Well, I had a local handyman build an addition onto a small cabin I own. (I didn't do it myself because it's an hour away near the lake and I simply didn't have time.) Well, it appears the guy used the cheapest subfloor he could. It doesn't interlock and there appears to be some dipping in the floor in between the joists, which causes to curl very slightly where the edges meet. Guess that's what I get for not specifying materials and going with a cheap price. I told the guy I would finish out the interior and only notice the condition of the floor when I started to do so. The 10 by 20 addition is being divided into two rooms - a bathroom and a bedroom. Here are my questions: - In the bathroom area I already have the shower installed. Should I install something like a hardie board on top of the existing subfloor? If I do go with a Hardie board, is 1/4" board enough or should I go with a 1/2" board? I am planning on install vinyl stick on tiles which can be grouted. I don't want to go with a ceramic tile floor due to the cold nature of the tile and the fact this is an elevated cabin on 6 by 6 treated posts. The bathroom is smallish - only 7 by 6 floor space with the shower installed - and I have yet to install the toilet and sink, so I'm open to anything. - In the bedroom, I was planning on installing industrial carpet with a pad. I think this will work good enough so the floor is not noticeable, but didn't know if I should consider reinforcing the existing floor first. If I do need to reinforce, would installing luan (or lauan) boards over the entire bedroom to help it out, or should the carpet pad help hide any subfloor issues? I appreciate any comments or suggestions. Thanks.