of chain-of-custody air samples from the same five locations and submitted them to EMSL Analytical for independent verification.

The upstairs cafeteria provided one of the clearest before-and-after comparisons. It began as the building’s worst reading, at roughly 1.8 times the outdoor level, and finished at more than 98% below outdoor air after remediation. Every interior location moved from at or above the outdoor reference to well below it.

The verification samples also showed no detected Chaetomium, Fusarium, Stachybotrys, or hyphal fragments, which are indicators of active water-damage-related mold growth.

Pine Ridge Restoration evaluated the outcome against multiple lines of evidence, including completion of the specified cleaning protocol, visual cleanliness, moisture stabilization, ongoing quality-control inspections, and independent laboratory findings. Together, those factors supported a clear determination that the contracted remediation scope was successfully completed.

“The cafeteria had the worst numbers going in, so it’s the best proof the plan worked. When your worst room comes back cleaner than the outdoor air, that’s not luck—that’s the airflow design and the cleaning sequence doing exactly what they were built to do.”

— Richard McGuigan, IICRC Triple Master Certified Restorer

Keeping the Building Protected After Remediation

Pine Ridge Restoration’s closeout report gave MK2 Properties clear, practical maintenance guidance. The recommendations included promptly correcting any future roof leaks, plumbing failures, or other moisture intrusion; keeping indoor humidity in an appropriate range for the occupancy; maintaining routine housekeeping on elevated structural components; and inspecting the roof and building envelope periodically.

A successful remediation is not a permanent guarantee against future growth. It creates a clean baseline that proper building maintenance can help protect.

Commercial Mold Remediation: Frequently Asked Questions

How do you verify that commercial mold remediation actually worked?

Pine Ridge Restoration relies on multiple lines of evidence rather than a single test. These include completion of the specified cleaning protocol, visual cleanliness, documented moisture stabilization, ongoing quality-control inspections during the work, and independent post-remediation air sampling analyzed by a third-party laboratory. On this project, EMSL Analytical performed the independent laboratory analysis.

There is no single federal numerical pass/fail threshold for airborne mold. Results are compared against a same-day outdoor reference sample and evaluated for abnormal indicator organisms.

Why not use standard poly containment for a large warehouse mold job?

Sealed room-by-room poly containment is designed for smaller, compartmentalized spaces. In a large, open industrial building operating as one contiguous volume, it provides limited engineering benefit while significantly slowing production. Pine Ridge Restoration instead engineered whole-building airflow management using high-capacity exhaust paired with HEPA-filtered make-up air to control contaminant transport across the entire facility.

What standards govern professional mold remediation?

Pine Ridge Restoration performs commercial and residential mold remediation consistent with the intent of ANSI/IICRC S520, the industry standard for professional mold remediation, and ANSI/IICRC S500, the standard for professional water damage restoration. The team also follows applicable OSHA worker-safety requirements.

How long does mold remediation take for a large commercial building?

Timelines depend on square footage, contamination extent, and building geometry. On this 85,000-square-foot warehouse project, active remediation ran roughly five weeks, from mobilization to laboratory-verified completion, following an initial assessment and pre-remediation lab testing.

What credentials should a commercial mold remediation contractor have?

Look for IICRC certification and, ideally, a team led by an IICRC Master Certified Restorer. This project was led by Pine Ridge Restoration’s Richard McGuigan, who holds IICRC Triple Master Restorer status. Property owners should also ask whether pre- and post-remediation testing is performed by an independent, accredited laboratory rather than the remediation company itself.

About Pine Ridge Restoration

Pine Ridge Restoration, Inc. provides commercial and residential water, fire, construction, and mold restoration services. The company applies engineering-driven remediation strategies and independent laboratory verification to projects ranging from single-room water losses to large-scale commercial mold remediation projects like the MK2 Properties warehouse case study.

This project was led by Richard McGuigan, an IICRC Triple Master Certified Restorer. The IICRC Master designation is held by a small percentage of restoration professionals nationwide and requires advanced certification across multiple restoration disciplines.

Facing mold, water, or fire damage in a commercial or residential property? Contact Pine Ridge Restoration to schedule an assessment.