Mold Growth
As a direct cause of mold, the use of wall covering on the exterior walls of a building does not pass the “but for” test; only water does. Without the accumulation of water within a wall, mold will not occur. Water within the exterior wall construction can come from three sources:
- Residual moisture, i.e., wetting of the interior components prior to the completion of the building.
- Water, i.e., leakage, past the water-resistive barrier, into the interior components following completion.
- Condensation of water vapor that diffused through the wall construction, which itself is related to the temperature of the interior environment, and particularly the interior wall surface.
Often rain during the construction of a building causes wetting of the materials that will be closed-in within the water barrier; those wet materials may not dry out completely, or may not be completely removed, prior to the installation of the interior finishes. Moisture left over from construction closed up within a building envelope is residual moisture. Sometimes a contractor will begin the installation of interior finishes, presumably in the interest of time, without the HVAC systems having first been placed in operation to condition the space.
