Introduction: DIY Camper Van Window Install

About: We're Laura and Louis. Laura is an educator and Louis is an engineer. With our powers combined, we make things and try to show everyone how we tackle projects in hopes to inspire others to get up and create!

We're finally tackling our dream project and converting a Sprinter into a camper van!

You can check out the first instructable where we installed the fan and solar panels on the roof:

In this instructable, we show you how to install sliding bunk windows! The link above takes you to our Youtube video showing all the steps. Check out the video tutorial and if you think we deserve it, a like and a share is always appreciated.

Onto the project!

Although we are installing the bunk windows on a Dodge Sprinter, the steps and preparation can be applied to almost any car and window of the same type.

We went with windows meant for an RV with a 1.5" wall thickness because they are a little cheaper than windows made specifically for a Sprinter, but required more work on our end to fit properly so in the end we don't think the difference in cost was really worth it. There are links below to both types of windows, so you can explore your options.


Below are Amazon affiliate links to the supplies we used for this project. Using these links helps us earn a commission at no extra cost to you, so thank you for helping us out!!

RecPro Windows (What we used) -

Sprinter Specific Windows:

Butyl Tape:

RTV Silicone Sealant:

Metal Cutting Jigsaw Blade:

Painter's Tape:

Step Drill Bits:

Step 1: Cut the Internal Brace

When installing windows, you want to make sure there is enough distance from another source of air so you can maximize the air flow throughout the van. In our case, the vent fan is installed right behind the driver's area, so we positioned the window toward the back of the van.

Before we can cut the hole out for the window, we needed to remove the vertical brace inside the van. We used an angle grinder with a cut off wheel to carefully cut into the brace trying not to hit the skin of the van.

We’ve seen some people cut only a portion of this brace and work around it, but once it’s cut, the brace doesn't provide any structural value, so we think it’s easier and cleaner to remove the whole thing.

Step 2: Clean Up the Burrs for Smooth Edges

Once we cut through the brace, it was held onto the skin of the van by some foamy adhesive and we just took a pair of pliers and pulled the brace off.

Then we used a flap disc on our angle grinder and rounded over the sharp corners and scraped off the adhesive with a flat head. Although a scrapper would have been smarter to use.

Step 3: Prep Before Cutting

We traced the perimeter of the window onto a piece of carboard and cut it out to make a template. We taped the template onto the wall of the van and traced around the perimeter with a marker. We positioned it by eye and then measured to the nearest reference point, so we can copy the position on the other side.

After removing the template, we drilled holes near each corner with a step bit so we can fit the jigsaw blade through. To minimize scratching the paint on the van, we applied some painter’s tape onto the shoe of our jigsaw.

Step 4: Cut Window Hole With Jigsaw

Using a metal cutting jigsaw blade, we started from one of the holes we drilled and cut around the marker line.

The first two sides are easy to cut, but once you get to the third side, the structural integrity of the cutout is almost nonexistent, making it super wobbly while you’re cutting.

We tried to stabilize it with painters’ tape against the body, but that wasn’t very helpful, so one of us held the cutout to keep it rigid, and it worked relatively well. Once we cut out the window hole, we filed the edges smooth and spray painted along the edges to seal the bare metal.

Step 5: Measure and Fit the Proper Spacer for Your Window

Like we mentioned before, the windows we bought are meant for RVs with a 1.5” wall thickness. To make up the difference, we traced around the perimeter of the template we made earlier on a sheet of ¾” plywood then used a 1” fender washer as a spacer to trace an even border around the template.

We cut out the inside and we were left with a rectangular donut we can use to fit between the window and the trim ring.

Step 6: Cut Out Spacer With Hole Saw and Jigsaw

We cut out the inside and we were left with a rectangular donut we can use to fit between the window and the trim ring.

Step 7: Add Butyl Tape to Window Trim

Now that we have the hole for the window cutout and the spacer made. The only thing left to do is add the sealant to the window.

We just pressed on the butyl tape around the window flange. One thing we didn't take into consideration was the flange has a slightly rolled lip, so we should have doubled up on the butyl tape to make sure there is plenty of sealant between the window flange and the van body.

Step 8: Clean Mating Surface and Fit the Window

Luckily we cut the hole large enough for the window to fit in without any extra cutting.

After dry fitting, we cleaned up the mating surface to make sure there are no debris that can impede the seal.

Then we fit the window from the outside. One of us stood back a few feet away to make sure it looked straight.

Step 9: Mount the Trim Ring

With one of us holding the window from the outside, we fit on the plywood spacer and then the trim ring.

We picked up ¾” long #8 self tapping screws to secure the window in place. Unfortunately the store didn’t have black screws in stock, so we got stainless which we might paint later.

Step 10: Gently Screw in Trim Ring to Window Spacer

We recommend using some lubricant on the screws before driving them in because we definitely broke a few on the first window and had to drill new holes in the trim ring. After learning our lesson on the first window, the second window installation went much smoother.

We suggest hand screwing to start and then lightly using your drill until the screws are in properly.

Step 11: Water Test Windows

To make sure everything was installed correctly, we water tested it…. And found a lot of leakage.

Step 12: Be Sure to Remove Drain Plugs Before Water Testing

After closer inspection, we realized some of the water ingress was due to tiny gaps in the butyl tape so we filled the perimeter with silicone sealant.

Most importantly though – we forgot to remove these drain plugs. So.. remove the drain plugs before water testing.

Step 13: Water Test Again

After taking care of those little mistakes, we have sealed windows! It’s going to be great having these windows to look out of when we’re hanging out inside the van and have the option to open them up to get a little cross breeze inside.

Step 14: Admire Your Work

We love that it’s looking like a camper now!

We still have a long road ahead of us before we can hit the actual road, so make sure to follow updates on our van conversion series.

Instagram: instagram/com/imee_made

Thanks for reading and best wishes for your next build!