When I did the concept drawings I was thinking of using 1/ 2 ply. This is what I used on the Tiny trailer build and it was overkill to the max. The trailer was extremely heavy. I used full dimension lumber (full 1X4 s, 2X8 s etc,) before I realized that half dimensions would work just as well. So came the Weekender build. The dimension of the weekend is such that only two seams need to addressed (the floor and the top).  The sides are 8’ foot and 6’, so the sides are well with the dimensions of a 4X8 sheet of plywood and seams between the panels are kept to a minimum.

Construction technique:

Plywood owes its strength to the plys that are laid and glued bi-directionally. I take advantage of this tendency to use it for the exterior walls; However 3/8 ply alone is too thin and will bow and warp.  To counter this, I added framing strips to the walls at all connection point and at various intervals. This allows for stiffness and extra surfaces to attach to – You simply cannot screw into the end grain of plywood and expect a solid joint.  All joints are glued with construction adhesive and screwed for strength (I used about 8 tubes).  The adhesive increases the contact area for a good mechanical/chemical bond.   I did a test on this construction/ gluing method and literally ripped the first two layers of plywood trying to separate the pieces. The construction adhesive I used was liquid nails along with course thread drywall screws. Use rough thread screws instead of fine thread drywall screws.  Rough threads will grip the wood better, will countersink themselves, and are less likely to strip out. The wood strips were cut from a 2×4 on the small side measuring ¾ X 1 ½ .  This created a ¾ in cavity which I filled with ¾ closed cell foam insulation.  The foam insulation is about ¾ in. I bought it at Lowes.  Tried the regular pink home fiberglass insulation but found it to hard to work with and if it become wet it retains the water (plus the itch factor).  Not a problem with closed cell foam. I then added the interior ply – again with adhesive – but using finishing nails instead if screws (much easier to hide). Remember –use the structural strength of the plywood and adhesive to your advantage.  When the construction first begins the trailer will seem flimsy, however as more pieces are added and box becomes complete, it becomes more rigid – and when the entire frame is bolted to the trailer – well “it ain’t goin’ nowhere”.

Floor:  ¾  inch plywood – very sturdy and no need for framing beyond the actual trailer it self.  I used a sub frame constructed out of 2×3 s to support the camper floor over the trailer (A 4×8 no floor purchased from tractor supply company) Both sides of the floor were painted to seal the plywood.  I applied sheet metal to the underside of the floor to protect it from road debris and water spray. Bolted the entire structure to the trailer.

Screws and sealing:  The screws will vary in length the most common will be the 1 ½ .  These are used to hold the strips to the plywood while the adhesive sets – also provides a mechanical bond. However you will need 2 1/3 and even 3 inch screws to fasten the walls and flooring to each other.  One the last page of the small details shots on the website, there is a picture of the sealant tape – peel & stick butyl tape.  After I painted all the exterior with two coats, which seals the plywood, then I cut the tape and used it to seal the edges which are then covered with flashing.  Believe me, once this stuff is stuck in place, it isn’t going anywhere.  It is the same stuff used to seal gutters and roofs.  Attached the flashing with some self-tapping screws (1 1/2 x 1 1/2 drip cap metal flashing bought from Lowes). The peel & stick butyl tape seals the screw. I did not use any silicone on my project – just hate the stuff.  The are many other forms of sealers that do the job just as well and are easier to clean off in case you make and mistake and need a redo.

Also the one seam on the roof is place so that a 2X3 roof support falls underneath.  Remember how I mentioned about the use of adhesive on all joints? This has an added benefit of sealing the joint (liquid nail is what I used – it is waterproof and holds like hell!) Apply a generous amount. I made sure every crack was sealed and then painted the joint with a liberal coat of paint. I built this during a particularly heavy rainfall season and no leaks occurred.

Final notes:

* I learned the hard way that flat roofs tend to have low spots.  However this can be eliminated by adding a slight bow in the center – about ¾ to 1 inch.  This slight bow will allow the water to run off and still allow for flat edges.  No need to cut complicated shapes.  Also I capped the roof with sheet metal with one seam down the middle, which I sealed with peel & stick butyl tape.

* I did not run any of the electrical inside the walls. I wanted the build to be simple and easy to maintain.  a tip: if you plan on using 120 AC 30 amp power, then make sure that the power cord outlet is on the driver’s side of the trailer (when hooked up to the vehicle).  Most RV and state parks have the power distribution on this side of the pull in.  It just makes sense not to have to turn the trailer or have extra cord

* Please note that the drawings were for concept to allow for changes as the build went along.  However you can place the windows and AC anywhere. Just make sure that they surrounded by framing strips.

* Flush mount windows - normally found on mobile homes - work better than what I used.  I found mine at a salvage yard new for a low cost.

* Very light weight, I can move it around the yard by myself fully loaded. Weight: 1060 lbs  fully equipped.