What is a sign that a subfloor has not been properly dried before reinstallation?

Persistent odors and visible mold are strong indicators that a subfloor has not been properly dried before reinstallation. When moisture remains trapped within the subfloor, it creates an environment conducive to mold growth, which typically manifests with musty or sour odors. Mold thrives in damp conditions, and its presence signals that the underlying material has not reached an acceptable moisture content for safe installation of new flooring.

In contrast, perfect alignment of flooring seams, even texture across all surfaces, and a quick timeline to complete the job are not definitive indicators of proper drying. Perfect seam alignment and even texture are more related to the skill of the installer and the type of flooring material used, rather than the moisture conditions of the subfloor. A quick job timeline can sometimes lead to the neglect of essential steps like thorough drying and moisture assessment, but it does not inherently reflect the quality of the drying process itself. Therefore, persistent odors and visible mold serve as a clear warning sign that the drying process was inadequate.