We have a 2011 Yellowstone, 32 foot Class-C. We have had to have both slide floors replaced. I found some YouTube videos on how to do it, but when I got to the part where you need a forklift to remove the slide I decided the job was not really a do-it-yourself job.
The first repair was the slide with the couch and stove. The observed problem was the couch and floor were rocking when people sat down or stood up. The actual problem was not visible until the slide was removed by Pocono RV, Wind Gap, PA. The bracket that held the floor in place broke and was deemed a design flaw. $4,000 and 6 weeks later the problem was fixed.
The second repair was the slide with the bunk beds and master bedroom wardrobe. The "black trash bag" moisture barrier under the slide was ripped by the roller holding up the slide and the particle board turned into mush. This repair was done by Camping World, Kingston, NY. The repair included a moisture barrier that is more of a thick laminate and metal runners were placed over the rollers. $9,000 and 4 weeks later the repair was done. Here are before and after pictures.