Things You Will Need
Welding/soldering iron or torch
Utility trailer with tongue and wheels
Latch and hinges
½ inch thick plywood boards
Polyvinyl trailer flooring
Standard trailer stud mount traffic tail lights
Standard trailer license and lights bracket
A ready-made enclosed trailer will cost upward of $1,300. You can build your own enclosed trailer for about half that price, using a ready-made utility trailer with wheels and materials to build the floor, wall and roof of your trailer. Your door can be handmade of wood with a bolt handle and lock. An enclosed trailer must be registered with your local DMV and a license place must be placed at the center rear of your trailer.
Decide the size of your enclosed trailer, such as 4 feet by 4 feet or 6 feet by 10 feet, then obtain a utility trailer closest to that size. You will build the sides of the trailer to fit inside the existing mounting slots of the utility trailer and wheels.
Measure the utility trailer to determine the precise center. Place the axle in the center of the utility trailer. Mount the tongue on the cross bar aligned to the axle. The tongue is the triangular piece that attaches the trailer to the transporting vehicle with a ball bolt.
Turn the utility trailer upside down and secure the tongue onto the cross bar with screws and bolts. Attach the latch to the trailer at the center. The latch will keep the trailer balanced when in motion. The hole at the edge of the tongue will be attached to the back of the transporting vehicle with a removable ball bolt.
Cut five pieces of plywood for the four sides and roof of the trailer. Solder liquid nails every 12 inches of the angles and sides of the trailer to stabilize the plywood and as a rigid foundation for the roof of the trailer.
Use a utility knife to cut the polyvinyl trailer flooring to size before installation of the flooring to the trailer. Polyvinyl will provide traction and weight to your trailer floor. Tack the edges around with nails or caulking to prevent curling.
Apply flexible aluminum sheeting to the outside of your completed trailer, one piece for each side and the roof of the trailer. Secure the aluminum sheeting with the welding torch, using nuts and bolts with caulking at the edges to make the trailer airtight.
Install the trailer license and lights bracket to the back and sides of the trailer. The side lights should be spaced 12 inches apart and should be smaller than the standard rear lights. Attach the traffic tail lights and secure with the bolt and screws.
Measure every piece of material used to build your trailer and check the fit before welding it together to prevent the need to repair your enclosed trailer.
Use rust retardant aluminum sheeting on the outside of your trailer.
Your enclosed trailer must be registered with your local Department of Motor Vehicles in order to be street-legal for transport.
If your enclosed trailer is too large to stop under the inertia of your transporting vehicle, then you will have to install brakes to your trailer.