Insulation is by far the most commonly misunderstood aspect of a camper van, skoolie, and recreational vehicle DIY conversion. And for good reason– there is so much misinformation out there! We spent weeks researching radiant barriers, vapor barriers, and dozens of insulation options for our sustainable non-toxic conversion van. We’re sharing the lessons we’ve learned to help you have the best conversion van with natural non-fiberglass insulation. Don’t make the same mistakes we’ve seen hundreds of vanlifers make! Put down that Reflectix and read this post!
Disclaimer: Between the two of us, we have 15 years experience in construction and green building, but we are not engineers or physicists. Although we have strong opinions that are backed by research, we are not saying that our word is the end all be all. We are 100% open to ideas and would love to hear your comments and suggestions, especially if you are an engineer or physicist or work in the insulation industry!
Lesson One: Don’t waste your time on a radiant barrier! They do (almost) nothing!
Radiant barriers are VERY popular in the van build world, so we’ll likely get some backlash on this. Regardless, we’ve done the research and we’re ready to make a bold claim: Everyone you see installing Reflectix on their van walls is doing it wrong!
When we first started googling “how to insulate a campervan” we saw Reflectix everywhere. Instagram, same thing. Even Sportsmobile (a popular camper van company in the US that mainly converts high-end Mercedes Benz 4×4 Sprinters) has an “arctic package” that includes Reflectix on the whole interior. In theory, this concept works– just like the reflective visors you put under you windshield, reflective material inside a van can reflect away some of the sun’s heat (or keep heat in the van during the winter). The problem is that everyone we’ve seen is installing Reflectix incorrectly, which renders the product useless.
For a quick science lesson about radiant versus conductive heat, this video (produced by a radiant barrier company) sums it up pretty well:
If you skipped the video, here’s the takeaway: Reflectix does a great job of blocking radiant heat if it’s installed properly. For installation to be correct, there MUST be an air gap of at least 3/4″ between the foil and any other material. If there is no air gap, the foil acts as a heat transfer conductor and will actually work against you!
An “air gap” must literally be a void space for air only – no paneling, no batt insulation, nothing can touch the Reflectix or it will not block radiant heat. So when you see people sticking insulation directly on top of Reflectix, they are wasting time, money, materials, and actually making it easier for conductive heat to pass through into their van.
To properly install a radiant barrier in your van just isn’t feasible– you would need to run ¾” furr strips around the entire interior of your van and then ensure no insulation or paneling touches the foil. This would take up a LOT of valuable space in your van.
Is it worth it? We don’t think so. Radiant barriers aren’t used much anymore in the residential construction industry because they don’t do very much. Independent studies suggest radiant barriers only reduce cooling energy bills by approximately 2 to 10 percent. It’s estimated that the R-value of a radiant barrier is at best R-value 4.2. This small savings isn’t worth it for the amount of space you’d lose in a proper installation.
We’re grateful for other vanlifers out there who are helping to spread the truth about radiant barriers. Don’t waste your time or money!
Lesson Two: Don’t install a vapor barrier in your van!
Many vanlifers install vapor barriers in hopes of preventing condensation moisture from getting to the sheet metal of the van. Unfortunately, installing a vapor barrier in your van will actually increase the likelihood of mold and rust. Air exchange between the interior and exterior metal walls is essential to keep moisture and condensation in check. When you add a vapor barrier, you are trapping the moisture you create from breathing inside the van. This moisture has to go somewhere and so it eventually runs down to the floor of your van, where it can eventually cause rust and even mold. Mold is no joke and can have serious negative health consequences, so we recommend foregoing a vapor barrier and using insulation that will allow your van to “breathe.”
Though spray foam insulation kits do a good job of sealing your diy campervan, you really want your van to breathe, and so this can be overkill and trap moisture in a tiny space.
Lesson Three: Choose non-toxic, moisture-resistant insulation!
There’s not a lot of indoor air in your van, so it’s important for your air quality to be as healthy as possible. Sorry to be a buzzkill, but most conventional building insulation materials have toxic or potentially-toxic chemicals. Choosing non-toxic camper van insulation was important to us, so we were able to rule out the following types of insulation right away: fiberglass (toxic when inhaled/installed), cellulose (formaldehyde binders & flame retardants), rock wool (formaldehyde binders), foam board (toxic styrene), 3M Thinsulate (contains potentially toxic polypropylene), and spray foam (contains potentially toxic polyurethane and is also both difficult to install & non-removable). For a complete guide to non-toxic sustainable van products, check out this post!
