Rebuilding the floor

After many missteps, trying to replicate a thicker joist type Shasta floor, and even buying some bargain basement Chinese plywood that could literally be ripped apart with your bare hands.

A fellow trailer rebuilder from an online forum finally talked some sense into us.  With his guidance, we decided to just "build it like we found it", using thicker 3/4" exterior grade plywood and 3/4" clear fir "joists" as spacers to make the floor the same thickness as before.  First we laid out the joists and coated them with asphalt emulsion sealer to protect the floor from the elements.

Then we secured the plywood with 1-1/4" deck screws and countersunk carriage bolts to the metal frame.  Each panel was coated with asphalt emulsion for waterproofing.

Finally, we reinstalled the wheel wells using 1/8" putty tape and hex head sheet metal screws from underneath.

Finally, after filling all the holes with wood putty, the chief helper manned the paint roller to add a protective coat of primer until we can install the final flooring material

Uh Oh Part 3

After our welder left, we did some inspections and found a hidden problem caused by the broken front support.  Without that crossmember tying the two frame c-channels together, the channels were able to twist, allowing the trailer tongue to lift.

As we had already had the crossmember reinstalled, we didn't want to try and straighten the frame, so we had our welder back out for an hour to box the frame in, preventing further bending.  We asked him to stitch weld the boxing to prevent heat stressing the metal here, as this frame is pretty weak in general.

Frame rebuild

Our wimpy broken frame was going to need some major TLC

So we came up with a plan.  Replace the broken crossmember, extend the frame all the way to the rear of the trailer and add "outrigger" supports to hold up the new floor

We went through several welding quotes, all near $1000, until we found a mobile guy who works weekends for $60/hour.  4 hours later, we had our frame plan realized.  Turns out the guy has a bunch of old trailers himself and was very interested in our future plans, so we'll keep him updated.