F350 Subframe / camper frame build Questions

[YnotDIY]

Hey ya'll, very new here and have been reading as much as possible about subframes and building technique, but had a couple questions and decided it would be best to just make a post.

Small intro
I'm planning to get an F350, delete the bed, and fabricate a camper off the back that will go over the cab. I'd like to build the frame in steel. After it's finished I'll be living in this full time with my partner and our dog, year round, for at least two years.

Questions
1) It sounds like people are building subframes out of 1/8" 2x2 // 3x2 .120 steel and I'm curious if this is also the general size people are using for the actual frame work of their campers. I don't want to overbuild this. My parameters are strong, inexpensive, and as light as I can go. I'm looking for simplicity and efficiency. ( I know it's weird talk from someone looking to DIY a living space off the back of a truck, but alas there ya have it haha.)

2) I THINK I'd like the subframe to just be a part of the camper body, (to save weight) but am having trouble imagining how I'd go about insulating the floor and closing in the underside of the camper in order to do this. Welding with thin steel sheeting is a possibility, but is that necessary? Wood seems like a bad choice since it will be exposed to all elements, maybe a composite material?

3) Exterior Skin - This is a big one I cannot find a solution for yet and I know it's my inexperience, so I apologize for that. Curious about options for materials and attachment techniques for exterior skin to a metal frame? What methods and materials are people using? Attach from outside? Attach from inside so frame structure is highlighted?

I SERIOUSLY appreciate any help, suggestions for previous builds to read, books, people to talk to ect. Are people in the Full Size section doing this type of build? I haven't seen many from what I can tell. If this post would be better in another area of the forum I'd appreciate direction with that.

I've been taking notes from @Motafinga Alaskan F250 build for the subframe and have been searching and reading for hours a day, I'm willing to put in the work! Just can't do it alone.

Thanks everyone, appreciate ya'll taking the time to share your knowledge so another person in this world can make an alternative life possible! Cheers!

 

[Motafinga]

Sounds like an ambitious and worthy project, I’ll be looking forward to watching your progress. I’ve never taken on a project of that scope but I would definitely think hard about whether you want the subframe attached/welded to the camper for several reasons. One being the ability to mockup and test the subframe independently of the camper being attached and also being able to make alterations if needed and being able to physically get to it. I don’t think it would really save weight anyways unless I’m missing something. There is great technology in composite panels now as far as the skin goes which I’m sure you’ve looked into. I believe most builds use adhesive to attach the skin and aluminum extrusions at the joints and corners ...not sure but you might even get away with no “frame” if you can build in the strength with the extrusion joints. Look at Total Composites as they make custom kits and I’ve heard good things about them, they can probably advise about the subframe attachment too. Good luck with the project!
Jeff