We recently bought a house with a mobile home guest house, and allowed a friend of a friend to stay in the guest house for a few months in exchange for minor repairs. The guest house is now empty and smells of dog urine, so we pulled the carpet up and found mold in the OSB sub floor. I dumped bleach full strength on it, and opened all the doors and windows for 48 hours. The mold has to be recent because there isn't much there, and it is clearly where the dog was urinating. My question is what now? We are going to put laminate flooring in, but want it to make sure it is not going to grow back. Thanks!

Personally, I'd replace the OSB.

Bleach does attack urine and it does kill mold spores. The problem is that it can't always get into all of the cracks and areas where it might be.

You need to use a mildewcide as well as the bleach treatment to make sure it will not come back. If there is only one area and you have no damage to the underflooring you should be okay by ditching the rug. Don't put down any new flooring until a few weeks go by and you can see if any other area is attracting mold or the original spot has not come back. Sometimes mold spores can linger. Have you tried washing down the walls of the room where the original spot was as well?

No, I haven't wiped the walls down, I just painted them the day before we decided to replace the carpet. Once I got the carpet out, I did vacuum the OSB except where the mold is. There are 2 spots about the size of your palm in the corner of the room. It isn't solid it kind of winds around within the area. It isn't into the wood, it looks like it is on top. So bleach again, then mildewcide? Where can I get that? Before I put the flooring down I am going to paint the floors with a product like killz.

I will be leaving in about a week as I travel for work. I am hoping to remedy the problem before I go. I have been getting the guest house ready for a friend to move in to care for my animals and property while I am gone. She is willing to live on the OSB so I can make sure the mold isn't spreading before I put the new flooring in, but I don't know if that is safe for her or her animals...