Sound Dampening, Insulation and Windows

In this post we’ll cover some of the initial steps in our Sprinter conversion, from back in March when we were struggling with freezing conditions that made it difficult to want to be outside. This post covers sound dampening, insulation and windows.

Sound Dampening:

When driving an empty Sprinter van, you can get quite a lot or road noise and while we wanted to eliminate as much of it as possible, we didn’t want to spend too much. A lot of people seem to spend a fortune on sound dampening! Our thought was that the majority of the noise comes from the wheel wells, the doors, the large, thin sheet metal areas, and the area above the drivers cabin (behind the grey overhead cover). The sound dampening material isn’t cheap and we thought that the furniture we built into the van would act as additional sound dampener. In the end, we opted to use RattleTrap.

When driving an empty Sprinter van, you can get quite a lot of road noise and while while we wanted to eliminate as much of it as possible, we didn’t want to spend too much. Further, our thought was that the furniture we built into the van would act as additional sound dampener and we would focus on using the sound dampener on the areas that produce the majority of the noise; wheel wells, axles, doors, and the large, thin sheet metal areas, as well as the area above the drivers cabin (behind the grey overhead cover). In the end, we opted to use FatMat RattleTrap.

Materials Needed:
  • 25 sq ft 80 mil FatMat RattleTrap (Amazon)
  • Small wooden roller (Came with the RattleTrap)
  • Degreaser/Cleaner
  • Blow dryer or heat gun if the weather is cold
  • Razor Blade

We bought 5 sheets of RattleTrap with the intention of using it as follows:

  • 2 sheets for the wheel wells
  • 1 sheet underneath driver and passenger foot area
  • 2 sheets for  the sliding door, and sheet metal areas above rear wheel wells

The van was pretty dirty when we first got it and despite cleaning it out, the wheel wells had some leftover gunk on them. We used some degreaser to make sure the areas that we’d be applying RattleTrap to were entirely clean of any residue. Once clean, we cut small sections out of RattleTrap sheet, about 3” by 6” using a razor. Since the weather was near freezing, RattleTrap was too stiff to work with so we used a blow dryer to warm up each small section prior to applying it to the van. RattleTrap smells a little of tar and once you place it in one spot, it’s difficult to remove so we had to be careful with placing it. Once it was in the right spot, using the small wooden roller that came with the RattleTrap, run it over the section you just placed to push out any air pockets and ensure it’s stuck. Repeat until done covering the area. 

We could definitely hear a reduction in road noise (even with an empty van) and while we can’t speak for how much less noise there would be if you were to cover more of the van, we are happy with our decision and wouldn’t have spent the extra money to cover more.



We’d done a bit of research on what other people had done with insulation, and there were a few (unscientific) conclusions we came to for ourselves: 1) There is a ton of exposed metal and windows that conduct heat, so there is a limitation to what insulation can do for the van. 2) Most of the floor would be covered by our bed construction, plenty of insulation there. 3) A lot of people miss some part of the van when insulating (the cab ceiling, exposed metal parts, windows, rear doors, screws / metal parts that touch the van body, etc.), but go overboard on insulating only part of the van. 3) As there was no real information on effectiveness, we wanted to keep it simple (and non-toxic). 4) We typically keep a vent open at night for oxygen, so the air flow voids much of the insulation as well.

Sleeping with 2 people in the van, we’ve never really had huge issues with temperatures dropping too much overnight (and we’ve experienced outside temperatures of 10-20 degrees). Whether this is a function of 2 bodies heating up the inside of the van or the insulation we’ve used, we’re not quite sure. What we’ve found is that low temperatures have been less of an issue than staying cool in hot areas. We definitely wouldn’t spend too much time on the insulation in hindsight, for the limitations mentioned above.

We opted for the Denim R13 material on the walls and 1.5” foam insulation on the ceiling. We didn’t want to use fiberglass insulation, given that the Sprinter is a small space and we’d rather breathe in natural materials. Fiberglass is also impossible to remove and you need to let it sit and ventilate several days after installing.

The Denim R13 was a little tricky to find – we were lucky and ended up buying it from a small dealer not far from State College. It may be possible to have it special ordered by Home Depot or Lowe’s, but plan ahead as it may take a few weeks, and we weren’t prepared to wait that long.

