However, the most common problem I find, involves crawl space covers that are inappropriate. They will be made of wood or a composite wood, resting flat on the hatch. The wood is rotten from the continual moisture. Or maybe they are wood and resting in contact with soil, again we have rot. Sometimes there is wood, like decking boards, with gaps and water enters the crawl space from gaps in that cover. When there is a metal well at the entry, a professional metal cover is made to go with the well. The problem is, sometimes that cover is bunged up. In the photo below, this cover keeps the raccoons out, but there was plenty of room for rat entry to allow their activity in the deep dark corners of the crawl space.
Having a good crawl space cover seems like such a minor thing, but failure to have a proper cover can lead to water entry and damage from pests to the flex ducts, insulation and other important components that are down in the crawl space.
Steven L. Smith
Bellingham WA Home Inspections