From Dog Food Plants to Float Tanks: Unusual Moisture Intrusion Cases Explained

Many moisture claims start a similar way: “We’ve got water where it shouldn’t be. Must be the roof.” Sometimes it is. Often, it isn’t. Water has more than one way to become a problem in a building. In addition to wind-driven rain and plumbing leaks, I’m frequently called to losses where the culprit is invisible: water vapor that condensed into liquid because temperature and humidity crossed a line we call the dew point.

Two of my more memorable cases were nowhere near “typical”—a dog-food meat processing plant and a wellness facility with sensory-deprivation float tanks. Different occupancies, opposite thermal conditions, identical mechanism: warm, moist air reached a cold surface, condensed, and quietly damaged the structure out of sight.

Below is how I approach these kinds of assignments, what I look for, how I separate cause from scope, and the practical fixes that prevent a repeat.

Case 1: The chilled cutting room with a hot attic

The incident: Ceiling panels in a refrigerated meat-cutting room kept loosening and falling. Staff would re-fasten panels, only to have them pull away again.

What I found: The space above the cutting room—an attic/void—was hot. The cutting room below was kept cold. Where those environments met, unprotected components became a condensing surface. Warm attic air repeatedly hit the cold top side of the ceiling assembly, water vapor turned to liquid, and the resulting moisture rotted the wood framing. Workers were trying to fasten panels into members that no longer had any holding capacity.

The failure chain, in plain terms:

• Hot, humid air in the attic →
• Contacts cold surfaces at the refrigerated envelope →
• Reaches dew point →
• Liquid water accumulates →
• Wood decays and fasteners lose purchase →
• Panels fall; the symptom hides a larger structural problem.

What mattered diagnostically: I traced the problem backward from the symptom (loose panels) to the root (uncontrolled vapor and missing/incorrectly located barriers). The condition was not a “roof leak,” and patching the interior would never last. The fix required re-establishing the thermal and vapor boundary: correct membrane placement, sealed transitions, and separating the hot air from the cold envelope so surfaces don’t sit at dew-point conditions.

Case 2: The warm float-tank suites with a cold attic

The incident: Persistent “roof leaks” over private float-tank rooms despite roofing repairs and roofer sign-offs.

What I found: The float rooms were warm and humid by design; they generate moisture. During cold weather, the attic above was cold—exactly the reverse of the meat plant. Moist interior air migrated upward, reached cold surfaces in or above the ceiling, condensed, and dripped back down into the rooms. Roofing contractors had done their job; the roof was tight. The problem was internal vapor, not external water.

The failure chain, reversed scenario:

• Warm, moisture-laden interior air →
• Moves upward into/through the ceiling →
• Meets cold surfaces in winter →
• Reaches dew point →
• Condensate forms and returns as “leaks.”

What mattered diagnostically: Field observations aligned with the seasonality: complaints spiked in winter. I looked for telltale markers of condensation (clean water, recurring in cold snaps, staining patterns at penetrations and thermal bridges) versus the signature of a roofing defect (wetting after rain regardless of temperature, consistent tracer paths from exterior). Again, the remedy lived inside the envelope: vapor control, air sealing, localized dehumidification/exhaust, and details that keep warm, moist air from ever touching cold materials.

The common thread: Dew point, not downpours

These two cases sit on opposite ends of the thermal spectrum, but the physics are the same. You don’t need a roof hole to have “water damage.” You just need:

• Moist air (from process loads, occupancy, or ambient conditions),
• A cold enough surface (created by refrigeration, winter conditions, or thermal bridges), and
• A pathway (air leaks, gaps at penetrations, missing or mis-placed vapor/air barriers).

When those three align, vapor becomes liquid and stays put. Given time, that quiet wetting is as destructive as any storm.

How I separate cause from scope

When I’m retained on a moisture intrusion file—especially one with “mystery leaks”—I break the work into two questions:

1. What caused it?
2. How far did it go?

1) Causation: proving condensation versus “roof leak”

I start with building use and the microclimate on each side of the envelope. I’m looking for temperature differentials, vapor sources, and pathways. In the field, the indicators that point to condensation rather than an exterior breach include:

• Seasonality and operating conditions: Problems that correlate with cold snaps (or refrigeration cycles), not rain events.
• Location patterns: Wetting clustered at penetrations, ducts, steel framing, or edges—classic thermal bridge and air-leak sites.
• Water characteristics: Clean drip lines and mineral tracks without the debris that often rides in with rainwater.
• Envelope detailing: Absent/mis-located vapor barriers, unsealed transitions, or membranes placed on the wrong side of the assembly for the climate and use.

Once the mechanism is clear, we can stop chasing the roof and start fixing the physics.

2) Scope: finding the full extent, not just the symptom

Condensation rarely damages only the visible finish. In both the meat plant and float facility, the real loss was in concealed spaces. I document:

• Framing condition: Probe tests at suspect members, especially where fasteners have failed or where stained paths lead into cavities.
• Connection integrity: Rust at hangers/fasteners, loss of withdrawal or shear capacity in wood, and deterioration at panel joints.
• Adjacent cavities and finishes: Moisture migration across bays, behind vapor-open finishes, and into insulation that no longer dries.

The end product is a repair scope that addresses what failed (materials and connections), why it failed (vapor/air/thermal control), and the measures needed to prevent recurrence.

Practical fixes I tend to recommend

Every building is unique, but these measures come up often in condensation-driven losses:

• Put the boundaries in the right place. In cold-side risk scenarios (float rooms in winter), move or add the vapor retarder to the warm, moisture side of the assembly; in cold-envelope scenarios (refrigerated rooms), ensure the cold boundary is continuous and sealed from warm attic air.
• Eliminate pathways. Seal penetrations, top plates, and transitions. Air leakage is the express lane for moisture.
• Control the source. Provide exhaust and/or dehumidification in high-moisture rooms; manage process loads above spaces with cold surfaces.
• Tackle thermal bridges. Insulate or isolate steel members and other conductive paths so they don’t become unintended condensing surfaces.
• Design for drying. Where feasible, choose materials and details that allow incidental moisture to escape rather than remain trapped.

Why this matters to insurers and owners

Condensation losses can masquerade as roof failures. That misdiagnosis leads to cycles of ineffective repair—new membranes, more patching—while the real issue worsens out of sight. A targeted forensic assessment does three things:

• Clarifies coverage questions by distinguishing weather-driven water from long-term vapor behavior.
• Prevents scope creep by mapping damage beyond the visible symptoms.
• Reduces recurrence by tying repairs to building physics, not just finishes.

In the meat plant, re-fastening panels would have remained a maintenance headache until the ceiling structure fully failed. In the float facility, roofing work couldn’t solve a winter-only “leak.” In both, the durable answer was restoring a continuous, well-detailed thermal and vapor boundary.

Closing thought

Moisture intrusion isn’t always about storms and shingles. Sometimes the problem is the air inside the building meeting the wrong surface at the wrong temperature. If you’re facing a “leak” that doesn’t line up with rain—or a symptom that keeps returning after repairs—there’s a good chance dew point is somewhere in the story. That’s a forensic problem we can solve.

About the Author

Nels R. Peterson, P.E., M.S.C.E. is a Consulting Engineer in our Seattle-Tacoma Office. Mr. Peterson provides consultation in the areas of structural analysis, scope of damage, cause of damage, and water intrusion investigation. You may contact Nels for your forensic engineering needs at npeterson@edtengineers.com or (253) 345-5187.

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