List the components, furnishings and accessories for the camper, including door, window, stove, sink, water tank and other items. Obtain the precise measurements of all objects Sketch the floor plan and location of applicable items on paper.
Prepare the chassis to secure the shell by welding chassis tabs corner gussets. Screw 1/8 by 1/4 inch aluminum straps, which will provide support for the belly pan installed later at 16 inch intervals across the width of the chassis. Build the sub floor frame from 2 by 4 inch white oak lumber. Cut the lumber according to the width and length of the chassis. Bolt the frame to the chassis with sixteen 3/8 inch diameter, 3 to 3 1/2 inches long carriage bolts nut and washers. Do not attach the plywood floor at this point.
Make a template for the trailer camper's sidewalls out of cardboard. Trace the outline of the template on the back of the plywood and cut a jigsaw. Clamp the two sidewalls together and sand around the edges with a belt sander outfitted with course sandpaper.
Trace the outlines for the openings of the window and door on the sidewalls and make the cuts. Position the sidewalls on the chassis frame. Use the carpenter's level to ensure a level and plumb fit. Apply construction adhesive to the floor frame. Pre-drill the holes and squeeze adhesive into the holes. Secure the sidewalls to the frame with #14, 2 1/2 inch flat head screws. Fill the knots and screw holes with wood putty.
Fabricate roof bows for the camper. Measure the space between the two sidewalls and cut 3/4 by 1 1/2 inch white oak lumber to this length. Glue two boards together to create a 1 1/2 inch square a component. Mark lines 16 inch apart around the edges of the sidewalls. Apply construction adhesive on the ends of the roof bows and install. Pre-drill the holes insert construction adhesive and fasten the roof bows in place with two #8 drywall screws 2 1/2 inch long.
Laminate two 1/8 inch plywood sheets together and install to the roof bows with construction glue and staples. Apply the fiberglass covering on the roof and sidewalls according to the manufacturer's instructions. Install fenders per manufacturer's guidelines.
Glue 1 1/2 inch rigid foam board insulation between the roof bows on the interior side. Install 1/8 inch plywood to complete the roof installation on the inside. Follow the manufacturer's instructions for framing and installing a roof vent, window and door. Install 1 inch rigid foam insulation on the walls and cover with 1/8 inch thick plywood.
Install the interior floor. Apply 1/4 inch plywood laminated with fiberglass to create the belly pan in between the floor framing. Secure 1 inch strip of wood to the belly pan and the floor framing. Apply a sheet of foil-faced rigid foam insulation in the void. Secure 1/2 inch plywood to bring the floor flush with the oak frame. Seal the edges with silicone caulk
Follow the plan for layout and installation of the furnishings, including a bed, storage, cabinets, sink, stovetop and table. Add other accessories as desired.
