Crawl Space Mold Remediation — Clearfield, UT

Loss Type: Mold Remediation / Crawl Space Moisture and Mold Growth
Location: Clearfield, UT near 200 West
Response Time: Next-day scheduled
Job Duration: 2 days on-site plus 48-hour monitoring
Insurance: No – homeowner self-pay

The Situation

A homeowner near 200 West in Clearfield contacted us after noticing a persistent musty smell in their home that was strongest near the floor vents in the living room. An HVAC technician who had been called for an unrelated issue suggested they have a professional mold inspection done before assuming the smell was duct-related. Our mold remediation team revealed significant mold growth across the floor joists and subfloor decking in the crawl space — the source of the odor being drawn into the home through the HVAC system.

The Problem

The crawl space had two contributing moisture sources working together. First, the existing vapor barrier was a thin 6-mil sheet that had torn in multiple locations and had never been sealed to the foundation walls — allowing ground moisture to evaporate freely into the crawl space air. Second, two of the foundation vents on the south side of the home had become partially blocked by soil settlement, reducing cross-ventilation and allowing humidity to accumulate.

The combination of crawl space moisture and poor ventilation had elevated the crawl space relative humidity high enough to sustain active mold growth across approximately 340 square feet of joist and subfloor surface. The growth was heaviest in the center of the crawl space where airflow was lowest. Moisture readings on the joists confirmed elevated levels consistent with chronic high-humidity exposure.

Because the HVAC return air was pulling from the floor space above the crawl space, mold spores had been entering the home’s air distribution system — explaining the musty odor throughout the house.

What We Did

We established containment at the crawl space access hatch and ran a HEPA air scrubber throughout the remediation. Per IICRC S520 crawl space mold remediation protocol the scope included:

• HEPA vacuuming of all affected joist and subfloor surfaces
• Wire brushing of all mold-affected wood surfaces to remove surface growth
• Application of EPA-registered antimicrobial solution to all affected framing
• Application of EPA-registered encapsulant to all treated surfaces after drying
• Removal and disposal of the torn existing vapor barrier
• Installation of new 20-mil reinforced vapor barrier sealed at all seams and lapped up foundation walls
• Clearing and resealing of the two blocked south-side foundation vents
• Placement of a commercial dehumidifier to bring relative humidity to target range

We also documented the HVAC duct condition in our report and recommended the homeowner have the duct system professionally cleaned given the confirmed spore presence in the air supply — a separate item outside our scope that we flagged for their awareness.

Post-remediation air sampling was performed by an independent industrial hygienist 48 hours after completion.

The Outcome

Clearance sampling confirmed spore counts within acceptable outdoor baseline levels. The musty odor in the home resolved within several days of the crawl space remediation as the contaminated air was cycled out. The homeowner arranged for duct cleaning separately. The new vapor barrier and restored ventilation eliminated the moisture source conditions that had caused the growth.

“We had that smell for almost a year and kept thinking it was something else. Upkeep found mold all over the crawl space in about 20 minutes. They fixed it properly, tested it, and the smell was gone within a few days. Wish we had called sooner.”

— K. and T. Olsen, Clearfield UT

Related Case Studies

We’ve handled a range of moisture and water damage events in Clearfield, including a sump pump failure in Clearfield that led to similar crawl space humidity issues. We’ve also documented a crawl space moisture intrusion in Layton with comparable vapor barrier and ventilation failures. View more of our case studies from Davis County homeowners.