4. Floor + Carpet

The floor of our van is not hardwood, or laminated flooring.    I see many people building out their vans putting in hardwood laminate flooring, and I just don’t understand why?    You will see and walk on very little of this floor.  Most of it will be under the cabinets and in the garage area.

I also see many complain about cold floors, so they buy bath mats to put on the floor.   Others build in Radiant Heated Floors.   Installing these heated floors requires heated glycol lines under the floor.  When these lines get hot then cold, condensation will form.  That moisture from the condensation is an invitation for mold to grow under the floor.  So, I won’t do that.  Moisture and mold is our enemy.   I have done my best to design the van to avoid the enemy.  See the videos below on sealing wood against moisture!

Our floor has 1” of XPS insulation.   The one inch thickness was readily available locally.  I think you could reduce that to half an inch.  On top of the insulation is ½ of plywood.   So, this makes a thickness of 1 ½”.  If you’re really tall you may want to reduce the insulation on the floor!    XPS for Floor – Home Depot: Internet #207179253 Model #20WE Store SKU #1001965217

Preparing the floor – Before placing insulation on top of the steel van floor I recommend grinding, or sanding off any rust.   Even if there is no rust and your starting with a brand new factory fresh van I recommend paint the floor with an oil based paint.   Even with a new van there will be areas were the sheet metal is folded over, and there are spot welds.  The areas were this metal meets creates a seam.  Its best to seal this seam with a coat of oil based paint.  Doing this will protect the steel from rust, mold and mildew.  It won’t take long to do and will require just over a quart of oil based paint.   You will use this paint later.  Anytime you cut a hole in the van you need to seal the edges with this paint.

Click for Oil Based Paint at Amazon   Home Depot: Internet #205082560 Model #7797502 Store SKU #1000110298

After the paint is dry it’s time to cut cardboard templates for the floor.  These templates will be used to cut the insulation and the half inch plywood floor.   Some think a half inch plywood is thin.  Well it not!   I recommend against using ¾” its way to heavy and just not necessary.  The videos below show how to create a tracing jig, making the cardboard template, and cutting the floor insulation.

Now, a single sheet of 4 foot by 8 foot plywood will not cover the entire floor.  You will need several sheets. How you lay these out is determined by your floor plan.  You don’t want the edge or seem of the plywood right at the edge of your refrigerator or sink cabinet.

The RAM Promaster has built in threaded tie downs in the floor of the van.  These are excellent to bolt down the floor.  I used those tie downs which were along the outside edges of the floor and added riv-nuts to the floor for bolting down the middle of the floor.    See my video on installing Riv-Nuts.   Note: Anytime you drill a hole through the steel of the van, seal it by painting with some of the oil based paint!

I did not use any glue.  DO NOT GLUE DOWN YOUR FLOOR!   Why?   Well, I think you should always be planning for the worst case scenario.   What if something bad happens and you need to remove the floor.   If it’s glued down it will really be a mess.   I have seen this happen in many YouTube video’s.

Products in the video’s (Amazon affiliate links, click the text or photo):

Trim Removal tools       

Riv-nut tool    

5/16″ Rivnut     

M8 Rivnut 

M8 Bolts     

Drill stops   

Framing Square

As seen in the video – along the edges of the floor at the sliding door, and at the rear doors I placed a one inch square tube to support the floor.  This is an area that will take a great deal of impact and focused pressure as we get in and out of the van.  Square tube at  Lowes Item #215640  Model #11392  Home Depot: Internet # 204273939 Model # 802537 Store SKU # 797005    Also for trim I used Aluminum angle: Lowes Aluminum Angle 1-1/2-in W x 1-1/2-in H x 6-ft L Item #215753 Model #11357

After cutting the cardboard templates, It’s time to cut the XPS insulation.  I found the easiest way to cut this insulation is simply a utility knife.   A standard utility knife is just a little short.  After cutting through with a utility knife I followed up with a sharp thin paring knife, specifically a Victorinox paring knife.  This paring knife was relocated from the kitchen to the garage for the entire build.    After a few months I did replace it in the kitchen (before anyone noticed), these knives are excellent, sharp and easy to sharpen – Highly recommend for all types of use!  Link: https://amzn.to/485EAc9

Once the insulation is cut its time to find the bolt holes that will hold the floor in place.  Some builders don’t bolt down the floor.  I feel the floor needs to be bolted down for two reasons.  1. To keep the floor flat, and 2. To secure everything that’s bolted to the floor.

To locate the bolt holes I placed pencils in the threaded holes and pressed the sheets of insulation on top.  For a better understanding see the video.  The pencils put an impression of the insulation; I then drilled a hole through the insulation.   After fitting the insulation I cut the plywood.

When cutting both the insulation and plywood you want to leave a gap between the material and the walls of the van.  If you make them fit tight to the walls, it may squeak as you drive down the road.   Not a large gap 1/8-3/16” on all sides is enough.  Then fill the gap with Lexal caulk.    Lexal is a clear waterproof caulk that will remain pliable.  Lexal is excellent for many uses.  This is the Amazon link  but look for it at Home Depot or Lowes.  The store that carried it switched while I was building the van.  I ran a bead of caulk all the way along the floor panels.  That bead of caulk may not fully seal the floor panel, but it ensures that the insulation will not squeak.   Later when I applied the single sheet of plastic flooring I ran that up the wall.  That ensures no water/moisture gets under the floor.

Once the plywood for the floor is cut it then needs to be sealed with polyurethane or spar urethane.  Polyurethane Link  Lowes Item #85927  Model #71029000   Seal all sides of the plywood.   I applied two coats on all sides, and then one final light coat on the top after it was installed.    At this point in ==this video==    you see me pouring on a final coat.  This last coat was a 50/50 mixture of polyurethane and mineral spirits.

Removing the floor for T-Nuts – We will remove the floor one more time to install T-Nut’s in the bottom.  This will be done after designing the seats and lower cabinets.   Once the frames are created they will be bolted to the floor using riv-nuts.  By using a riv-nut and bolt through the frame and floor we will make a strong a squeak free connection.  Doing this is kind of a pain and may seem like extra work, but it provides a secure connection ensuring that the cabinets will not move when driving and hopefully will be secure in a collision.

T-Nuts 1/4-20   

Hole Saw Kit   

Steel File     

Oscillating Tool     

Once the Riv-Nuts are in place, so the cabinets and seats can be bolted down its time for the single sheet flooring.   I use a single sheet of diamond plate plastic to cover the floor.  I purchased this from Home Depot:  Internet # 301919677  Model # 03-206-W100-15

By using a single sheet I keep any water or liquid that spill from seeping into or under the floor.  We don’t want mold to grow!    Any places we cut holes through this plastic are sealed with Lexal caulk.  This stuff is excellent, clear and remains flexible and waterproof.   Also, this plastic flooring is cut so that it extends up the wall a few inches.


Drawer Slides 36″     

1/4″-20 Threaded Rod      

Bed Mattress       

IKEA Bed Rails Beam

Wood Slats         

Safety Glasses     

Installing Carpet – After the build was almost complete we installed a carpet.  The carpet fills all of the areas we walk on.  But it does not go under any cabinets.   We can easily take this carpet out for cleaning.  If we want to change the look of the van we can easily put in a new carpet, changing the color or design.  The video below shows how I cut the carpet to fit.  I also used heat seal carpet tape to stop any fraying of the carpet and increase its overall durability.

Hot Melt Seam Tape 

Hot Melt Iron      


Shag Carpet       

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