I have been trying to get RID of a smell with no success. The smell is in a shared closet space between my unit and another unit in a basement (duplexed down units with first floor above grade). The smell is so damp and musty and just terrible. This is true especially in the summer. I want to sell this place, but people have been opening this shared closet and are immediately like what the heck! I have noticed it all along, but in the winter it is faint. My spouse says he did not notice it, but at least 30 potential buyers were not okay with it and noticed it in the Summer...no one really commented in the winter, but I always smelled something. We put in a dehumidifier which we empty every single day because it is full (see in picture the type of dehumidifier), but we cannot for the life of figure out where the moisture is coming from. One person told us it was likely coming out of the floor....I have no idea if this is the case...it almost looks like plywood is on the floor. I guess this would be a subfloor? In one of the pictures, it shows where the door opens to this shared space right out of our den. I am at my wits end trying to figure this out. I have tried essential oils, carbon, baking soda, the dehumidifier (which feels completely up in one day). It is closed off in the closet and there is no window or any way for the smell to get out unless we open the doors to our unit and then the units smell! We cannot smell it at all in either unit with the door closed. It is sooooo bizarre. These units are duplexed down to the basement. It is absolutely puzzling me and has kept us from selling our unit after a winter deal fell through. When we started showing in the summer, the smell was so strong as it usually is in the summer. I guess we never paid attention because we never go in there unless getting something from storage. Can someone tell me what I can do and what type of floor this is? It kind of looks like it has gray paint on it, but it is certainly some type of wood or a material like it. Should we get someone to rip the floor up? Why is the smell not in either unit? Please help!