Pull the trim from the edges of the floor. To save some money, pull the trim off carefully for later use. Use the back of a hammer to gently pry the trim boards off the wall. When the trim is gone, remove the vinyl or carpet.
Check for damage to the plywood underneath the carpet or vinyl. Find any spots that are soft or stained black, as this might indicate water damage. If you have damage to the subfloor, it will need to be replaced, so map out the dimensions of a new plywood subfloor.
Use a crowbar to pull up the subfloor. Take note of the thickness of the plywood, so you can replace it with plywood that is equally thick.
Remove the subfloor frame boards, if they too are rotten, soft or otherwise damaged. Place 2-inch-by-2-inch boards in a frame on the floor and nail or screw into the camper's metal frame.
Measure and cut plywood for the new subfloor. Mark the locations of the subfloor frame boards on the camper wall with tape or a pencil, so you know where they're located as you install the plywood. Nail or drill the plywood to the frame boards.
Place self-stick vinyl or carpet tiles on the subfloor. Start in the middle of the room and work outward, for a professional look. Cut the end pieces to size using a box cutter, and put them tightly in place.
Re-install the trim you removed in the first step, placing it back in its original location if possible.
