Soft/uneven floor in mobile

[sjthaxter]

We are planning to renovate one of the bathrooms in a 20 year old double-wide. The room is on the 'join', and the floor feels uneven and maybe soft under the carpet. I'm curious what we'll find when we pull up the carpet, and how hard it is to replace the subfloor? or whatever it is under there. Does anyone have an idea what we might find? Is replacing something like that within the capabilities of a rookie DIY'er?? Thanks for any help or tips.
Regards,
John & Sue

[HayZee518]

you'll probably find chipboard where plywood should be. probably 5/8 inch thick. its fastened into the "A" frame of the mobile undercarriage with square head metal self tapping screws. from what I've seen underneath one of them, there's like cross purlins that span across the "A" frame welded to the cross members. you may find pressure treated hard to come by in your state - check the building inspector's office first.