Please tell me more. What model do you have?
This may sound strange but we fought a major water on the floor issue for a few years. The dealer I bought if from in '07 said that the bottom seal was leaking and filled it with silicone. The coach was a '05 Vectra 40FD. I traveled for an extended period of time in areas where it didn't rain much. When I did get into a rain situation sometimes the bed area floor would be wet and other times not. I sealed around the windows and checked the seals at the slide roof, caulked and taped. I still had water. Brought it to a couple of dealer and spent many bucks just to continue with the issue. When mold appeared in the ceiling liner over the bed I was really upset and went to ANOTHER dealer. They failed miserably once again. I finally bit the bullet and made an appointment with the factory service center in Forest City. They got my money back from the last dealer and rebuilt the slide roof. The roof seam behind the inside wood trim had failed. That is where all of the water was coming from.
Please take the time to examine the area along the edge of the roof and walls on all of your slides. Use the latest factory recommended sealant to correct any failures in the seal you may find. It is recommended by the factory that the old caulk be removed and the surface cleaned before applying the new. You may have to remove the toppers to see the seam under them. (Know what you are doing before you attempt this.) On the inside, behind the wood trim, move the slide in enough so you can get a flashlight and mirror up there. Clean and caulk as necessary.
Unless you know of a really good service center don't trust this to them. Go to the factory first. This service is about $2000 and should include the main roof also. Once it is done correctly you should be in a better position to keep it up.
Another cause of failing seams can come from a slide becoming out of adjustment over time. This is easy to detect. Simply check the compression of the wall mating gasket. The gap from bottom to top should be about the same. If the top is compressed hard this puts stress on the roof to wall mating.
I do hope this helps. Water leaks from the plumbing are bad enough. But from the structure they are very stressful to the budget and happy camping mode.
Rick & Melissa Young & Dawson, 2011 Itasca Meridian 40U, Freightliner XCL, Cummins ISL 380HP/DEF, Allison 3000 MH, 2014 Honda CR-V, SMI AF1, Blue Ox tow equip., TST 507 TPMS, TruCenter steering control, Hughes auto transformer.
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