We recently discovered our dishwasher was leaking under our flooring into the subfloor (formerly the floor – oak before the previous owner added pergo). We’re in the process of cleaning it up and see that there are spidering like dark marks on the floor that I’ve never seen before. Does anybody know what it is?
Best Answer
This looks like fungal growth to me. Specifically, it looks like the “roots” of honey fungus. I’ve seen this before on a stack of old PT lumber I had sitting outside for a few years.