Hi Dokkodo
I really think you might want to still consider the metal frame option for the walls - I hear what you are saying about the aesthetics internally, but you can do that with strips of wood, placed anywhere you like, and have the choice of fancy wood types to boot!
I've not built one, or worked for a caravan company, but I've been watching the tiny homes scene for close to 10 years (as a possible option to never being able to buy my own), along with self builds, Earth Ships, boatbuilding (Father owns a wooden fitted yacht and has been talking about a refit for years), George Clarkes Amazing Spaces (with Will Hardy, mentioned previously who's a real innovator), and pretty much every program and hundreds of youtubes on renovating old structures both static and mobile inc caravans / horse boxes etc etc etc into a home, for
decades - man I'd LOVE a vintage Airstream, I know a guy who has one...... or an american style school bus - a la Bob Waldmire's Route 66 bus (google it, it's a beaut), anyway, so I'd like to think I've picked up a few things along the way.
Oh and I also studied architecture and construction at college for 3 years.
Anyway my point is this, there is one main rule for all of them, it's a bad design choice that builds UP TO a weight limit for a mobile structure.
One should always endeavour to BUILD DOWN as much as is reasonably feasable within a budget or slightly over if the cost is tolerable. Saving that weight now might well be required down the line - but you'll never know that until it comes to it, and by then it's too late.
For example there's a simple question, how are you going to fit out the kitchen area and "how much does a box of average sized tiles weigh?" - it's every small choice like this that most people don't take into account.
As for the fitted components inside, whether it be a few or festooned, there's only one mantra to follow "maximum storage, maximum storage, maximum storage".
150kg of weight saved (compared to the ali frame option as guesstimate) will give you a
lot more storage alteration options, and you'll be very glad of it - especially if you get fed up of having no washing facilities unless you intend to strip wash from the sink every day which will get old real fast when there's no site facilities; relying on site facilites will seriously hamper your ability to just "hook up and go, any time, any
place", there are a great deal of sites that are little more than a field on someone's farm with NOTHING in the way of facilities apart from a source of water.
You'll need to plan for that - or be forever tied to using a dedicated site.
Looks like you might have JUST enough room for a "bath in the floor" between the struts of the trailer - and as you're planning on having a log burner here's an interesting option
https://www.alamy.com/stock-photo-man-b ... 26067.html
Make the bath out of metal - copper preferably - and solder copper pipes to the outside of it, in continuous loops, several being better to have more pipes in the fire, that run through the stove fire in am unbroken loop, with a pressure outlet valve AND a cut off valve so you can cut the water from flowing when it's hot enough. The liquid in the loop is usually water but could be glycol (?) or a mixture for better thermo conductivity and will self feed cold > hot because of thermo dynamics.
or... *faded memory surfaces* aha yes! Easier still make a version of this:
https://gigazine.net/gsc_news/en/20160731-dutch-hub/
I'm sure the design can be modified to work with a log burner.
Lol, just an idea
The simplest way would be a simple solar shower option, black bladder on roof, heating water that outlets from the side of the structure, but they don't work in english winters !
Oh and don't forget to create storage cubbies in the floor either, best place for car batteries and heavy items, you've got at least the depth of the chassis and a little bit more you can use - and possibly give it some larger wheels, looks like you've got some room there too, before rubbing the underside of the main framework, far as I know it doesn't matter of the trailer is tipped slighty forward towards the car, and prolly preferable to being tiped back away from the car, so maybe get some height measurements on where the hitch will be heightwise when attached to a vehicle.
I've noticed in your more recent sketchup you've got freestanding furniture, in a towable structure this is also MASSIVE NO NO. They can move, shifting the weight and adding all sorts of complications - this is quite apart from the other point which is there is an awful lot of wasted airspace in between the legs of a freestanding chair.
Your first sketchup with a "box style / built in" unit is far more preferable - no moving parts except what's stored inside; however your coffee table on wheels is also a massive no, no.
If it were me I would do several things differently - if you would allow me.
The bed, I would remove that altogether
for now and make it part of the boxed seating arrangement - sure you'll have to make it and unmake it each day, or not as the case may be :wink: but it will also lower the centre of gravity at the rear, which is where all the fun happens if the weight isn't well distributed as MikeG stated - because I'm getting the impression you like to make things "chunky" - aka "weighty".
I would also not
statically build in the seating unit either, I would make it in sections that can be moved about on small rollers something similar to these:
https://www.amazon.co.uk/SODIAL-Sliver- ... 4321&psc=1
Maybe 1 longer and taller one for the main back rest and 3 or 4 for the seating - and here's where the clever bit happens and the reason for the rollers - when in transit they can be MOVED further forward over the axle, and then fixed down to the floor using some ali angle, metal plasterboard hollow fixings in the floor and these, which take up minimal space.
https://www.amazon.co.uk/sourcing-map-A ... ay&sr=8-38
You'll need to have fixing points in the floor where they will be placed for transit and when in "normal" use. There is one additional benefit - if you move the units over the axle it'll also give you the option to make a decent sized open space at the far rear should you need it - for storing lightweight items like a bicycle, surfboards and whatever else that can be
strapped and tried down to the floor using those self same metal fixings.
If you absolutely MUST have a bed you don't have to "make up" every day - you could consider a platform that's more central over the axle, that lifts and lowers on climbing rope (not paracord) using a pully system, with the cords arranged similar to a venetian blind, pulling from one point, with drop down legs so it rests on the floor, then the legs fold and clip up in place and you lift it to the roof again - you'll lose minimal headspace and you could even use the underside to fit LED's for main lighting - just add some spacers to the "bottom" of the bed and a sheet of 6mm plywood to create a cavity for the fittings and power unit (and the legs) - they use very little power and present an almost negligable fire risk if fitted / insulated correctly.
Sorry, I'm going on and on, I've got lots of ideas for a similar space and I envy you that you've got the chance to make it happen =D> - I'll be watching with interest.
And and it's not "cheating" to use the free resources here, I'd call that smart thinking.
Good luck ! (hammer) (hammer)
Edit - I was just going to say that I'm practically FIZZING with jealousy and I'd offer to help if you lived closer - then I clicked on your avatar - I can't repeat what I said but, we live in the SAME CITY, Bristol.
Seriously, I've got my own tools; maybe more than you as it's my profession (hammer) including things like a site saw, track saws, mitre saw, MFT's and trestles, clamps galore, etc etc and can offer time in between work and stuff as I'm self employed; it would be a lot of fun - oh and my car is large - a people carrrier actually with no rear seats, should you need materials in bulk.
Send me a PM if you need extra hands. Really.
Oh and one last, last final thing - my vehicle has a full on towing setup (from previous owners) 2 power outlers and a safety latch - in case you needed to move the trailer on site .
#muchtookeentobehealthy