How to Install Van Insulation

Updated on February 25th, 2021

Van Insulation is very important because it helps keep the van cool when it’s hot outside and warm when it’s cold outside. We plan on using our van only for adventures and not full time so we did go slightly lighter duty on insulation than someone might if they are planning to live in their van. We also chose not to insulate the floor. Andy gave an in-depth explanation about why we didn’t insulate the floor in our Subfloor Video at around 5:30.

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Tools Needed:

• Utility Knife
• Utility Knife Blades
• Measuring Tape
• Caulk Gun
• Putty Knife

Supplies Needed:

• 3 Sheets of 4’x8’x1” XPS Foam (Extruded Polystyrene Foam)
• 10 Tubes of Loctite Power Grab Construction Adhesive
• 10 16 oz Cans of Great Stuff Expanding Foam Insulation
• 12-18 inches of ¼ inch Nylon Tubing

Measure Wall Cavities

Start with a section that has no weird things you need to cut around. You will thank us.  Measure in at least three spots, top, middle, and bottom. You will be cutting to the largest measurement and trimming where needed.  For areas that you need to cut around, such as the fuel fill, or wheel wells, you’ll want to cut each piece to a rectangle and then trim around.

Cut the Foam Sheets

Use a utility knife to cut the foam block to your measurements.  We were lucky that the sheets were 48” tall and our walls were 48” tall.  You’re going to want to cut your foam into smaller pieces (we cut ours into three per cavity) to better fit the curve of the wall.

It’s also important to trim the sides of the block so that metal ribs do not interfere with the block resting flat against the wall.  We found that cutting a 1”x ½” strip off the sides was perfect. See 1:20 in the video for a demonstration.

Install the Foam Board

You will need to use an adhesive to attach the board to the wall.  We have seen a few videos were others have used spray foam as an adhesive.  We are here to tell you: spray foam is not an adhesive.  Use adhesive. Put adhesive along any ribs on the van and then around the edges of the board.  Add a little spray foam for good measure to the edges and slap that sucker up on the wall.

Repeat from “Measure Cavity” until finished with foam board.

Spray Foaming

The easiest place to start spray foaming and get a feel for how the cans work is on the walls.  Once you move onto the ceiling it is going to be raining spray foam in your van.  Spray around the foam boards, in any cracks, and then into any of the wall ribs.  We found a little nylon tubing to be really helpful in getting every last bit of spray foam out of the containers and reaching all those cracks and crevices.

Once you’ve sprayed the foam you’ll need to wait 10-12 hours for it to cure before you can shave off any excess.

Trim Spray Foam

Spray foam has a way way of getting everywhere.  The best rule of thumb is to let it dry before trying to remove it from hard surfaces.  It will just pop off with a putty knife or screw driver.

For the areas where you need to trim you are going to want a knife with an offset handle, it will save your knuckles.  Andy chose to use an old Sawzall blade that he bent and added some tape to the handle.  No need to buy an extra tool when you can fashion something from what’s in the garage! 

A Couple More Important Tips

It is really really important that you install any wiring that you might want to run through the ribs befor you fill them spray foam. We have chosen not to run our wiring through the ribs because we like the idea of being able to have access to the wiring if something goes wrong. The plan is to put box shaped trim panel where the wall and ceiling meet and hiding the wiring in there.

Also, we recommend that you wait to fill all of the ribs until you have installed the initial framing for your bed and cabinets.  You will see in the final clip of the video when Andy is shaving the foam off we have already installed the supports on the walls. This was because we wanted to thru-bolt where we could and the hollow ribs allowed us to put nuts on the back side.

Estimated Active Time:  6 hours

Estimated Total Time:  18-24 hours

We’d love to answer your questions!  Comment below and we’ll help!

Previous step: Van Subfloor

Next step: Van Framing

For more posts related to the van build check out our Van Build Page.