Camper Van Conversion: DIY Floor Insulation

Some of you may not know that my husband and I are in the process of converting a Sprinter van. We have been slowly making progress since January. It has been a lot of work, but we recently finished insulating our floor and thought it would be fun to touch on the insulation process! 

We wanted to share some general information about insulating the floor of a Sprinter van. Just in case you decide to throw caution to the wind and join the #vanlife community! 

Popular Floor Insulators

  1. XPS board – XPS is preferred because it is more suited to cold climates. This is the one we used. 
  1. Polyiso board – Similar to the XPS board except in cold climates Polyiso board’s R-value drops. 
  1. Spray foam – Spray foam can be used directly under the subfloor as long as it has a  high compression strength (~20 PSI+, Touch n Foam, and Foam It Green kits cure with a 30+ PSI compression strength). 

The reason we opted not to use spray foam is because of the amount of time it would take to shave the foam down flat.

Products We Used

Supports: 1” x 2” Furring Strips

Insulation: 1/2″ XPS Foam Board

Utility Knife

Great Stuff Gaps & Cracks

Camper Van Conversion: DIY Floor Insulation

Subfloor Supports (Optional)

We installed 1 x 2 furring strip supports on our floor to give us something extra to screw our cabinetry into when the time comes. We felt it added to the overall rigidity of the floor vs floating the subfloor or gluing the subfloor to the XPS board. 

Camper Van Conversion: DIY Floor Insulation

Fill Floor Ribs/Corrugation (Optional)

We HAD to keep our floor very thin (1.25 inches) because we only have 3 inches for our roof and floor or else Joey’s head would be hitting the top of the van! Because of that, we only used a 0.5 inch XPS board. 

We would recommend using 1-2 inches. Because of this, we decided to fill the ribs on our floor with insulation to be as efficient as possible. 

We used Great Stuff Gaps & Cracks to “glue” our foam boards down to the van floor, but we also used it because it would expand and fill the ribs with insulation. Since we used canned spray foam, we had to cut all of our XPS board to fit before doing this.

Be careful using canned spray foam in enclosed spaces like this. Canned spray foam NEEDS air to absorb moisture to cure.

 If there is no moisture for them to absorb, the chemicals will not cure and will off-gas. We recommend misting the XPS board and van floor VERY lightly with water to ensure it sets up properly. 

We also removed the foam board and let the foam partially set up/cure while separated and then put the board back down with weight on top.

If we could do it again, we would just use Minicell which you can order on eBay to fill these gaps. 

Cut/Install XPS board

The next step is to cut your foam board to fit your floor. If you still have the plywood floor that came with your van, you can simply trace it on your insulation board to get a perfect fit. 

Unfortunately, we did not have that, so we just used a box cutter and cut the board by hand with trial and error. 

You can tape a marker to a long leveler to create a make-shift scribe that can be used to perfectly trace the curves/shape of your van to another material (see here for a video example).

Sound off below if you have any question!

Happy travels, friends!


  • Sarah

    2 years agoReply

    Thanks for sharing. I would love to do this one day and my near-future goal is to hopefully be able to buy a van in a maximum of two years and start converting it 🙂 Just not all too sure, that I can actually do it myself as I am not very handy.

    • Tasha

      2 years agoReply

      Anyone can do it! We had no experience when we started, but things are going very well!

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