DIY Van Conversion | Walls + Ceiling

Van Conversion

I am not a van conversion professional or professional handyman. This is a documentation of my experience and you should make your own decisions on how to build your own van, and seek professional guidance if you are unsure. This blog post also contains affiliate links, so if you click a product link and buy from the merchant, I will receive a commission fee. The price you pay remains the same, affiliate link or not. Buying through my product links is the best way to say thanks if this blog post was at all helpful to you.

Materials Needed:
  • Cross Nuts (Buy on Amazon)
    • These secure into the existing holes in the walls of the Promaster and give you a threaded rivet to attach things to via a bolt, instead of having to drill new holes into the metal.
  • Cross Nut Tool (Buy on Amazon)
  • Loctite (Buy on Amazon)
  • 10-32 All Rod (Buy on Amazon)
  • 10-32 bolts
  • 3/4″ Self Tapping Lath Screws (Buy on Amazon)
  • 1/2″ Lath Screws (Buy on Amazon)
  • 1 7/16 Wood to Metal Self Tapping Screws (Buy on Amazon)
  • 1/4″ Ply, 1/2″ Ply, 3/4″ Ply
  • 1x3s, 1x6s
  • Climbing Rope
  • Clothing Hooks (Buy on Amazon)

Cross Nuts

Essentially a threaded rivet, cross nuts can be a great tool for a van conversion, and they can save you from having to drill into your van, as they fit into the pre-existing holes (at least in the Promaster and Transit). It also would allow you to remove/reattach anything using them, which was nice for some of the wall pieces I used. I also have pretty easy access to the inner door mechanics should something in their break since I used these for the doors. That said, it is faster to just put a self-tapping screw through and into the rib of the van, so where it made sense I did that as well. I thought the combo worked out nicely.

Here is the cross nut once installed, from the inside of the van rib:

And here it is on the outside, where you can now run a 10/32 bolt into.


I used 1x3s attached to the ribs of the ceiling with cross nuts. I used flat-headed 10-32 bolts (so that they lay flush/countersunk in the 1×3). I could not get the 1×3 to flex the full curvature of the roof so I cut them to half-length. I also made shallow scores with a table saw along the topside of the 1x3s to allow additional flexibility. I used existing holes in the ribs of the van where available but had to drill a couple of extra holes for the cross nuts. Once all the cross nuts were in place I cut the 10-32 allrod into 1″ pieces, twisted them into the cross nuts, and drew some sharpie ink onto the ends of them. I then pressed the 1x3s into the allrod to mark where the holes should be. I drilled the holes for the bolts on the marks and attached them with Loctite. I did this before adding the insulation. Here is a how to on installing the cross nuts with a tool.

I then used 1/4 ply screwed into the furring strips with 1/2″ Lath screws.

I had to use additional strips on the drivers’ side to finish, but these are largely hidden behind the cabinetry.

For the awkward ~45 degree corners of the van, I used additional 1x3s drilled into the ribs here. I filled the gaps with more foam board, and then on top of that I added 3 2x.5″s that I ripped off a 2×6″. I also cut out a spot for the existing light above the sliding door on the passengers’ side.

For the ceiling, since I could not do the whole thing in one piece, I had one big seam across the van horizontally. I ripped a thin trim piece with 45 degree angles out of a 1×6″

I secured it by spraying some foam board adhesive above the plywood, and then wood gluing and bracing the trim piece up.

To finish the 45 degree corners I used some weathered grey 1×6 wood on top of the strips I had created to finish it off. I also kept the existing light above the sliding door.


Each section of wall ended up being a little bit different for me. I’ll go through it in the order I put them up.

First up was this 1/2″ ply in the right of this photo. I attached it using cross nuts and bolts directly to the ribs and wall of the van. This section of wall needs to be strong enough to mount the heavy inverter and will be drilled into to support the countertop. Because of this I wanted it to be thicker and secure, and the 1/4″ on furring strips I used above would not have done that. All the cross nut holes were pre-existing here. Using bolts with large washers to attach this piece allowed me to oversize the drill hole and be less precise which was nice compared to the furring strips on the ceiling.

I drilled holes in this piece for wiring to run out of and took it on and off many times, which was made possible by the cross nuts.

Moving to the lower rear section of wall in the van – I used 3/4″ sheets cut to the height of the bed and scribed out the wheel wells. These were heavy, but I chose 3/4″ for this part of the wall because it was going to support the ends of the bed frame, and also be used structurally for other things later on. This is the only section of wall that I used 3/4″ ply on. Once these pieces were complete I used the wood to metal screws to attach it to the van ribs.

I then used 1x3s as firring strips, drilling them into the horizontal ribs using Wood to Metal Screws. I had to cut back some of the insulation for the tops of the 1x3s to fit without bending. I also used a strip of 1/2″ ply on the large rib in the center since it bulges out further than anything else, and is curved.

To finish these walls I used 1/4″ ply.


I used 1/2″ ply, attached with cross nuts again for the lower sections of the door, which are straight and have pre-existing holes for cross nuts. I especially wanted 1/2″ on the rear doors here so I could attach things to something sturdy.

The rear doors are 1/2″ ply attached via cross nuts on the bottom, and 1/4″ strips (cut out of all my leftovers) above. I attached climbing bolts to the right door so we can organize climbing gear when the gear drawer is pulled out. I also attached a shoe net to the left door to hold our mountain biking shoes, boot warmers, etc.

The sliding door was finished with a 1/4″ sheet and a whiteboard. Drilled directly into the metal using 3/4″ self tapping lath screws.

Above The Sliding Door

I didn’t document this well but will do my best to explain here. Above the sliding door, I attached a 2×2 in the deeper area above the rib to create a more level surface with that rib. I then screwed down a 1/2″ sheet directly to the 2×2 and the metal rib of the van here, until it hit the curve starting near the passenger seat. For the curve, I used a series of small  1/2″ pieces drilled directly to the van. I then used a piece of 1/4″ over the entire thing to clean it up. I finished it with some hooks for drying clothes and trimmed it with climbing rope. Here is the result.


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