Pattern for the new floor complete. I'd needed to cut away some sections to replace the sills, so I needed something fairly stiff to bridge the gaps. I got a deal on cheap door skins, screwed them down in the corners for accuracy, and screwed overlapping skins over the top with construction adhesive. In the morning I pulled the screws and was left with a nice, rigid, accurate pattern to work with.
Old 1/2" ply and 1/4" celotex floor ripped out. I made a last-minute decision to replace the two joists down the middle, no rot or damage but full of enough nails (giant twisties, no less) that I don't want to hassle hitting them when I screw the new floor down.
New 3/4" MDO floor biscuit joined (yeah, I know, overkill on all counts) and cut to the template. I was pleasantly surprised that this was as stiff as it was with nothing but butt-joint biscuits holding it together- the temporary braces I'd planned on installing turned out to be completely unnecessary.
I'd originally planned on installing the floor as one big biscuited piece, but out of concern for the muscleworthiness of my help I decided to join the last 24" piece in place on the trailer frame, since it can slide straight in from the back.
Test fit for new floor, perfect fit the first time.
New floor back out and on the work platform, Marmoleum relaxing overnight prior to trimming. Cutting this with shears outside the trailer is a breeze compared to trying to trim it in place. Pattern is #3423 Painter's Palette, pretty wild period pattern which should be a champ for hiding camp dirt. It's actually a more vivid version of the linoleum that was originally installed in this trailer. The 79" roll width is a perfect fit for my 77" wide trailer.
New floor back in (after a last minute decision to insulate the floor with 1" rigid foam, seen here floating between the joists and frame rails- it'll get screwed to the floor later). Zero flop or bow carrying the giant piece of joined floor in, and it feels like walking on a concrete slab compared to the 1/2" ply and 1/4" celotex that that the 3/4" MDO is replacing. All that and it's considerably lighter and water resistant, it's a win-win-win.
Bolting the new floor in takes a few steps. First, I drill an 1/8" pilot from the underside through the sill/joist and floor, centered on the old 1/4" bolt hole in the frame by an aluminum spacer. Then I counterbore the bolt heads from the top with a Forstener bit, then drill the final 1/4" hole from the top with a cobalt bit, just in case I'm off by a hair on the hole on the frame side. Tap the bolt in, and you're good I start from the joists and work my way out, out of general paranoia. I used elevator bolts, reasoning that the reduced depth of the countersink and the greater resistance to punch-through would be more than outweight the reduced head strenghth vs. traditional carriage bolts. Engineering geek that I am I even set up a jig to test my theory, but my wife threatened to kill me if I didn't just let it go and finish the dang thing already. She would be correct to do so. Moisture stain on poplar framing in last shot may be due to airborne Big Gulp.
Rear floor section biscuited in, nearly done with frame bolts. I'm a big fan of Spax screws- zero splitting of lumber (even hardwood!), no predrilling necessary, they even cleanly countersink themselves. I screwed all of the sills and joists at 6" centers. This is one stiff floor, which is good, 'cuz I'm a big guy.
New stuff arrived today.
I'd planned on building in an '80s vintage Pelonis ceramic disc furnace, and assumed I'd remotely mount the controls and thermocouple inside either a vintage thermostat housing or, more likely, 3d print my own version. I finally realized that was idiotic. Nearly all thermostats, old and new, run on 28VAC, so all I need to do is hook up a $7 28VAC power supply and a plain old solid-state relay, just as if I was hooking up home furnace. I'll set the Pelois at full blast and plug it into an outlet that kicks on when the temperature is below threshold, no muss, no fuss. I found a very nice NOS Honeywell thermostat.
The original over-dinette light fixture in my trailer was MIA, and replaced with some generic ceramic fixture. Most similar canned hams have a traditional drum-style faceted glass utility fixture, which to my eye seems a bit visually bulky for the confined space. I found this lovely thing cheap online, only 5" wide and 6" long, nice, heavy glass shade, should be a big improvment.