If you have handled water losses located in California or along the coast you may have run across shear walls. Shear walls are basically required by building codes in some areas due to potential high winds from hurricanes or seismic activity from earthquakes. They are designed to transfer horizontal forces to other load-bearing walls or to the foundation. This can be accomplished by adding an OSB or plywood panel to the wood framing of exterior and sometimes interior walls. This assures the wall remains rigid even under lateral pressure.

Shear walls can impact a residential drying project when trying to dry the OSB or plywood shear wall behind the drywall. It may require opening the bottom of the wet drywall to get hot, dry air to the wet OSB or plywood behind it. Check with the local restorer for they should be familiar with dealing with shear walls in their areas and what the local building code mandates when potentially needing to open or drill holes to get hot, dry air into the wall assembly. If drying the shear wall and drywall in-place it would qualify for a class 4 situation due to drying multiple layers and may need to heat up the wet surface between 95-100 degrees F to speed up the evaporation process. Ask for photos of drying setup, including any containment and IR thermometer and moisture content readings.