Very hard if the whole floor as it means gutting the inside. Also get in touch with the manufacturer as if you replace the whole floor cutting it away from the wall you may cause the wall to drop.
See how a caravan is made on You tube and the one on the Lunar Solar 462 Delamination repair part 1 You tube video its in four parts.). if of course its because an area of your floor is spongy.,
bob, August 2014
