Spongy spot on floor

[duggger912]

I have a 2008 Springdale fifth wheel that has developed a soft or spongy spot on the floor. I know I will have to replace the flooring around the spot but I would like to know where the floor supports are before I tear into this project. My wife and I are full timers and I would like to gather any and all info about the floor construction as possible so that the repair time is held at a minimun. Are there any blueprints available and how do I get them, etc. The spot is located approx. 4 ft in from the entrance door, in front of the step to the bedroom and between the center floor register and the step right over the heating ductwork. Any help will be appreciated. Also I'm pretty sure I know the cause and I have corrected the water leak that caused this.

Thanks in advance

Steve