How to Build a Conversion Van
Building my own conversion van has been the answer to replacing my aging Roadtrek, Class B Motorhome. I had eleven years of terrific enjoyment with the RV, but felt it was time to replace it. When I looked into purchasing a new one, I was astounded by the price which had doubled over the eleven years.
It was then that I decided to build my own conversion van.
I did a lot of research on available vans, visited many car dealers to check the fit of the different brands to my personal needs, compared prices and finally settled on the Dodge ProMaster Van
It was a little intimidating at first looking at the wide open interior and wondering how I was going to accomplish everything I want to do with it. Fortunately, I have a talent for looking at things and seeing how they can come together to create what I want. I also have a lot of woodworking and mechanical experience.
The first thing I had to do was analyze what I wanted in my new conversion van. I had the advantage of eleven years with the Roadtrek to know specifics I was looking for in the new one. I did a comparison of the two vehicles and made some decisions.
In making my decisions, I wanted something I could stand up in, was economical and was under the 8-foot-high restriction that my homeowner's association decided to impose after 10 years of having my Roadtrek.
You need to understand that I am only 5'4" tall and usually travel alone, so that was influential in my decision process.
12 to 15 mpg
15 to 25 mpg
Interior Length (behind driver's seat)
2 swivel, one fixed
1 king-size or 2 narrow singles
1 twin-size proposed
While waiting for delivery of my knew van, I drew up tentative blueprints with the items I felt I wanted. Once I had the van, I made a more specific blueprint to give to the electrician who was going to handle all those details. As you see in the opening photo, I put blue painter's tape on the floor and walls so he could visually see where things were going to be.
There was some modification to the blueprint as we went along.
The biggest thing was, no side windows. I was not able to get any windows that fit the ProMaster, and custom-made ones were just too expensive. Hopefully, the in-out ceiling fan will be enough for good air circulation.
After discussing my electrical needs and wants with the electronics technician, we decided to install a charger/inverter and a maintenance-free house battery. Since the battery was going to be within the confines of the interior van under the foot of the bed, it was essential to have one that would not be giving off vapors.
The charger/inverter was chosen so that the battery would charge both while driving and while plugged into a A/C land line. The inverter was a full sine wave model so computerized electronics would function, such as my induction stove top unit which plugs into an outlet.
I chose a marine refrigerator which runs on A/C or D/C but not propane. It has a built-in inverter to automatically switch currents and was wired directly to the battery through a 12 volt-only plug-in outlet.
Now that all the electrical was done, it was time to insulate the interior. I didn't have to worry about the floor, because I had a factory-installed, hard-composite wooden floor put in when I order the van.
I started with the ceiling adhering Reflectix Insulation as a moisture barrier for the outer walls. I found it at Loews, as well as, the R-tech rigid insulation I used over it. Unfortunately, it was 95 degrees for the first 4 days I worked on it, and I had used a spray adhesive that just wouldn't hold. I even tried Gorilla Tape, and the glue from that just kept melting with the heat.
I covered the Reflectix with R-Tech rigid foam board with the reflective side facing into the interior. The way it fit between the ribs and edges of the ceiling, it helped hold things sort of in place. I also propped it up with the frame I had made for the bathroom. That really helped as a temporary fix.
Eventually, this would be enclosed with Polywall, a non-absorbent, easy to clean, recycled-plastic wall covering which would act as the final moisture barrier. I decided to wait to put this up until after I had cabinets in place.
The Polywall, which I also found at Loews, is very flexible and cuts easily with a blade or scissors. It is great for the walls and curves, but pretty tricky to put up on the ceiling. I'll talk about this more later.
As I look back at it now, I should have done the Polywall before putting anything else in. That way the ceiling would have been complete. The problem was, it takes two people to put it up. It is so flexible that it is impossible for one person to handle a 4 x 8 sheet alone, and at the time, I didn't have the extra help available.
As a result I am still dealing with finishing the insides of cabinets which would have been all done if I had covered the whole ceiling at once. Oh well, it has been quite a learning experience.
I also put a layer of Reflectix against the outer walls. It was still very hot, so I had the same problem with the adhesive.
I covered it with denim 100% recycled cotton insulation which I found at Loews. It is a great sound-proofing material, good insulator, has no fiberglass to irritate your skin, and no harmful chemicals in it.