NOTE: We started going down the rabbit hole researching all the potentially toxic chemicals in insulation and other commonly used construction materials. Ultimately, we decided to exclude this information from this post, but if y’all are interested in the dirty details about various construction products (and the reason we’re building sustainably), please comment below and we’ll write a post about it.
We narrowed our search down to three non-toxic insulation options: recycled denim, hemp, and wool. Denim is not moisture resistant (when it gets wet, it stays wet), which can cause mold. Hemp seemed like a good option, but it typically comes in concrete blocks which would be difficult to install in all the tiny cracks and crevices in the van, so we decided on….SHEEP WOOL!
Sheep wool is the BEST non-toxic insulation for your camper van conversion– it’s sustainable, naturally fire-resistant, breathable, doesn’t retain moisture, easy to install, and it’s literally sheep wool, so there are no toxic chemicals. Check out Black Mountain manufacturer information for information about the wool we used.
HOW TO INSTALL WOOL INSULATION IN YOUR CAMPER VAN
Black Mountain R-13 sheep wool 16″ rolls (we used just under 9 rolls for our 146″ wheelbase Nissan NV2500 high roof van)
Low-VOC spray adhesive (we used 3M Super 77, which isn’t the “greenest” choice, but at least it’s low-VOC)
2-4 gallons Noxudol Sound Damping compound (the amount will vary depending on your van size and how much surface you choose to cover)
Paint brush (preferably an older brush)
0) Step 0 is to deep clean your van. Deep, deep clean the van. Take out the floor mats and clean them, get deep into the crevices and clean everything. This is your new home and this is your only opportunity to do a truly deep cleaning of the entire van before you start your conversion. Be sure to identify any potential mold areas and spray with a mixture of bleach and water. Allow the van to air out completely for a couple days after spraying bleach before you start your conversion.
1) Identify and tape off the areas you plan to use sound damping. We recommend using this on top of any exposed metal that’s not going to have wood, paneling, or flooring surface on it, including entryways, wheel wells, and step areas by the doors. Depending on your flooring selection, you may want to cover your entire van floor with a layer of the Noxudol, but we didn’t because we added cork as part of our flooring installation. Using an old paint brush, spread a thick layer of the Noxudol on the applicable areas. Repeat for 2-3 coats and be sure to let the product dry between costs.
2) Start pulling apart one of the rolls of wool and use the small pieces to fill all the cracks and crevices in your van. Be thorough to ensure you’re insulating deep in every gap in the walls, floors, and even in the small holes in the ceiling and wall beams. These areas can be tricky to access (we took advantage of having our 11-year-old nephew with little hands helping us out!), but do your best to be thorough. There were some places in the panels surrounding the doors/windows where the holes were too small to access, so we actually drilled holes in the sheet metal to reach them. You want to fill as many of the small cavities as possible with wool. Don’t force too much wool in these areas, just moderately fill the spaces completely.
3) Screw in 1/2″ furr strips on top of all the wall and ceiling beams. This will give you something to attach the wall paneling to and provide more space to fill with insulation.
4) Spray the wall and ceiling crevices with adhesive and stick the roll of wool to the walls and ceiling, spraying each small area at a time as you go. Use as little spray adhesive as possible and wear a mask– it’s very sticky and doesn’t take much– it’s just meant to hold the material in place until you get the wall panels up. (For a completely non-toxic option, you could also take painters tape and criss-cross it over the wool to keep it in place.) The wool comes in 3″ thick rolls, so that will be the thickness of the insulation around the interior of the van. You don’t want to squish the wool too much because it’s supposed to be installed at the thickness it comes.
NOTE: Be sure to previously identify and mark where you will have your vent fan, AC, windows, or anything else that will be cut into the metal of your van. You’ll want to block off these areas so you don’t insulate over an area that’s going to be cut.
5) In order to save as much head room as possible, we decided to only insulate the floor a small amount. We didn’t raise the floor up at all, we just utilized the very small 1/4″ gap in the existing floor ridges that otherwise would have been dead air space. We rolled small pieces of the wool between the floor ridges and installed our 3/4” plywood subfloor directly on top of the beams and small rows of wool. We added extra insulation when we installed our camper van flooring, by adding a layer of cork underlayment below our linoleum flooring.
6) Once the van is covered in insulation, you’re ready to put up the wall paneling. We recommend doing this step soon after completing insulation, so the insulation doesn’t become loose and fall down.
I’m not going to lie, it smelled a little like a petting zoo at first, but after a week or so, all the essence of barn animals was gone! We’re loving the wool insulation so far– the van stays cool when it’s hot and warm when it’s cold!
What type of insulation are you using for your camper van conversion? We’d love to hear your comments and suggestions!