So I built a wood frame to attach to the metal frame. This would be where all the forces on the body get transferred to the metal frame. It did not have to be super strong since the rest of the body would help with the strength.
I used the Kreg Joint to fasten the pieces of wood together. I also used a bunch of type III wood glue which is water proof to help hold it all together too. Keep in mind this is this is your last point to make sure everything is squared up. After this every angle that is wrong will just compound.
After this I combined two sheets of plywood with a scarf joint and laid it over the frame. Using a pulley system I held up the 3/4″ sheet of plywood. I then applied a liberal amount of caulk then lowered the plywood onto the frame ensuring all the bolts stuck through. Then clamped it tight. I then used a few screws to secure everything in place.
The way the bolts are setup is I created a pocket in the wood frame. Put an SS bolt and washer in there. Then drilled a hole in the plywood to access the Allen head to tighten everything up.
Once everything dried. I flipped over the floor and applied a heavy coat of roofing tar to it to seal the wood and protect it from flying road and off-road debris. This will help prevent it from rotting. Then using my pulley system again. I lifted the plywood again and lowered it down onto the trailer lining up all the bolts with the bolt holes.
After the floor was in place. I tightened down all the bolt holes and let the tar dry. The tar also helps secure the floor to the frame along with the bolts.
Secondary False Floor:
I went with a design that had a secondary false floor. This would allow me to have storage and hold the water tank above the primary floor while still being under the secondary floor. This process was done after the walls and ceiling were already installed.
I installed 1″ x 2″ boards onto the walls to support the false floor then made a center divider to support this floor and to prevent it from sagging. This divider will also prevent items from sliding into the water tank section and to keep things more organized. Along with this at this time I placed my water tank in place to ensure enough room and glued down mounting points for it. Then I installed studs into them to bolt down the water tank straps.
After all the supporting members where installed I then grabbed a 4′ x 8′ sheet o 3/4″ plywood and cut it down to the appropriate length. Next I drew out where I wanted the access holes in it to reach both sup floor areas. I made sure when cutting out these areas I did not destroy the cut outs as these would be used as the access doors. Along with this I glued on 1/4″ strips of plywood underneath to support the doors from underneath. As you can tell you can never have enough clamps.
Next I glued down the false floor onto all the supports. The cut out for the water tank is large enough to remove it if needed!
What it looks like with the doors and everything installed.