Materials Needed:
  • 3 packages of Denim R13
  • Plastic Sheeting – 4mm (1 roll – much more than you need. This stuff’s pretty cheap.)
  • Sheathing tape for fixing plastic sheeting (we used Gorilla tape)
  • 3 sheets of 1.5” foam insulation (for ceiling) – we used 2 layers of 0.75” foam
  • 3x ¼” plywood panels
  • Sheet metal screws – we used existing ones that were holding the OEM plastic wall panels you can check and find here.

We stuffed all the obvious areas of the van with the denim. You can just work with your hands as the denim is easy to tear apart. Some of the larger areas (the large thin sheet metal panels) were covered with denim and then taped so that the denim would stay in place. The 4 mil sheeting is used to create a vapor barrier. It might be better to do this on a dry day rather than a humid one (we did it in cold but dry weather, by chance), but we’re not quite sure on the ramifications. Make sure all the potential openings are sealed so that moisture does not get through the vapor barrier. 

Since the “ribs” in the ceiling are about 1.5” deep, we filled the areas in between with 2x 0.75” foam insulation. Foam is also easy to work with, just cut fitting pieces with a knife, and tape to the ceiling.

Once we finished insulating, we covered the entire driver side wall as well as the passenger wall below the bed frame (the bottom ~40”) with ⅛” plywood. The remainder would then later be covered with cedar panels, which was one of our later, final projects. To do this, we carefully measured out and cut panels to fit. We used the sheet metal screws that previously attached the OEM grey plastic sheets to attach the plywood panels to the frame.


Air circulation and light was a huge factor to us – we both knew we wanted windows in the ‘living area’ and when sleeping or driving through warmer places, you definitely want airflow in the van. So, we knew we needed a vent and, at the time we wanted 4 windows in the back (side windows behind both the driver and passenger, and 2 rear door windows). In hindsight, we would have only wanted to have the windows behind the driver and passenger, not the rear windows, since we tend keep our privacy curtains up 100% of the time in the back. 

Our van is a crew version that came with a sliding door window and the two rear door windows. We ordered the additional driver side window, made by CRLaurence, and had it installed by a local automobile window shop. Installing the window doesn’t seem all that difficult, so we would probably do it ourselves next time. However, getting the window was one of our first modifications of the van, and cutting a 40”x20” hole into the side of the van sounded a bit too scary at the time. While the window is a little pricy, we’re very happy with it. If the sliding door window hadn’t already been there when we bought it, we would have added the same CRLaurence window there. Driver side is the FW621L window, passenger side is FW625R.




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    • Cassio! Thank you so much for reaching out, great to hear from you and we hope we can take you up on the offer! We’re first heading towards Ushuaia and then will decide when we will head to Brazil. Do you have a blog where we could read about your trip? Again, thank you and safe travels. Hope to meet you soon!

  1. Hey! Is that the FW621L window you have on the van by your kitchen? The CR Laurence website says it’s for a 170″ wheelbase, and I have the exact same van as you which is a 144″ wheelbase…sigh.

    • Kris, you’re correct, it’s the FW621L window. The spec should say it’s for both 144 and 170 wheelbase (i think there is no difference in the body up to that point). Hope you manage to find a place that does free shipping!

  2. I am getting ready to insulate our van and we are only finding small rolls of R13 denim 16×48 was that the same packages you bought 3 of about 11$ each? Thanks

    • I believe they were 24×96, we bought them at a contractor supplier. The company website lists all distributors, might be worth checking with some of them.


  3. I just picked up denim insulation of the shelf at lowes in bellingham, wa, they had plenty in stock if that helps your quest.

  4. Hey guys,

    What did you use for the walls? Any surprises? Looks like cedar planking. Which grade/dimensions? Thanks!

  5. Hi, what are your thoughts on Fatmatt? I have a black sprinter and I am currently installing on the ceiling. The rattle trap has a foil side. Do you think it provides some thermal protection? Also I live in Southern California and had 80 degree weather and the roof metal got to about 140. The material will ooze out if you press on it. Maybe this is normal. Oh ya before I forget. Will the smell go away? Thanks.

    • We didn’t put Fatmat on the ceiling of our van. I don’t think it provides much heat insulation. We put 1.5″ of foam insulation for thermal protection, which works pretty well for us. I think the smell in your case may be caused by the heat. Maybe it’s best to keep it to the cooler areas of the van?

