Insulating from below

Has anyone insulated the floor from below? I don’t have a high top and I want all my headroom, polyiso from below seems to be the best solution. I know it’s potentially vulnerable to road debris and squirrels but I don’t see it being done much, there is only one video I found on youtube with it being used. Is there a nightmare story I am just not hearing?


Hmmm… in all of the van life videos I’ve ever watched, I’ve not once seen, or heard, of anyone doing that. Do you have a link to that video? I’d love to see it!

Insulating confuses me a bit because I’ve heard people staunchly advocate it and others who say it’s overrated. I’m more inclined to insulate against the heat than I am against the cold.

Mice can be a big problem in van life. If nothing else, that would be my biggest concern since I plan to be very rural most of the time.

I get nervous when folks put their water tanks and/or propane under the van. That lowers their clearance and how do they not get damaged and punctured?

Adding a layer of dynomat or truckbed liner under your floor is a good option if room is a concern of yours. I cut and added some to the inside of my wheel-wells to cut down on vibration and temperature.

I painted the entire floor inside with truckbed liner and added a can of Great Stuff under the sub-floor before I put it down. Filled in all of the empty spaces, waterproofed, and insulated it like crazy.

I have also mounted my water tanks up under the floor but I live in Los Angeles, where weather isn’t a thing. Having the extra room inside is worth the risk to them getting busted, which hasn’t happened, yet. Anything can be replaced or done better

Is this the video that you found on YouTube? I’ve been trying to find more information for you but, I agree, this video isn’t much help.

After some searching, the only other info I found was this conversation and this one that at least talk about whether or not it’s a good idea.

Yep that was the video that got me going on it.

Well, you may just have to be the pioneer that does it and educates other van lifers on either the benefits received - or lack of necessity for - insulating the undercarriage.

Not being an expert by any means, my first thought is, “Yeah, I can see how that would help.” But the bigger part of me thinks it would be:

  1. A rodent/pest invitation.
  2. A possible fire hazard (depending on the type of insulation I guess).
  3. An unnecessary expense given that auto makers don’t do it already. Are there things under there that need the space to breathe to keep cool?

At any rate, I hope you’ll keep us informed on what you choose to do and the results!


I think I’d stick to the original type thick felt pad that they use under the carpet in passenger vans.


"With age and experience comes wisdom and knowledge." ~ RoadWise