I especially liked it because you could tear it to size and stuff it in small spaces where needed.
Of course my spray adhesive still only held part of the time. It was interesting. Anything I did before 9 AM stuck. Anything after that was found on the floor by evening
The next step was to cover the denim with another layer of Reflectix to act as a moisture barrier from the interior environment. Fortunately, the unseasonably hot weather had cooled down so that I was able to completely seal in the three layers of insulation using Gorilla Tape.
I also applied a wooden board over the top edge of the insulation. This helped hold it, but it will also be part of the framing that I screw my overhead cabinets into.
I also had to put a 1 x 3 board on the ceiling to give the cabinet a second point of support. This was set back about 1 inch from the front of the cabinet. (not shown here)
I also had to put a 1 x 3 board on the ceiling to give the cabinet a second point of support. This was set back about 1 inch from the front of the cabinet.
I followed the same procedure for the three doors, except I only did the first two layers. I figure that the cover panel that comes with the van acts as the interior moisture barrier.
I was careful to not place any denim insulation where it would interfere with the mechanical workings of the door.
Walls and Ceilings
I used an 1/8 inch thick, flexible, 4 x 8 sheets of white recycled plastic that I got at Loews. They are moisture resistance, cut with scissors or a utility knife, clean very easily, and are non-toxic.
The flexibility had the advantage that you could easily shape then to the contours of the van. The dis-advantage was that it was difficult to handle them alone, especially on the ceiling. My son gave me a hand with that.
They were attached to the ribs of the van using 1/4 inch, sheet-metal screws. After I had struggled with a few when putting up the walls, a man at Ace Hardware told me to put a small amount of 3&1 Oil on the screw tips first. It worked like a charm. I just wish I had known that earlier, but now I do.
I had an "In-Out" ceiling fan put in right over the bed. It gives great ventilation when parked, but I am finding that a second one up front behind the seats would be a good idea. I'll probably just have one without a fan put in, since the other one has a strong motor and would do all the work.
The only areas left to insulate were the wheel wells. To cut down on road noise, I applied two layers of Ensolite IUO peel and stick sheets and then covered them with Reflectix, sealed with Gorilla Tape.
It was pretty tricky doing the Ensolite working around curved surface with the self-adhesive backing, but I found that tucks I made could easily be cut away with scissors to make it smoother. I have to admit, I only took pictures after I covered it with the Reflectix since that looked much neater.
That is a piece of the Ensolite laying in front of the wheel well.
Well, that covers all the insulation processes. Have I discouraged you yet?
Are you ready to start converting your own van?
Overhead cabinets were next on my list of things to do. I started with the long one next to the side door. I did that one first, because the other ones were dependent on my getting the bathroom space framed out and squared.
In researching building cabinets, I decided to go with framing using 1 x 2's, and joining them using pocket screws. This way I had light-weight cabinets with strong joints.
I was so glad I did the pocket screws because there were times when I unscrewed them, especially when it came to the bathroom structure.
The ends were capped with 1/4 inch Baltic (Russian) Birch plywood which is a cabinet-grade plywood that is very stable.
I had all ready put up the side board that the cabinets would be screwed into, and the 1 x 3 inch board on the ceiling to give the cabinet a second point of support.
I added a 1 x 2 board on the top of the cabinet just behind the face board. I put it flat so it could be screwed into the ceiling board. It was just the right amount of spacing to level the cabinet and make up for the slight curve in the ceiling.
I put two angle brackets onto the vertical supports in the middle for extra strength.
Once installed, I screwed 1/2 inch MDF board on the bottom on the cabinet . I decided to put it on the exterior rather than in the interior of the cabinet so that I had the extra two inches of storage space it gave me.
It also provided for a barrier to prevent things from sliding off the shelf.
Inverter Remote and Smoke Detector
At the end of the overhead cabinet near the sliding door, I placed the remote switch for the inverter. I recessed it into the cabinet side.
Next to it, I hung the smoke detector. It is on the opposite side of the van from the stove so hopefully cooking won't trigger it.
I used 1/2 inch Baltic birch for the doors and attached them with piano hinges.
For the overhead doors, I considered the hinges that keep the door open but decided not to get them. They told me at Loews that they didn't have them anymore because they were recalled.
