In this article I will cover how I insulated the floor in my Ram ProMaster van. I used 3/4″ RMax Polyiso rigid foam board for my insulation. However, I had a lot of trouble finding it in southern California, none of the big box stores carried it.

I ended up being able to custom order some through J&B Materials. They were super helpful, give them a call for any building supplies if you are in the area. 

There are tons of hot takes in forums, articles, and on YouTube about the best insulation to use for the floor in a van. I’m not here to tell you what’s best, you can choose whatever you feel like works out best for your situation. There are a lot of good options to choose from – Polyiso, sprayfoam, minicell, etc. Or, skip the insulation altogether, drop in a quick subfloor, and use some heavy rugs.

I personally went with the Polyiso/grid solution because I didn’t want to drill holes into the floor of my van. The 1×2’s, along with the tie down threads, will allow for me to attach the subfloor securely, without creating new holes.

Materials/Tools Required

3/4″ RMax Polyiso Rigid Foam Board Insulation (I used 3 sheets, you can get away with 2 if the entire sheet is in good condition)
Jigsaw (or utility knife)
3M Contact Adhesive
Sikaflex 221 Sealant
Rust-Oleum Primer
Por 15 Top Coat Spray Paint
Reflectix Tape
Loctite Construction Adhesive
Foam Brushes
Simple Green Cleaner
M8X1.25 screws (for tie down threads)
Dewalt Safety Goggles
Driver Drill

Ram ProMaster Van Floor Insulation Steps

The flooring solution will all be centered around a grid of 1×2’s, so you’ll want to draw up a diagram of where you want your 1×2’s to sit in the van. The 1×2’s will be adhered to the floor, no screws will be going into the existing floor. We will be using the existing tie-down threads to secure the subfloor, as well as putting screws from the top layer down into the 1×2’s.

The insulation and sub floor are tied very closely together, so you’ll want to have your subfloor pieces cutout and ready to use for weighting down the adhesive overnight.

1] Create a grid with 1×2’s. This requires lot of measuring, patience, and cutting.

2] Cut the Polyiso to fit inside the grid. Make sure everything fits nice, but allow some room for the wood to flex.

3] Prime all of your wood with a mold/mildew resistant primer. Wait for the paint to dry.

4] Remove everything, remove the tie downs in the floor, clean the floor with Simple Green, and fill any holes with Sikaflex. If you will not be using the tie down threads at all, put a placeholder screw in the hole, or fill the hole with Sikaflex so water does not get into the van from underneath.

5] Put all of the 1×2’s and polyiso back into their spots.

6] Starting from the back, begin adhering the 1×2’s to the van floor by using the Loctite construction adhesive. Place weights on the 1×2’s. Continue going piece by piece until you get to your first seam. Use the 3M adhesive to put the polyiso in all of the voids, before the first seam.

The trick to the 3M adhesive is to spray it first on both the van and the polyiso, let it set for a few minutes until it’s tacky, and then place the polyiso. If you don’t let the adhesive sit, it will not cure/adhere the materials correctly.

Place your first piece of subfloor on top of the 1×2’s and polyiso, add weights on top.

7] Repeat step 6 for the rest of the pieces, go seam by seam until your subfloor is sitting in place with weights on top of everything. Let this sit overnight to ensure that everything has adhered to the van floor.

8] Sleep

9] Remove all of the weights and subfloor pieces. Verify the polyiso and 1×2’s are installed correctly. Give the 1×2’s a good yank, these should not move at all.

10] Spray any small voids with Great Stuff.

11] Tape off all of the seams with Reflectix Tape.

12] Take pictures and mark where all of your 1×2’s are so you can easily put screws into the wood during the subfloor installation.

In the next article, we’ll finish installing the subfloor.

In this article I cover the installation of a CR Laurence window for my ProMaster passenger sliding cargo door. I absolutely love the look of these windows, but I really wish CR Laurence would include a template with these windows so you can be a little more confident with your cuts.

If you’re installing this window, measure 1000 times, cut once. After all the measuring and convincing yourself that putting a giant hole in your van is a good decision, cutting the hole and fitting the window is a breeze, just take your time.

Materials/Tools Required

C.R. Laurence FW3965R Promaster Passengers Sliding Door Window
Por 15 Top Coat Spray Paint
Bosch T118G Jigsaw Blades
Driver Drill
Foam Brushes
Simple Green Cleaner
Safety Goggles

ProMaster CR Laurence Window Installation Steps

1] Create a template for cutting out the hole. Use the cardboard from the box the window came in. In the video, I show one way, which is to use the frame and trace on the inside onto the cardboard. It helps to create a frame with 1×2’s, or have several people holding the metal frame, so that it doesn’t move at all.

Another way to create a template is to get some brown kraft paper and cut it roughly the same size as the cutout. Put the window on the ground, with the frame sticking up towards you. Place the brown paper on it (you will need to cut a hole where the vent lock adjustment is), and then basically color around the entire frame using a pencil. You should end up with a thicker/dark line around the edge, you can cut the paper out from here and trace that onto a piece of cardboard.

