Design goals:
- light weight
Need to be able to carry a lot of stuff inside
- highly insulated
For desert conditions, want to be able to last at least a little
while before turning into an oven
- demountable cabin
Retain use of trailer independent of cabin
Trailer:
- RedTrailer 4x8 or 5x8
If the 4x8 is chosen, I will want to build frame larger than
trailer bed to accomodate queen-size mattress with minimal fuss.
The weight difference between the 4x8 and 5x8 is surprisingly
small (255# vs 263#), so the main motivation for the 4x8 would be
to have the wheels be under the frame for looks and aerodynamics.
Plan is to put leveling jacks on 4 corners of trailer. Can they
be bolted on? Is the one that redtrailers sells
(http://www.redtrailers.com/ShowItem.asp?id=53610)`good enough, or
is there a better one easily available?
Floor:
- Construction
2x2 (or 1x4?) lumber with plywood skins and rigid insulation. An
open question is how thin can the skins be? Plywood is heavy.
I'm guessing that 3/8" might be enough for the top, and 1/4" for
the bottom.
Bottom will get the customary roofing tar treatment.
What about using the stake pockets in the trailer as attachment
points for the cabin? Drop 2x4 of the right length from the
bottom of the floor to slip into the pockets.
4x8 trailer necessitates accomodating the wheels in the floor.
How much room is needed? Is it worth trying to build the floor
thick enough to completely clear the wheels?
Would it be worth making the cabin a bit wider than the trailer
wheels and longer than the trailer bed, and attaching the leveling
jacks to the cabin floor, so that the leveling jacks can lift the
cabin off of the trailer? Or is that going to necessitate
building the floor a lot stronger than it would otherwise need to
be?
Walls:
Plan to use the Cub/Modernistic profile Make the main arcs by
laminating 1/8" strips as seen in the 'lightweight design' thread
on T&TTT forums, but make it 1 5/8" (nominal 2") wide. Frame the
rest with 2x2 (or 1x2 on edge?) and fill the voids with rigid foam
insulation sheet. Again the question is how light can I make it?
Is 1/8" plywood enough if epoxy-based boat hull paint is used to
finish? I have no need to sit on top of my trailer
Attach to floor with screws and glue. May need to accomodate
wheels in wall design too.
Galley/Rear Wall:
Minimal--see 'lightweight design' thread again. Do want to figure
out a place to install a PetCool A/C.
Ceiling:
1/8" ply on inside, 1x2 rafters, insulation (what's best here?
kerfing rigid foam, or trying to find flexible foam?) and 1/8" ply
on outside.
Galley Lid:
As for 'lightweight design' thread.
Doors:
As for sides, probably rectangular for easy construction.
Windows:
Like to find some double-paned ones for thermal efficiency.
Exterior Finish:
The Dr. Rot treatment as outlined by Mike.
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