My RV dealer told me that a lot of the hinges were failing and he would not recommend using them. He reminded me that years ago magnets attached to the ceiling and the door knob were the way they kept the doors open. It is a consideration, but for right now I'll just hold them up when I need to.
On several of the vertical doors, I used magnetic baby locks along with spring roller clamps. Having both would ensure that a door would not swing open while driving, but would also stay closed and unlocked while parked.
There is a switch on the lock which enables you to keep it locked or unlocked.
A strong magnet comes with the lock so you can undo it from the outside of the door.
When it is locked, the magnet is placed on the outside of the door and releases the lock.
You want to be sure to keep the magnet in a handy, but safe place,
When the door is locked, nothing is going to unlock it except a magnet.
The Bed Frame
I decided to put the bed frame in early so I could test to be sure I had enough room between the bed mattress and over head. I'm short so it was fine.
I used 2 x 4 studs to frame out the bed platform. I made it twin sized in width which was about 40 inches.
In the ProMaster, the interior width is 6 feet so it was perfect for putting the bed across the back of the van.
I built the frame 19 inches up so there would a lot of high storage area for me, as well as, adequate space for the electrical units at the foot of the bed.
I had to compensate for the wheel wells under both ends, but that was easy enough.
The corners in the back were screwed into the medal frame.
The front ones were just moved out past the wells and secured to the bed frame and floor to keep them vertical.
My next project was to get the walls of the bathroom in, square it up and get the side panels varnished and attached to the frame. I did this next, since I could not do the driver's side overhead cabinets or sink counter until that was done.
I had to put it together in the van, a piece at a time, because of the height and width of it.
Attaching the Bathroom Unit to the Van Wall and Ceiling
I started with the left side frame attached to the top and bottom back rails.
I screwed the horizontal board of the upper back frame to the wallboard I had run the length of the van for the cabinets.
Once that was secure, I attached the right side frame to the back with pocket screws.
I am so thankful I used pocket joints, because that made it so easy to put it together in place.
Next I attached the front frame to the two sides. I then squared the side walls to the back frame and screwed the top rails of the sides to the ceiling board.
Side Panels and Attaching to the Floor
I squared up the vertical back frame to the floor and then attached it to the floor using chair brackets. I had to be careful with the length of the screws, because the factory-installed, composite wood floor was only 3/8 inch thick.
I used 1/4 inch Baltic Birch, cabinet-grade plywood for the walls of the bathroom. I varnished them first with two coat of Minwax Helmsman Gloss Oil-Based varnish. This was used on all wood surfaces in the van.
Once the side panels were on, I was able to square the whole unit up and attach the front of it to the floor using the chair brackets.
After a great deal of research and a recommendation from a friend familiar with composting toilets, I chose the Air Head Composting Toilet.
The toilet requires a vent with a small fan in it to keep any gases from coming into the cabin. I opted to have it installed in the floor. I had the technician who did all the electrical do the installation because:
- I was afraid to do it myself, and
It requires a continuous flow of 12 volt current.
He did put an on/off switch into the system so that if I could turn the fan off when I had the commode apart for cleaning.
To attach the toilet to the floor of the van securely, first I adhered a 1 inch-thick wooden disc to the floor. A friend had some very strong aviation glue which worked very well.
I did also screw the disc down just as an added precaution. Then I screwed the four clamps on which hold the solid waste portion of the commode and the liquid portion.
Everything easily connected simply by placing the commode into the clamps and tightening them. The liquid part is a 2 gallon container that removes easily for emptying into any toilet or dump pipe.
The solid part has peat moss and is good for about 80 uses before it has to be emptied into a black plastic bag for additional composting. The crank handle on the right stirs up the peat moss so things compost better.
The Remaining Overhead Cabinets
Now I was ready to do the remaining overhead cabinets and sink/stove counter. I made the one that would be over the stove only 9 inches high instead of 12 to ensure more space above the heat.
I added a cabinet in the bathroom, but I had to assemble that one right in place due to the limited space. Again, I was really thankful that I did pocket joints.
The Sink/Stove Cabinet
The final cabinet I made was for the sink and stove.I assembled it in place between the bed frame and the bathroom wall. I had to make adjusts as I went along to fit around the wheel well that was partially under it.
