Most water damage events look dry long before the structural assemblies actually are. A room that smells fine and feels dry to the touch may have framing at 25-30% moisture content — well above the 6-12% target range required for true structural drying. COS Water Damage Restoration's Larsen structural drying program is driven by daily psychrometric readings, not visual judgment.
The difference between structural drying done right and structural drying done fast is what ends up in your walls three months later.
Low-grain refrigerant (LGR) dehumidifiers operate more efficiently in the low-humidity conditions created by an active drying program than conventional dehumidifiers — achieving lower dewpoint conditions that accelerate evaporation from structural materials. Our Larsen structural drying crews deploy properly sized LGR equipment based on the specific volume and material profile of your affected assemblies. Equipment sizing is calculated, not estimated.
Documented daily readings are what separate a professional drying program from a rental dehumidifier in the corner.
Wall cavity drying is where most post-loss mold in Larsen properties originates. It's where we focus.
COS Water Damage Restoration's Larsen drying technicians generate moisture logs formatted specifically for insurance claim submission — daily readings at sensor point locations mapped to a floor plan, equipment placement and settings recorded, and final confirmation readings that document the completion of the drying program. Xactimate-compatible line items for each day's equipment and labor make the drying scope transparent to your adjuster and minimize the chance of a supplement dispute on the drying phase of your claim.
Here are the specific drying scenarios and assembly types our Larsen team is equipped and trained to handle.
The most common drying failure in Larsen water damage projects is a wall framing cavity left with elevated moisture content after surface materials are dry. Our Larsen team uses calibrated cavity access — typically 1-inch drill holes at the base of the wall framing cavity — to introduce directed airflow from high-velocity air movers into the stud bay, paired with LGR dehumidification to extract the evaporated moisture. Moisture readings at framing sensor points confirm completion. Access ports are patched and filled after the program completes, typically leaving no visible trace of the access procedure.
Subfloor and hardwood drying in Larsen is species-specific and requires daily monitoring of cupping and moisture gradient.
Crawlspace saturation after a water event in Larsen often goes undetected — we include it in every below-grade moisture mapping session.
Water that migrates down from an upper floor or a roof intrusion in a Larsen property saturates ceiling drywall and the framing above it — areas that are impossible to reach with standard floor-level equipment. Our Larsen team installs ceiling injection ports and directs positive-pressure airflow through ceiling cavities, combined with LGR dehumidification of the affected room air space. Ceiling drywall that cannot be dried to target moisture content is removed — rather than left to become a mold substrate — and documented in the scope for replacement.
Large-scale commercial drying in Larsen is project-managed from day one with zone-specific reading logs.
Mold prevention is not a separate service — it's built into every Larsen structural drying program we run.


Equipment before mapping is guesswork. Mapping before equipment is science.
Equipment placement is engineered based on the moisture map and assembly data — not placed by habit.
Every calendar day, our Larsen technician visits your property, takes complete psychrometric readings at all sensor points and ambient measurement locations, logs the data, adjusts equipment if indicated, and reports the daily progress to you and your insurance carrier. The drying program continues until all assemblies reach their EMC target range.
Completion is confirmed by instruments and documented in writing. No visual estimates.



"We'd had a water damage company dry our house after a previous event and they removed equipment on day 5 and called it done. Three months later, mold behind the walls. This time I specifically chose COS Water Damage Restoration because of their documentation process. Daily readings, specific sensor point data, instrument-confirmed completion. No mold, no callbacks, no repeat of the last time."
"The thermal imaging session at the beginning was what showed us the water had migrated into a wall cavity adjacent to the flooded room that we never would have found otherwise. COS Water Damage Restoration set up wall cavity drying for that section specifically, and the final readings confirmed it came out completely dry alongside everything else. That's the kind of detail that prevents the mold problem three months later."
"We manage several Larsen commercial properties and structural drying after water events is something we deal with periodically. COS Water Damage Restoration is the only company we use because of their documentation process. Zone-specific readings, daily logs we can review from our office, and a written drying completion report at the end of every project. When a tenant asks for proof that remediation was complete, we have an instrument-confirmed document, not a technician's verbal assurance."
COS Water Damage Restoration's Larsen structural drying team serves Larsen and surrounding communities throughout WI. Daily monitoring included. Call +1-844-499-0972 to get started.
Don't let wet wall cavities become next month's mold problem. Call +1-844-499-0972 and get Larsen's certified structural drying team on site.
📞 Call +1-844-499-0972 — Larsen Structural Drying24/7 Available · IICRC WRT Certified · Daily Readings · Larsen, WI