Our ProMaster Camper Van Conversion – Flooring

This page covers the installation of the finished floor for our  RAM ProMaster camper van conversion.

COOCFLOverview

We decided to go with a Vinyl sheet floor. Thought about carpet, but decided it was too likely to get dirty and be hard to clean.

The Vinyl sits on top of thin plywood.

The floor is insulated with rigid polyiso insulation board.  If you are wondering whether insulation is worth the bother …

Go back to the main camper van conversion page…

Construction

From bottom to top, the floor constructing is:

  • The truck floor, which is ribbed.
  • Plywood slats to fill in the spaces between the ribs in traffic areas.
  • An inch of rigid foam board insulation.
  • A layer of quarter inch plywood
  • The Vinyl sheet floor

The insulation is bonded to the truck floor with Great Stuff polyurethane foam, and the quarter inch plywood is in turn bonded to the top of the insulation board with Great Stuff.

The Vinyl sheet floor just floats on top of the plywood.

The quarter inch plywood might seem on the thin side, and it probably is, but we are trying to minimize weight, and using 3/4 inch plywood would have added about 70 lbs. The way everything is bonded together with the foam polyurethane, the steel floor, insulation, and thin plywood act as a single unit, and the finished product seems quite stiff and strong to walk on.

 

COOCFLIMG_2874

This is the ProMaster floor before starting. Note the low spaces between the floor ribs.

 

Filling the Space Between Ribs

I filled the spaces between the floor ribs with strips of 1/4 inch plywood glued to the metal floor in order to give the insulation a flat surface to rest on.

These pictures show the filler strips going down. I only used them in the areas subject to foot traffic, not under the beds or galley. The paint cans are weights while the glue dries.

I tried a couple of things to glue them down the — I wanted something that would not require weighting.

The XXX worked pretty well for this.

 

Insulation Board

The insulation board I used is 1 inch thick polyisocyanurate rigid foam board. The brand I used has thin face sheets that appear to be made of a fiber reinforced material. Atlas RBoard is one brand that has this kind of face sheet. I think that the more normal polyiso with the reflective alum foil face sheets would also work OK — I used the ones already had on hand.

 

I used beads of Great Stuff polyurethane foam in a can to bond the insulation panels to the floor (its the orange stuff).

I used the Great Stuff Pro version, because I had it on hand, but the regular Great Stuff (I think) bonds even better.

Using Great Stuff for an adhesive might seems strange, but I’ve used it on a number of projects and it works well — its a very tenacious adhesive, and it fills voids well.

This shows the foam insulation board being weighed down with concrete pavers we had around. The weights keep the foam from expanding upward and pushing the foam board up.

I drilled out the the tiedown locations that would be located under furniture for any potential future use. This turned out to be all but two of the tiedown locations.

Water Pipe

We are going to have the fresh water tank on the passenger side just aft of the sliding door, and the galley sink is on the drivers side, so I needed to run a water supply pipe between the two. Running under the floor seemed like the most logical place for the pipe.

 

Its a little hard to see in the left picture, but there is a space between the forward and aft insulation panels just wide enough for a half inch PEX line. The PEX tubing is white and is already in the groove.

The right picture shows the groove partly filled with Great Stuff (for insulation under) with the PEX pipe being pushed into the groove.

I will probably have to use a SharkBite elbow fitting to connect to each end when doing the plumbing as its probably to tight to get the crimper in.

Plywood Floor

I used 1/4 inch laun plywood over the insulation board. This spreads out the load of walking on the floor to enough area that the underlying insulation board does not dent when you jump on it.

 

The left pictures shows the plywood sheet being trimmed to fit the wheel wells and the front step area. I positioned the plywood so that the seams did not coincide with the insulation board seams.

The right picture shows the Great stuff over the insulation board to bond the plywood and the insulation board together.

installing insulated plywood floor

The picture above shows the plywood weighted down while the Great Stuff is curing.

Edge Strips

I put in wood edge strips to support the edge of the plywood at the two doors, to keep the edge of the insulation from being compressed down.

The left picture shows how the plywood overhangs the insulation board by about an inch to allow room for the edge board that supports the edge of the plywood. The edge board is sitting on the plywood just above. I put a bit of Great Stuff in before installing the edge board just to bond things together.

The right picture shows the edge board being tapped into position.

There will eventually be a metal molding to protect the edge of the Vinyl.

Vinyl Floor

We decided on a Vinyl floor because it would be easy to clean.

I cut the Vinyl to 72 inches wide and 122 inches long and then unrolled it in the van.

Trimmed the edges by just pushing it into the corners and edges and cutting with a utility knife — leaving about 1/8 inch for expansion — this goes surprisingly fast.

