Noticed the floor is spongy on our 2009 Flafstaff TT It's been setup for 2 years on a site in Delware. At first I thought it was the stabilizer jacks being used this long but now I'am thinking it's...
Even more likely that it is the relatively thin (but lightweight) flooring showing signs of fatigue. I traded mine before I fell through and the floor was never even damp.