Teardrops n Tiny Travel Trailers

I won't be in a position to begin building my trailer until next spring so I have been doing a lot of reading and researching and a bit of experimenting. Since I have more time than money right now I was experimenting with some low cost/ no cost building ideas....Cardboard....

By layering cardboard cross grain (grain being the corrugations) you can construct a pretty rugged panel. There is somebody that built a kayak using this technique, and apparently cardboard furniture is a thing too. I constructed a 2 x 2 panel just to get an idea of how it would hold up. All I used for glue was some old school wheat paste, 4 parts water to one part white flour, and I am planning on using 6 layers but I am waiting for layer 4 to dry as I write this. The panel so far is as rugged as foam of the same thickness (approximately 3/4 of an inch).

My thoughts so far...
Cardboard an inch thick has an insulation R value of 3. Foam is about the same. Because you are lamenting your own panels you are not constrained by the 4 x 8 size sheet size if you want solid panels for your sides. My experimental panel has at least two separate pieces of card board per layer and in one case 6 so you can use any scrap cardboard you can get your hands on, you don't need refrigerator boxes. The biggest short fall I am seeing with this idea is rot. The wheat paste and cardboard are just asking to disintegrate so a proper water tight skin will be the most important part. I don't fore see this being an issue as glassed cardboard is already a proven building technique for smaller projects. When I get my panel done I will skin it and throw it in the tub for a few hours and see what happens.

Try this link. viewtopic.php?t=2566&p=24728

I am talking about using the card board as a structural/insulation panels. I had run across a couple of pics of skinning with cardboard but i was thinking of building with it.

I'd be interested in the weight of your panel
vs foam when you are done.....

I did a quick unscientific research and found corrugated board weight is 200 pounds/cubic yard versus polystyrene foam is 38 pounds/cubic yard.Big difference but if weight
is not an issue corrugated board can be free.

24" x 24" x 1" panel weighs in at 3 pounds 2 oz. so a full 4 x 8 panel would come in around 25 pounds. The only thing I can see this construction technique has going for it is that the panels would be almost free if you had a source of cardboard. Given the cost of a 1 inch foam panel is around $20 I can't imagine it to be worth the time to construct a cardboard panel. There may be a strength/durability advantage to the cardboard panel as it seems quite rugged even with out a skin but I am not sure it is enough to overcome the weight and fabrication time downside and once it gets wet it will probably be game over. It might be fun to do a build for the novelty of it, but from a practical stand point I can't cardboard as an efficient structural panel when compared to foam.