See my posts, pics about the wood rot in our trailer. Check under the lounges. Use a moisture meeter. Check the channel under the window, that is where the water ran down into the wall in ours. We could see the water line. Weep holes were made and the entry into the wall was sealed to prevent any further damage. Do find the source, first and most important. All can be repaired. The repairs were made by removing the lounge, floor removed and replaced w new ply and all is well. I even got a better vinyl floor than the original, at our expense. All work was done by my husband. It was not real expensive, just takes time to do it right.