How to Install a Window in your Van | Sprinter Van Conversion

Written by Freedom Strider

On March 28, 2020


Find the right window

Every make and model of vans have their own window shapes and sizes. The window size also depends whether you’re fitting it on the left/right side, at the front, the middle or the back. Also, now is the time to consider whether you want any of your windows to open.

We got our window from VanPimps, they had a huge selection and you can search by van type to right the right window.

diy window install - van conversion


Create sparks with an Angle Grinder

To fit our bonded window, we needed to cut out a section of the van’s side, and there is a nice template to follow when looking from the inside.

Before we cut through it, we needed to use an angle grinder to cut a channel in the support braces, otherwise the jigsaw might have broken.

We drew straight lines across the support beams with a sharpie and ruler, then created lots of sparks as we cut the support braces away.

Be warned: Angle grinder sparks are very hot. They can easily melt through clothes, seats, glass etc…so wear goggles, gloves and move anything flammable as far away as possible. 🔥

diy window install - van conversion


Holesaws – whoop whoop

Instead of trying to force the straight jigsaw blade round a corner (which wouldn’t have ended well), we instead used a holesaw to carve the curve of the corner. 

We initially were going to use a 10mm drill bit and drill lots of holes around the arc of the corners, which you can do if you don’t have holesaws, but then we found a pack so yippie!

We placed the holesaw on where we wanted it to cut, marked the centre with a pen to know where to start drilling, then proceeded to cut all 4 corners out. 🕳️

Honestly…very satisfying.

diy window install - van conversion
diy window install - van conversion


Make a big hole in the van

Moving to the outside, the 4 corner holes gave us a reference of where to cut, so we marked a straight line between each corner and used a Jigsaw with a metal cutting blade to cut it out.

You can use an angle grinder, or even a metal nibbler – the angle grinder probably wouldn’t have given a clean straight cut and we didn’t have a nibbler, so jigsaw it was.


Since the van is not at all straight, even the window cavity cutout isn’t a straight line. 📏 We cut the bulk of the metal away but had to do a second pass with the jigsaw to cut the remainder of the metal.

One of us stayed on the inside directing whilst the other cut from the outside. In hindsight, we probably should have done this for the initial cut to save time…there’s always the next window…


File it smooth, and rust protect

We broke out the files and sanded the sharp raw metal edges smooth. Not absolutely needed since we will cover it up and never see it, but more for peace of mind.

After filing, we generously used our trusty Hammerite paint to rust protect the raw metal edges and left it to dry for an hour.

diy window install - van conversion


Add a rubber seal (optional)

Our van window kit came with a rubber seal. Since this was our first window, we dutifully installed the rubber but we don’t like the look, so we will be removing it.

It took a bit of manipulation with a rubber mallet to coerce it into the correct place around the inner metal skin, but we got there. 🔨

…oh man, this is going to be hell to remove.

diy window install - van conversion


Hmm…we better close up this hole now

Once the Hammerite had dried, we used alcohol on the metal around the cutout to clean it, and applied the window primer in an even bead a couple of centimeters from the edge of the cut all the way around.

diy window install - van conversion


Dry Fit the window

Before we commit to sticking, it’s always good to double check you’ve got the right window…hmmm one would argue that should be done first. 🤔

Anywho, as the window was held up to the hole, on the inside we drew a pencil mark around the perimeter of the hole on the window. This tells us where not to put the primer beyond, as it would be visible from the inside.

diy window install - van conversion


Prepare the window

We had our window set on a table.  We unwrapped and cleaned it (with glass cleaner), used the glass activator wipe in the kit to ensure the primer will stick, and then applied a bead of the same primer around the edge of the window, being careful not to go over our pencil line.

diy window install - van conversion


Apply the sealant

The window sealant is very very VERY thick and gloopy stuff, and stains everything! It was a pain to squeeze out the tube using a regular caulking gun (most professionals use an electric caulking gun, and we can see why). 😣

Also, the type of manual caulking gun you use also makes a difference. We were using the cheap options on the market, but then the bigger universal ones (which can accept any sized tube) can give you more leverage and force, making it easier – and they are much cheaper than a battery powered one.

A tip we learned is to leave the window sealant near a radiator to warm up before squeezing it, at least now you can save your fingers the pain.

Apply the sealant to the van, on top of the layer of primer previously applied, not to the window. 

The key is to get one continuous bead all the way around, with no air bubbles. It is best as you get to the end to overlap the sealant so that absolutely no water can get in.

diy window install - van conversion
diy window install - van conversion


It is best to buy a 2nd tube of the window sealant, just in case. Technically, one tube should be enough, but we did end up needing to open the second tube, naturally it depends on the window size you’re installing.

If you don’t end up using it for the window, it is good stuff to use for other things in your conversion. You don’t want to be in the situation where you have ¾ of your window stuck on.


Operation ‘Stick Window’ in affect

Find a second human to help you lift the window into place and carefully press the window up against the van, ensuring you have even pressure and an even panel gap around the edge of the window. 

We pressed the window for around 5-10 minutes to allow the sealant to stick properly, and used duct tape to tape the tops of the window to the van so it doesn’t slide down as the sealant sets.

Duct tape is magic, and should be worshiped.

diy window install - van conversion


quick look

Quick Steps Overview:


  1. Pick the correct window
  2. Angle grind the support beams
  3. Cut the corners out
  4. Use jigsaw to cut the rest out
  5. File and hammerite edges
  6. Fit rubber seal (optional)
  7. Dryfit and pencil mark the window
  8. Clean and prime the van and window
  9. Apply sealant and stick window