Just started and already stuck !

[cubflyer]

Hello from Atlanta, GA. My first question is the construction of the floor. If I make my floor a true 4x8 sheet of 3/4" ply then
if I set the walls (1/2" ply) down outside the edge, the overall width of the camper is 1 inch wider than 4 feet. if I set my walls on top of the floor then I have an exposed seam at the bottom. I could cut 1 inch off the width of the floor and then set the walls down past the edge. I now have a true 48" outside edge to outside edge. Since I will be using 1/2 ply for the front, top and rear It just makes sense the have the walls no wider than 48" outside to outside for standard width plywood Any thoughts ? I’ve watched so many videos and quite frankly, no two are the same. Thanks…Matt

[reaver]

If the exterior dimensions of the trailer can't exceed 48 inches, then I think your only option is to trim the sides of the floor. Is it absolutely necessary that it not be any wider than 48 inches?

[cubflyer]

While not absolutely necessary, making use of 48” plywood gives you the use of the whole sheet with no waste. Since I have not found any suitable plans, I am just going with the ideas I see on youtube.
Everything seems pretty straight forward except the interior cabinets. That’s going to take some head scratching. Back to the floor….I’m leaning to mounting the walls to the floor to give me a true 48”width. Matt

[cubflyer]

Also, can anyone chime in on wall thickness? I’m going to use plywood slab walls and plywood roof. I plan on insulating the inside walls. Is 1/2” ply enough, or should I make the walls 3/4” ? Matt

[GTS225]

Here's my opinions/thought......you'll still have a raw edge, whether it's at the side of the floor, or the bottom of the wall, soo.....what will matter is what you do to protect that edge against the elements.
If you're going with a 3/4" floor, and then 1/2" walls, it sounds like to your teardrop is going to get a little "fat". If final weight isn't a concern, then ignore that comment. If, however, you do have an upper limit, I might suggest you drop back to 3/8" exterior, and 1/4" interior plys, with a 1" foam core between the two. Many a tear has been built with even less wall thickness skin....like 1/4" inner and outer, with a foam core. It depends on the limitations of your tow vehicle. Some guys have even skinned with 1/8 Baltic birch, relying on the chance that it won't get damaged, but they're also utilizing limited towing vehicles. (Hybrids and small cars come to mind.)

Just my opine.....Roger

[working on it]

At first, I was planning on building my 4x8 squareback using 1/2" ply all around, but after I made my floor 3/4", and happened upon a great deal for 3/4" plywood, I switched over to 3/4"...

from an earlier thread, concerning flooring

...* I used thin underlayment on my floor, and due to good prepping, it has been flawless...as has my cabin structure.

* I started my trailer build using a 1/2" sheet of birch plywood that had been sitting unused in one of our sheds for twenty years. It was good quality, and hadn't warped or delaminated in any way, so it became the bottom of the floor (undercoated with automotive spray undercoat). I decided that I wanted a 3/4" floor, so I bought a sheet of Luan underlayment, which was 1/4" thick, and used Titebond2 and 38 Tek screws around the perimeter (plus eight 3/8" carriage bolts thru to the crossmembers) to securely attach it all.

* I made the floor before I learned of the polyurethane+paint thinner "mix" for waterproofing, but since I undercoated and filled all underside seams with PL adhesive, I figured that my floor would be effectively waterproofed after I put 2-3 ? full coats of polyurethane on the topside of the Luan. I guess it was sufficient since it once had two inches of standing water on it, overnight plus a full day, after I left a door ajar in a monsoon. No warpage or delamination, several years later.

...Here in Oz, the type of glue used is generally reported in the specifications on the retailers website.
For example, Bunnings tell you that their Australian structural ply is constructed with type A waterproof phenolic resin.
I bought plywood from various suppliers. With two exceptions, It has always had the type of bonding printed on the back.
I look for A-Bond, or WBP (water boil proof). South American Aaruco ply is all made with WBP, even their structural grades. Love it....

* My trailer is built from 3/4" Arauco plywood (no insulation), with phenolic resin between plies, except for the floor; I got a great deal on six sheets for $100 ??, with one side pre-sanded already. Once I studied the poly "mix" threads, I totally waterproofed the plywood before assembly, and again used PL adhesive inside and out (and in-between) all seams, for more waterproofing. 10-12 tubes. And afterwards did the same with poly "mix" basecoats, and multiple topcoats of acrylic farm equipment enamels. Ten years after the trailer was constructed/poly'd/painted, and after many modifications, there's been zero instances of wood rot or delamination. I love that plywood, too.

As for construction atop the floor, I simply placed the walls on top (with PL adhesive in-between), leaving the floor's edges exposed, but coated with several layers of the acrylic enamel paint (after a thorough soaking with the polyurethane "mix"). I add to that protection every couple of years, just to make sure. With the 3/4" walls placed on top, the side-to-side interior measurement is 46.5" (plenty for me, as I solo camp).

Sure, my trailer is overbuilt/overweight (or as GTS225 might say, "a little fat"), with 3/4" plywood (plus 1/2" oak board framing around doors, windows, interior A/C openings), and extra steel frame reinforcement as well, but it sure is strong. Did I mention that it is bolted together with steel brackets? as well as all the PL adhesive?

[reaver]

While not absolutely necessary, making use of 48” plywood gives you the use of the whole sheet with no waste. Since I have not found any suitable plans, I am just going with the ideas I see on youtube.
Everything seems pretty straight forward except the interior cabinets. That’s going to take some head scratching. Back to the floor….I’m leaning to mounting the walls to the floor to give me a true 48”width. Matt

Also, can anyone chime in on wall thickness? I’m going to use plywood slab walls and plywood roof. I plan on insulating the inside walls. Is 1/2” ply enough, or should I make the walls 3/4” ? Matt

So, I'm currently in the process of building mine. But, My floor is 2 1/4 inches thick.



The structure is 1/2 inch on the bottom, with 2x4 laid on their side for interior support, and 1.5 inch insulation. On top of that is 1/4 in ply.

The 2x4's are set in from the sides 3/4 inch, so that the wall skeletons can rest on that, and are then glued with PL premium to the 2x4, and fixed with long timber screws.

I used 3/4 in ply, with voids cut out for my wall framing. This made the sheets very light, but still very strong. I then filled the voids with 3/4 XPS insulation.





We then glued and screwed the outer wall skin to those skeletons. I went with 3/8 inch ply for the outer wall, which is probably thicker than it needs to be.

All told, I my walls should be 1 3/8 inches thick, without the PMF applied.