Cannot tell for sure but if it is it is really just the start of it. Clean it well with a concrobium cleaner and leave it open to dry out and you should be fine.

Thank you! Actually, the leak occurred last year, but this part of the damage was only recently discovered when I removed the slide out organizers, intending to put new ones in. The water must have seeped underneath the baseboard and swelled the bottom shelving.

I would throw out that mat and put in a new one after a good cleaning and drying out of the cabinet.

The cabinet is dry. The cabinet bottom and sides will need to be replace. The straight board shows the warping. I am really scared to see the wood floor underneath. I am worried it will all be black mold.

Get it all opened up quickly, and do a good cleaning of the floor, under the shelving. Do you have a basement or a crawl space on your house? If so, you can look from the bottom, to see if there is an mold there.

Cat_ky, we have a finished basement with drywall. We should probably cut a hole in the ceiling.

"Cat_ky, we have a finished basement with drywall. We should probably cut a hole in the ceiling."

See what underneath the cabinet looks like first. Don't get crazy yet.

I would listen to millworkman - take a look to see what's going on under the cabinet.

FYI - I am not trying to minimize your concern re: black mold. I have systemic mastocytosis = a rare automimmune disease. I have allergic reactions to many things - including mold. I wind up in the ER probably 4-5 times/year due to anaphylactic shock related to allergic reactions (I have many more allergic reactions each year - but can control many of those at home with my epi pens). So, I've done A LOT of research re: types of mold because I need to be extremely careful about it (plus many other types of triggers).

I would not tear out the ceiling. Just see if you have any mold there when you replace the warped bottom piece. Why would you tear anything else apart. It might be just fine under that cabinet, and then you would have a ceiling hole to fix for nothing. Makes no sense. What you have now on the top, is very minimal, and most likely, none below it on the sub floor. If you had bad mold there, it would show through the sheetrock, or whatever the finished ceiling in the basement is.

The reason I might want to cut a hole in the drywall is because we discovered the leak from the water swelling the paint in the basement ceiling like a small balloon. The insurance company sent a company to dry it out. Lifting the mat under the sink mad me worry about whats inside the ceiling. I have probaly watched too much HGTV, lol.

" I have probaly watched too much HGTV, lol. "

Yes, you have. look under the cabinet first.

Yep, I agree with millworkman. Dont go do something that will then need repair, if there is no need for it. Patching a hole in the ceiling, can be a lot of work, and could show when you are done. Takes 5 minutes to get that board loose under the cabinet, and another 5 minutes to cut a new one and 5 more minutes to put it back, and then you will know if there is any mold to worry about. I suspect, there wont be, or that if there is, it isnt much and can be easily cleaned. Believe me, if you had in ceiling, it would be showing on the drywall, and you would know it.