Floor lifting under vinyl

[druganjk@gmail.com]

I have a 2018 Thor Miramar 35.3 and in the bedroom in front of the vanity the floor has large bumps and raised areas one is almost 1ft in diameter. The vinyl is fine. What is the sub floor and what is causing this. Has it happened to anyone else. Thanks

[javelin]

I am not sure if this is your problem, but I have seen the long screws that hold down the plywood sub-floor to the metal I beams of the chassis actually unscrew themselves over time due to vibration etc. If that is the case, you would see the vinyl floor lifted into a cone shape as the screw rises from below. If this is your situation, check under the coach directly under where the vinyl is tented and see if one of the screws coming through the I beam is shorter than its neighbors. If yes you can grab the screw from below with a small vice grip and literally screw it back down to allow the vinyl to return to normal. It might help to prevent a re-occurrence if you touch the offending screw threads with blue thread locker just below the I beam, after it is returned to its proper position.
If the screw thread is no longer visible from below the I beam then you might have to play surgeon and just carefully cut open the vinyl at the very top of the screw, just enough to allow a screw driver to re-seat the screw back down. The vinyl cut should be very small and perhaps a very small dab of vinyl glue will help seal the cut, once the vinyl has returned to its proper position. It is a PIA. Good luck.