Knowledge guide

How to Install Windows in a Cargo Trailer

How to Install Windows in a Cargo Trailer


Windows are a necessary part of any cargo trailer camper build, in our opinion. I mean, the whole point of camping is to get outdoors, right?

Cutting and installing windows is one of the first major jobs you have to do for your DIY cargo trailer conversion, and in this article, I am going to walk you through it.

Watch our video where we install both windows and a Maxxair fan in our trailer for more info.

Installing Windows in a Cargo Trailer

Cutting giant holes in your exterior is a pretty nerve-wracking job the first time you do it.

I mean, how can it not be? You start with these lovely, clean walls and end up with huge holes in them!

Don't worry! I will walk you through exactly how to do it, so it's as painless and least nerve-wracking a job as possible.

The Necessary Tools

I consider a few tools a must-have and a few that will just make things go easier. Check out the list below with associated affiliate links.

  1. Jigsaw
  2. Impact drill
  3. Safety goggles
  4. Hearing protection
  5. Table saw or circular saw
  6. Oscillating saw
  7. Drill press

The Necessary Parts

  1. Windows
  2. Self-tapping screws (hex-head)
  3. Butyl tape
  4. Plywood frame (two pieces of ½ in)

Buying Windows for a Cargo Trailer

There are a few types of windows you can install in a cargo trailer. Personally, I prefer the look and feel of the typical windows you see on any camper or RV. Looking online, these are simply called "RV windows."


There are a few places that sell them. I went with RecPro windows that I purchased off Amazon. Here are a few places you can buy windows for your trailer:

  1. Amazon
  2. RecPro
  3. Factory RV

We specifically purchased these windows, which seem to come and go as far as availability. But any RV windows will work fine.

Budget Option for Windows: Shop Windows

Shop windows or shed windows are pretty cheap and can usually be found for under $50. They might look a little cheap, and you will have to sort out the installation. Here is a link for a simple shop window.

Cutting Holes for RV Windows

Cutting out the holes for windows is really the only tricky part of the build. There are a few decent windows on YouTube that walk through doing this. I personally used the method in the video below to help me.

Here are the necessary steps:

Create the Window Frame

I used two pieces of ½ inch plywood glued together to make a 1-inch frame for my window. I just cut the shape of the window out with a jigsaw.

Draw your window outline on your wooden frame and make the cut. You can simply hold the window up against the wood piece and trace the outline. There is a decent amount of wiggle room with standard RV windows, given the window frame overlap, so it doesn't have to be perfect.

Cut Out Beams


Use an oscillating saw to cut any beams in the way. Be sure to leave some overhang of the metal beam, so you have something to screw the wood into. I show this in the video at the 7:20 mark.

If you install a large window, you may consider reinforcing the ceiling with additional beams made of wood or even a steel beam welded in.

I personally wouldn't want to remove more than one steel beam in my own trailer. That's one reason we went with smaller windows.

Cut the Window Hole

Use your wooden frame to trace the window shape on the wall. Ensure the lines are level and equidistant from the ceiling so that the window appears level from the exterior.

Warning: Use safety goggles and hearing protection when cutting an aluminum panel! Aluminum is very loud and non-magnetic. Meaning, it will damage your ears, and it's tough to get out of your eyes.

Use a jigsaw with a metal blade to make your window cut.

Voila! You have a window hole!

Now hang the wooden window frame so that the hole in the framer lines up with the hole in the wall and screw it in place any way you can by attaching the wooden frame to any beams it's touching.

Prepping Window and Trailer Wall for Installation

Use a drill to put screw holes in your window if there are no existing holes. A drill press makes this very easy if you are lucky enough to own one. Harbor Freight has them for pretty cheap if you have one in your area.

You may also consider filing down the edges of your window holes.

After you have holes in your frame, stick the window in the hole and use a drill to make pilot holes in the trailer wall. This is important, so you don't make a mess with butyl tape!

Now, take your butyl tape and press it against the window framer edge. Make sure you put the seam of the tape at the bottom of the window.

Install the Window in the Trailer

Listen: you only get one shot at this because the butyl tape is sticky as all hell! So carefully, place the window in the hole and line it up perfectly before you press it against the wall. Make sure you have the top of the window facing up! There is usually a sticker that should help you determine which way is up.

Press against the trailer, and the stickiness of the tape will probably keep it in place as you drill in your screws.

Bonus tip: Use hex-topped self-tapping screws. You are way less likely to strip out a hex screw than Phillip's head.

Bonus tip #2: Don't screw in the screws too tight! The aluminum window is thin! It is easy to overtighten, which will create an indention in the window frame.

That's it! Inspect your job and have a beer to celebrate a job well done!

Enjoy Your New Camper Windows

This was not a particularly challenging job, but it did require some planning. Ensure you watch our video where we install our own windows, and let us know if you have any questions.

Good luck!

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