Folding Camper Build I

I started the build of my folding camper last weekend. Starting with the base. The base is 4X8 feet using 5mm plywood and 1X6's around the perimeter with 2x2's in the corner. All joints are glued and screwed.

Here is the initial fit check and clamp up.

Here after the 4X8 rectangle was built, I glued the 5 mm plywood on the bottom. I screwed it every 6 inches or so but needed addition clamping force from various other weights. 

The bottom being only 5mm (<1/4 inch) thick is not strong enough to support any significant weight and will provide little insulation. The bottom will be further built up to form a sandwich of  two 5mm panels, foam and thin wood strips forming a Structural Insulated Panel (SIP).  Below I am constructing a 1 foot square test panel. I needed all my clamps for this glue up. This panel has a 6"X6" grid formed with 1/4" X 3/4" wood strips and 3/4" thick foam insulation. This insulation is the type with a plastic moisture barrier on each side with one sided silvered. I got mine at Home Depot HERE.

Below is the cross section of the test panel. The arrows are showing the 3/4" thick foam insulation from the corner that I cut off. I used this panel to validate the strength. It was tested with a load of over 150 pounds spanning 12" and had minimal deflection. There will also be runners on the bottom of the base to protect it and add more strength.

Now that I know the panel will be strong, I need to build this out on the base panel. The wood grid will have 128 squares in the foam matrix since the wood strips are spaced every 6 inches. This will take some time to do but seems to be worth it in term if the strength and light weight properties. The walls and roof will not need this grid and will be lightly framed.