I made two roll-out drawers for it, so I would have a place for silverware and to store the induction stove top unit when not in use. You can see it fits perfectly in this picture.
The counter top is about 24 x 24 inches which I'm really glad I made.
I originally had only planned for it to be 20 inches deep, but found I could increase it once I had other structures in place.
Being this size it gives me ample room to put the induction stove-top unit on the counter while cooking.
When not cooking, it gives me handy workspace to the right of the sink.
In making the cabinet for the refrigerator, I had to be sure that the back was well vented so there would not be any overheating.
The refrigerator backs up partially to the side door opening and so I left the back completely open.
I installed a microwave on top of the refrigerator cabinet. to secure it, I drilled shallow holes in the counter top for the legs to set in.
I also strapped it down with a nylon strap that was secured to the counter top with an "L" shaped bracket that the strap was folded around.
It also provided room for the fresh-water container with a spigot to fit behind the sink.
I saved the sink cover from my old RV.
When I need more prep space, I put it on the bed and it works great as added space.
Having placed the sink counter right next to the head of the bed also has the added advantage of becoming a bedside stand at night.
It is perfect for my cell phone, glasses and Kindle.
I didn't want to have any plumbing, so I used a gray-water tank under the sink.
A tube comes from the sink drain.
The drain I chose was designed to connect easily to a tube rather than a pipe.
I placed three under-cabinet lights over the sink and the head and foot of the bed. I also added a touch LED light over the sliding door so I can easily turn it on as I come in.
I decided I only needed a small table to use for eating or setting my computer on. I was going to make a drop-leaf table to attach to the side of the refrigerator cabinet, but I found one all ready put together, including the hardware, and so I bought it.
It was $40 and was 1 inch-thick, solid oak with a piano hinge attachment and an easy-release bracket for raising and lowering it. It saved me a lot of time, was easy to install and is very sturdy.
Heating and Cooling
Most of my traveling is during moderate weather so heating and cooling is not a real problem for me.
I use a small, portable heating unit that is thermostatically controlled and throws a significant amount of heat when needed. It is quiet and does not dry the air out like the larger fan-driven propane one I had in the other RV. I also don't worry about the cat getting burned from it because of the construction of it.
I didn't put in an air conditioning because of the room it would take, the expense on installation, and power usage. Having the In-Out Fan over the foot of my bed was more than enough, although a second vent just behind the passenger seats would definitely help.
Because this size Promaster Van does not have any opening rear windows available as an option, I decided to screen in the upper half of the back door.
It not only gives great ventilation when stopped for the evening at an RV Park, but it also keeps my cat from getting out while allowing him the enjoyment of looking out at all the critters outside.
I used pet-resistant screening that won't tear if the cat gets his claws into. It is also very strong, so if he tried to climb it, it would support him. I screwed coffee-cup hooks into the wood I had installed for my curtains and then used drappery hooks to go through the screen and hook.
At the bottom I attached a board to the screen and tucked into the space between the mattress and bed board. this way it is removable, but I leave it up all the time since it really doesn't reduce my visibility out the back window.
I had tinted windows put into the van, but that still doesn't give you complete privacy.
I installed curtains across the width behind the seats.
I put a second set blocking the opening of the side, sliding door.
I also put curtains across the back window, so I am completely enclosed when they are all closed.
I got the hardware at the RV dealers and then used drapery hooks to hang the curtains.
I used bungees to hold them open while driving.
After traveling across country, I finally got a chance to order running boards for the van. They were not available through the Dodge dealer, but I found a supplier that had them specifically designed for Promasters.
I had a local auto shop install them and I am really happy I spent the extra money for them. It makes it so much easier than the fold-up, plastic stool I was using.
More To Come
I'm in the middle of doing this conversion so it is hard to take a lot of time out to write about it. I promise there is more to come, and I will try to post the progress as frequently as possible.
I just drove across country in it, and everything was perfect. I still have a few cabinet doors to make, finish outer parts of the ceiling and trim different things, but it is more comfortable and roomy than the bigger RV that I had before even though it is smaller.
Please check back to see what is next.
In the mean time, if you have any questions, opinions or personal experience you would like to share, please leave a comment below.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.