Adding a window to your cargo trailer will make it more airy and will let you enjoy the view outside. For a cargo trailer with thin walls, you may need to build sufficient framing to support your cargo trailer windows and not weaken the walls.
The first thing you need to do is to plan the size, type, and placement of the window. Next, you need to:
Make a frame for the window
Build a wooden frame from square-shaped timber. This makes it easier to fit the window to the opening, provides support, and acts as a stencil when you cut out the window opening.
You can either make the wooden frame first. Or you can measure and cut through the wall and then frame the opening with wood.
Cut out the window opening
Use the wooden frame you made to mark the placement and size of the window opening on the inside of the van. Drill small holes in the corners of the outline to guide you as you make the exact same outline from the outside of the van. Use a jigsaw to cut through the outline you drew on the wall of the van.
Install the window
Seal the edges of the opening with rust-proofing primer and sealant. Attach the wooden frame to the window opening using adhesive. Use screw clamps to keep the frame in place for about two hours.
Position the window inside the frame and screw it in. Use an elastic sealant on the outside of the body to seal the window.