After reading the instructions on the adhesive can and talking to the floor store person, we decided not to glue the floor down, but just let if float. The adhesive says that repeated freeze thaw events and temperatures below 10F may damage it (not sure if the “it” is the adhesive or the floor), and the floor store people said that they have some difficulties with RVs that live outside and some types of Vinyl floor cracking with the heating and cooling cycles. According to the floor store, the floating installation is fine and they do it quite a bit.

Will probably do something later to finish the step up to the seats at the front (or not).

Cost, Weight and Time

The time to do the floor was about 2 1/4 days — these are lazy old retired guy days, so you might do much better.

 

Item Cost ($) Weight (lb)
3 sheet luan plywood $36 37
2 sheets 1 inch polyiso insulation $38 16
Vinyl Floor $110 26
Great Stuff Foam (about 1.5 of the Pro size cans) $20 1?
Total $204 96 lbs

The weights are based on the actual square footage used, while the costs are based on the materials bought and include waste.

Go back to the main camper van conversion page…

Gary

July 21, 2014

Questions? Comments?

21 Comments

  1. Hi, I am about to do the floor my van and planned on using 1/2″ plywood to over the insulation so I have something to bolt down the bed and build a countertop, shelves, etc. I like your idea of 1/4″ plywood but I don’t know how I would do that and bolt down bed and other stuff. Do you have any pictures of how you bolted down the bed? Thank you for this site. Excellent resource.

  2. I’m looking to do my flooring with the same approach as you’ve outlined here, had just a couple questions:

    I still couldn’t bring myself to use the 1/4″, so I purchased 15/32″ BCX plywood (sanded finished but not as smooth as the laun or birch), questions:

    1. Do you think the 15/32″ would be prone to warp from temp/humidity changes, which would pull away from the adhesive? I imagine the 1/4″ is flexible enough to eliminate this risk, but I worry about the thicker stuff, given that the plywood already has some warp in it from the store (tough to get a flat piece).

    2. Has the laun continued to hold up? No compression of the rigid foam under load? No warping or pulling from the adhesive? This will be a full time home for me, so I certainly want this floor lasting.

    Thanks!!

    Mike

    • Hi Mike,

      Not sure on the greater tendency to warp more strongly — I’d be inclined to think it would be OK. You do have stuff (furniture, beds, ..) weighting down the plywood that should help. If you could figure out a way attach the edges together where two sheets of plywood meet, that might also help — maybe thin sheet metal at the edges to splice them together? You could try biscuits, but half inch is pretty thin for biscuits.

      I realize you have bought the plywood, and this might not be practical, but you might consider using MDO (Medium Density Overlay) plywoo. Its a good quality plywood with resin impregnated face sheets on each side — its very stable and water resistant — used to make things like freeway signs and chemical tanks. Its a bit pricey at about $50 per sheet. You might have to look around for it, but a couple lumber yards carry it in Bozeman. I’ve used it for various things for years and been very happy with it.

      Our floor has been fine. No warpage or other problems. But, we don’t do anything heavy duty — like carry motorcycles in back.

      Gary

  3. Hi Gary-
    Went to the hardware to get great stuff today. They told me the adhesive needed a gun for another $50. Will the other types of great stuff work? Also, can I just put a second layer of reflectix on the walls for insulation? I’ve already got some and would hate to waste it. Thanks.

  4. My Nissan NV van came with a rubber mat over the ribbed floor. I like your idea of the 1″ insulation covered with 1/4″ plywood and vinyl flooring. Do I need to remove the rubber mat and put wood strips between the floor ribs, or might a 3/8″ plywood over the insulation be stiff enough? Thanks.

    • Hi Jon,
      I think that the 3/8 plywood over 1 inch rigid insulation would probably work OK.
      Try to be careful with where you put the joints and don’t let the insulation panel joints align with the plywood joints.

      If you are carrying heavy stuff in the back (eg motorcycles) you might need a more robust floor design?

      Gary

    • Hi Jon,
      The regular Great Stuff that comes in the cans with an included plastic tube applicator is at least as good an adhesive as the “Pro” version of the Great Stuff. Having used both quite a bit, I think the regular Great Stuff might even be a little better as an adhesive (but both are excellent). The Pro stuff has some other features — I think that better fire resistance is one of them.

      The reason I use the Pro is that the applicator gun is much easier to control than the built in tube applicator on the regular GS. There is a world of difference, and if you are going to use a lot of Great Stuff, I think the Pro applicator is worth it. Try Amazon — I think I paid $35 for mine.

      If you have not used Great Stuff before, be careful. If you get it on your hands you will be wearing it for a week. If you overspray it on to parts of the van you did not want to spray, its a bear to get off. Acetone will take it off before it cures, but after cure about the only way is a scraper. Wear old clothes.