2] Place your template on the inside of the sliding door and center it the best you can. Get it taped up, again make sure it’s center. Using a pencil, trace around the template.

3] Using an 1/8″ drill bit, put two holes through the template, into the van door. You will use these holes to place the template in the exact same spot on the outside of the van to do another round of verifying the placement.

4] Remove the template. Put a drill bit in each of the holes. Put the template on the outside of the van, using the drill bits to hold up the template. Measure from the top to make sure the template is level. If all looks good, move on. If not, attempt to get the template square.

5] From the inside of the van, drill holes around the corners using a small drill bit. I used an 1/8″ bit.

6] On the outside of the van, connect the dots from one corner to another, using a marker and a straight edge.

7] Put tape around your cutout template to help avoid scratching the van with your jigsaw. You can also place tape on the bottom of the feet of your jigsaw .

8] Put a few larger starter holes in the cutout area with a drill so the jigsaw blade will fit. Cut out the giant hole in your van using a jigsaw. Go slow and take your time. Make sure you are wearing safety goggles. It’s helpful to tape up the pieces you’ve cut to help it from bouncing around.

9] Remove the piece that you cutout. Use safety gloves to handle the metal.

10] File down the edge of the cutout. Test fit your window. If the window does not fit, file some more or use your jigsaw if a lot needs to come off, but be careful as the metal will want to bend.

11] Clean the door with simple green. Paint the edges with Por-15. The foam brushes help with this process. Wait for the paint to dry.

12] Place your window in the hole, make sure the window sits all the way in.

13] Have somebody hold the window from the outside as you get the frame set on the inside.

14] Using a drill, start installing screws into the frame. Make sure the torque is low! The screws will strip if you tighten them too hard with a drill. You’re better off just hand tightening everything after you get the screw started with a drill. I did not pre-drill holes. The window will suck in nice and tight, you’ll be able to tell when you should stop tightening.

15] Using a hose, do a spray test on the window. From the inside, check to make sure nothing is leaking around the window.

Good luck and let me know if you have questions. I’ll be moving onto floor insulation and installing a subfloor in the van, so stay tuned.

In this article I cover the MaxxFan Deluxe installation for my ProMaster. We needed one of these to suck Winnie’s farts right out of the van! Just a note, I bought the roof vent adapter that Hein from DIYVan sells, but realized that I didn’t need it for the spot I was going to install the vent. If you are going to install your vent towards the back of the van, I highly recommend purchasing that adapter so you get a nice flush mount.

Once you get over the fact that you’re cutting a hole in your new van, this project is EZ PZ. All the materials I used are listed below.

Materials/Tools Required

MaxxFan Deluxe w/ Remote
Butyl Tape
Dicor Lap Sealant
Por 15 Top Coat Spray Paint
Bosch T118G Jigsaw Blades
Foam Brushes
Driver Drill
Simple Green Cleaner
Safety Goggles
Mold/Mildew Resistant Primer
Metal File
1×2’s

MaxxFan Deluxe Installation Steps

Before installing the fan, decide if you want to create a frame for underneath or if you are just going to screw straight into the sheet metal. I chose to create a frame with 1×2’s so that the screws could suck into something. I painted the 1×2’s with a mold/mildew resistant primer because they will be attached directly to the van metal.

1] Figure out where you’re going to install your fan and find the center point.

2] Trace a template onto the roof of where you need to cut out. You can use the frame they give you as a guide, or the adapter from DIYVan if you purchased one.

3] Put tape around your template so that your jigsaw does not scratch up the roof of your van while you are cutting. It can also help to put tape on the feet of your jigsaw.

4] Put a box or something underneath where you are about to cut so that you can catch all of the metal shavings. Use a magnet or shop van on the roof as well, so you can prevent the shavings from going everywhere and rusting in the future.

5] Cut out your hole with the jigsaw. Make sure to use jigsaw blades made specifically for cutting thin metal.

6] File down the edges and make sure the frame fits.

7] Paint the edges with Por-15. I think it helps to use the foambrush. Wait for the paint to dry.

8] Put butyl tape on the bottom of the frame, on all 4 sides.

9] Place frame into the hole in your van. Make sure the silver tabs are on the passenger and driver side, this is where you will screw the fan into. Push down so that the butyl tape is solid against the roof.

10] *OPTIONAL* Clamp your 1×2’s inside the van, around the hole in the roof.

11] Pre-drill holes from the top of the frame, down into the 1×2’s

12] Using the screws provided, attach the frame to the roof. Do not use too high of a torque setting if you are using a drill. Hand tighten these as the frame is only plastic and will crack with too much torque.

13] Put lap sealant on all of the edges and over the screws. Wait for it to settle and dry.

14] Drop the fan in, make sure the wires go in first.

15] Using the screws provides, attach the fan to the frame. You may have to push down on the fan to get the holes to line up with the frame.

16] Clean up all of the metal shavings. If you don’t, you will end up with rust spots everywhere!

17] Spray water around your fan to make sure that all of your cracks/holes are sealed up.

Good luck and let me know if you have questions. The next project I’ll be tackling is installing a CR Laurence window in the passenger sliding door.