Pondering a custom (tiny) camper build

[WesternDreamer]

I'm seriously considering building a tiny custom hard-side cabover-less camper to fit in the (nominally 6' 4" but really 6' 2") bed of my Ram 1500 pickup with the tailgate closed. My plan is to build a wood frame out of 2x2s and sideways 2x4s with rigid foam insulation and plywood sheathing. I would include a 14" x 14" opening in the roof for a MaxxFan.

I'll get into the design for the interior a little later, but my questions for right now are what thickness of plywood sheathing is recommended and what is the best way to seal it for weather protection? My initial inclination is to use 1/4" plywood for the interior and 3/8" or maybe 1/2" for the exterior, but the weight adds up quickly. I'd prefer not to get into fiberglass or aluminum and just treat and paint the exterior plywood. The camper will be stored inside during the winter, so aside from the occasional summer rainstorm, it shouldn't be facing too much inclement weather. My initial thought is to treat the exterior plywood with a sealer of some kind, tape the joints with EternaBond tape, and then add a couple of coats of liquid rubber.

Any ideas, suggestions, or warnings are appreciated.



Above is my frame design for the camper. It's 72" long, 79" wide, and 63.75" tall including the 3/4" plywood base. (The finished camper would be slightly larger including the outer sheathing.)

 

[Saint Nick]

Why not build a mini camper, but with the amount/size of timber you are planning to use, you're going to have a lot of weight in the frame alone. I think a rethink of the construction would be a good idea.

Nick.

 

[Jo_Duval]

I’m no engineer and not sure how much you can stretch materials it I think you have at least twice too much construction material

 

[Dusty-NZ]

Yeah , far too much timber .

Gotta keep it light . The 1/4" ply for the outside and 3/16" inside skin will make it really rigid , 1x2 frame plus extra for the four corners (so you can add some clip on jacks to make it easy to remove)

1" light weight angle metal for the corner seams , plenty of the appropriate sealer ..........

My camper has metal frame , it is just the purlins used in metal house framing , a very thin product , about 63mm x 35mm . and not much of it . 1/8 ply lining and 3/8 cedar shiplap cladding . It really could have been a bit lighter .
All up weight 610kgs, includes kitchen , clothes , food , water , toilet , etc .

 

[WesternDreamer]

Hmm... And here I thought using mostly 2x2s instead of all 2x4s was already compromising my structural integrity. I might have an issue with overbuilding things.

Any recommendations for a good (yet not crazy expensive) wood sealer? Also, has anybody tried using liquid rubber on the walls of a camper instead of just the roof? It seems like if it can seal a roof, it could seal everything.

 

[Deleted member 9101]

1×2's and 1/4" plywood... gule and screw every joint and you'll be plenty sturdy.

Also, I would fiberglass the entire thing. It will be soooooo much better in the long run than any other option. It not only seals it, but it adds strength.

 

[rruff]

I'm seriously considering building a tiny custom hard-side cabover-less camper to fit in the (nominally 6' 4" but really 6' 2") bed of my Ram 1500 pickup with the tailgate closed. My plan is to build a wood frame out of 2x2s and sideways 2x4s with rigid foam insulation and plywood sheathing. I would include a 14" x 14" opening in the roof for a MaxxFan.

Way, way, way overbuilt! Sandwich construction is so much more efficient.

Get 1" thick XPS foam. 3mm marine ply (or good quality) for the skins (both sides). Minimal stringers cut from 1x2s to the thickness of the foam. Glue together with PL Premium.

Exterior roof coating will work, but I'd really recommend a layer of FG and gelcoat if you want it to last.

 

[s.e.charles]

it's gonna leak

 

[rruff]

Also, I would fiberglass the entire thing. It will be soooooo much better in the long run than any other option. It not only seals it, but it adds strength.

Many years ago I built a camper using the method I described above, and was planning to use roof coating on the exterior (like I had with the previous one). When it came time I contemplated FG instead, but I'd never worked with the stuff. I consulted the I Ching, just for fun, and got Triple Dragon... which I interpreted to be the most unequivocal DO IT! I didn't regret using FG. If you are building with light wood skins an FG outer layer is a real good idea.

 

[Jo_Duval]

What does FG stand for? Fiberglass?

 

[rruff]

What does FG stand for? Fiberglass?

Yep! Wet layup. Mat and polyester resin. I was concerned because there were large temperature fluctuations, but I guess it isn't that picky. Never had a bit of trouble. The gelcoat final layer also is good for coating any exposed wood on door jams and such.

On my current build, I'm doing wet layup (epoxy) directly on foam (XPS) , with wood just for hard points and the perimeter of the panels (built in mostly flat pieces then joined).

 

[WesternDreamer]

it's gonna leak

Any (non-fiberglass related) advice to prevent that?

 

[Jo_Duval]

On my current build

Do you have a build thread?

 

[s.e.charles]

Any (non-fiberglass related) advice to prevent that?

if you're bound & determined to fabricate a camper, I would suggest using as little dimensional lumber as possible. pick an adhesive which remains flexible. source your materials from reliable manufacturers & distributors, but don't balk at their cost. the value will exceed the pennies saved over the life of the project. fight the urge to "get it done" when you know a small adjustment will result in a better end product. if you have a special event coming, rent or borrow something to get you by so you're not half-assing something at the last minute. ask 10x more questions than you think you should as peripheral advice can come of those conversations. allocate 2x the money and 3x the time you think you'll need. and then think about both again.

remember: only one thing in the world is waterproof, and that's a duck's bottom.

if it wasn't, he'd sink.