      Gary

  5. Thank you for the detailed flooring instructions. I have only one question. Did you nail/screw the plywood through the van floor? i

  6. i enjoyed your site so very much. thank you. i found you accidentally and am
    so glad i did. i found so much i could relate to. i am an
    older, single woman who has dreamed of creating a camper out of a new
    van for many years. i just purchased a ford transit cargo van, 150, 130 wb, medium roof, so clearly i could very much appreciate your story of your promaster conversion. i am SO with you – simple, airy,
    spacious and not complicated. you can shower at campgrounds; the portatoilet gets you through, and a simple, practical galley is all anyone needs.

    my son feels i should build a “U” shaped piece of furniture that works as a couch (for a whole lot of people who will NOT be in my camper! ) that would convert into a full sized bed at night with the addition of a middle piece…i feel that this will turn my lovely van/car into a “bed on wheels” and cramp my space during the day when i might want to just sit in a chair and read, and keep my labrador company. so we disagree. and things are moving
    slowly. i am grappling with how to create two comfortable beds that can
    be folded down at night and used as sofas by day. i have my galley done:
    a lovely stainless drop-in sink, with a manual hand pump system for water
    use. i have a Norcold fridge/freezer (just right for two people for three days or
    so) that is built in, with ventilation, of course. i carry a Gladiator coleman gas stove and would use it inside with windows/doors open, if caught in a rain storm and simply HAD to cook something. otherwise, i love to cook outdoors – why go camping if you plan to stay cooped up inside? i love your idea of maintaining space, openness, and keeping it simple and easy. one has to worry about the over-all weight these vans can transport, i think it wise
    not to overload and create a claustrophobic living quarter. thank you for your blog/site. i enjoyed it tremendously and would love to read more and keep track of your conversion. i am with you in spirit!

    • Hi Jean,
      Congratulations on the new van!

      The nice simple layout has really worked out well for us so far.

      My personal thought is that the bed part is more important than the seat part — that is, its really important to have good comfortable bed with a good mattress. We used to have a Coachman class B RV that had a couch that converted to a bed, but the bed was so uncomfortabe that we ended up redoing the whole interior to get a simpler layout that had a good bed.

      With the layout we have with beds on each side, we just sit in the beds with feet going into the space between. We have a few loose pillows that can be arranged to make a back cushion. For us, this works fine. The only way its not so comfortable to sit in is that its a bit high and your feet dangle rather than touching the floor. I put a couple of blocks of wood to rest feet on to help with this.
      For this last trip, we have added a removable shelf that spans between the two bunks at the back (near he back doors) — its 18 inches deep. The main reason for this was to have a place to put a cup of coffee or a plate when eating.

      Really like the idea of a stove that can be used outside — if we were doing the conversion again, I’d go that way.

      Please keep us posted on your conversion.

      Gary

  7. Gary,
    Finally I am completing the floor for our van. I really like the colors of the vinyl sheet you selected. Where did you purchase it and what is the ID number to check it out? Thanks. Your site is amazing and extremely helpful. Great work!

    David

    • Hi David,
      It was just the local floor shop in Bozeman.
      I don’t see any identifying numbers on the part of the floor that I can get to.

      Maybe just take one of the pictures down to your local floor shop?

      Gary

  8. Question – So you didn’t screw anything down to the frame with this floor setup? From what I saw it’s adhesive for wood floor joists to the metal frame, and then Great Stuff for the insulation and plywood. Is that correct? Do you plan for the furniture being bolted down to the frame to hold the floor in place? Or do you think the adhesive was enough on it’s own.

    Thanks for such a great site, by the way! I’m just starting my Transit conversion and would be lost without you and a few others I’ve found.

    • Hi,
      The floor is held in place with bonding only and this has worked out fine — no problems at all. It might be a different story if were carrying something that put more load on the floor — maybe motorcycles?

      The furniture (beds and gally) are bolted down through the vans metal floor with plates underneath to keep the bolts from pulling through the floor. The galley is also anchored to the body side panel frames near the top of the galley. I tried to size these to stay in place in a crash.

      Gary

  9. What glue did you use for glueing the plywood strips (slats) to the metal floor on the first part of the floor installation? You mentioned XXX. What is XXX?
    Thanks.

  10. I am doing a very similar flooring and thought maybe the 1″ of rigid foam board and 1/4″ of plywood wouldnt be enough support (considered 1/2″) and was contemplating breaking up the insulation into segments with support boards between them. But it looks like you went without any additional support. Do you find that the rigid foam is plenty strong to support walking around/cabinetry/etc. Are you still content with the 1/4″ plywood?

    Thanks a bunch and I love the site, it’ an amazing resource.

    • Hi Justin,
      I had the same fear, but decided to try the 1/4 inch to keep the floor weight down.
      It has been fine so far — don’t notice any soft spots or cracking of the plywood or places that appear to be lower.
      I don’t really know how to determine if the insulation has been compressed at all, but I don’t see any evidence of this.

      This is just with foot (human and big dog) traffic — might be different if you plan to carry some heavy loads?

      Gary

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