  6. With all due respect, we would suggest people use 3M Thinsulate(TM) sound vehicle insulation engineered for vehicles. Unlike cotton (denim) it is hydrophobic and won’t absorb moisture. If denim gets wet, it won’t dry out and could provide a medium for mold to grow.

    • Thanks for the comments, Hein. We used a vapor barrier for our denim insulation to mitigate some of these issues. But you’re right, there is a chance of molding with denim insulation. How does pricing compare for Thinsulate?

  7. We recommend 3M Thinsulate(TM) sound/thermal insulation engineered for vehicles. It is hydrophobic so won’t absorb moisture like Denim. Denim must be also be treated with Borates for fire resistance. 3M Thinsulate is being used by OEMs like Honda and others. It has been thoroughly tested for use in vehicles. Thinsulate is was been used in blankets, coats and glove for years.

    • Hein, I won’t buy thinsulate from you because you go on every single forum or blog and say your thinsulate is the only way to insulate a van. (kinda rude).

  8. Hey there,
    I’m beginning my sprinter conversion this spring and had some questions about the ventilation. I too have a dog, is the one window plus roof fan enough ventilation for ya’ll? I’m debating whether to put a window on the slide door. This blog is a great resource. Thank you!

    • Victoria,

      You can definitely create nice air flow through the van with one side window and a roof fan. We usually open the window and set the fan to blow out / up. It creates a good draft. So as for having a dog, I would say it’s great.

      Now the only time we weren’t happy with ventilation was in extremely hot conditions (in the desert). When it’s 105 degree out, it’s arguably impossible to leave your dog in the car for more than a few minutes, unless you have A/C.

      We had a few nights in Baja where the air was standing still and it was still 90+ degrees at night – pretty unpleasant to sleep in the van even with the sliding door open. A simple solution would be a hand-held fan somewhere in the rear of the van to create some additional breeze. But hey, it’s not always supposed to comfortable, right?


  9. Jakob –

    Your blog has been inspiring me for a long time and I finally make the leap, bought the Sprinter, and am ready to start my conversion process – Thank You!

    I am going to follow your lead on the insulation and sound dampening, but want to add a little more sound protection. Would you recommend doing the insulation (denim) first and then putting the sound dampening over it or the other way around? I went with the Dynamat, but not sure how much I’ll have to “play” with.

    Again, thank you for your sharing your knowledge and your inspiration!


    • Doug,

      Thanks for the nice comment, would be great to see your project. Are you going to document it somewhere online?

      The sound dampening should go directly on sheet metal, it basically gets glued on and dampens any vibration. You could also consider putting it behind the headliner (above the windshield), I think it would add a lot of dampening there. The denim insulation goes on top of the dampening material, and don’t forget to put a vapor barrier to seal the denim from moisture.


      • Thank you!

        I will document it and let you know. I’m not a handyman, so this should be interesting.

        Also, did you use a certain R value for your ceiling foam insulation?

        • There’s about 1.5 inches of space on the ceiling if you want to fill in the space between the structural crossmembers. We just went with rigid foam from Lowes that filled the space, I can’t remember what the R-value was, but we used 2 layers of 0.75 inch foam. The stuff is really easy to work with, just use a box cutter.

  10. It seems like you guys ended up being colder than expected (and installed the air heater) – anything about the insulation job which you’d change in hindsight? Also, it doesn’t sound like you used any insulation on the floor- did this end up being a good idea, or would you insulate this?

    • Hey Eric,

      We didn’t have a heater the entire way down to Ushuaia, and I don’t think it was a big deal. Temperatures rarely dropped below freezing, and even in freezing conditions I think our insulation was just fine. I think no matter what you do the van is not going to be perfectly insulated, there are so many exposed sheet metal parts and windows. For the flooring, the wood seems fine for us, but I suppose you could add a layer of Reflectix underneath it.

      This past winter we were camping in Jackson at -25 Fahrenheit for 2 nights – and we quickly came to the realization that a heater was badly needed for those types of conditions. So in the end it comes down to use case. If your plan is to do a lot of winter camping (e.g. hopping from one ski resort to another), I would highly recommend getting a heater. It made a lot of things easier especially with a dog – we can just leave Leika in the van for a few hours and know that she’ll be fine; it’s also really nice to get back to a warm van after spending a few hours out in the cold. However, if your plan is to spend most of your time on the beach or in the desert, an extra blanket will probably be a better option than an expensive diesel heater for the occasional cold night.


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