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Step 9: The walls: third layer is the vapor barrier

The final step is to add the vapor barrier to seal everything. The goal here is to have no air coming from the van to the fiberglass insulation.
  1. Start by cutting an approximately good size piece of plastic for each section. For sections, we used the large beams already on the walls to dictate where we were going to separate the sections.
  2. For each section, start by using tuck tape on the top part of the piece to secure it in place.
  3. Then make sure to cut out space for the wheel for the bottom piece. Make sure the size is ok all around.
  4. Then tape down the bottom, and finish with the sides.

We had some more delicate cutting outs to do around the ceiling studs, and around the back anchor for the door. With some patience and good scissors, everything can be sealed out properly!

YOU ARE NOW DONE! The insulation for the van is complete. If you want a super extra good job, you can also add some insulation in the panels of the doors. We did not get to this part yet. You can also insulate around the wheels, but this has to be done in conjuncture with whatever you want to build around the wheels.

Once this is done, the next step will be to cover the insulation with a 'pretty' finish so that it is nice and welcoming to live in the van. Some people use thin plywood, some use plywood covered with fabric or rug. We are thinking of using thin cedar tongue-in-groove slats for a very nice finish. This will come in the next instructables tutorial!

As I said in the intro, this is the first van conversion we are working on. We do not claim that this is the best way to insulate the interior of a van, however we believe that we have done a thorough research of online resources and what we present here is a nice summary of the best options we have seen out there, considering our budget, our skills, our schedule, and our future use for the van (winter adventures!). We welcome all comments or questions, since we are curious to see how others have done it.

Questions? Comments?

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<p>Hi everyone. So it seems that there's no consensus on whether or not a plastic vapor barrier is good or bad for the project. I'm afraid I'm not a trial an error guy when it comes to a $45,000 sprinter. I guess the best way to find out the answer is to ask Mercedes Benz how they insulate their passenger models. Once I hopefully find out, I will share it with you folks. Thanks</p>
<p>agree with MattG39 a vapor barrier is a terrible mistake it will keep humidity gently prisonner of fiberglass and will cause rust and moistures. On old vw van camper some aperture are disposed at the top and bottom of all cloisons</p>
<p>Love this, thanks for posting! I have a question you might not know the answer to. But we are trying to gut and insulate our Chevy G20 van. It's not as boxy on the inside as a sprinter... do you think this would be an issue with insulating?</p>
<p>hi! sorry for the slow reply. I think that for insulation the curves won't make a difference, but this might influence what material you can choose to finish the walls. </p><p>Hope the project is going well!</p>
<p>hi! sorry for the slow reply. I think that for insulation the curves won't make a difference, but this might influence what material you can choose to finish the walls. </p><p>Hope the project is going well!</p>
<p>hi! sorry for the slow reply. I think that for insulation the curves won't make a difference, but this might influence what material you can choose to finish the walls. </p><p>Hope the project is going well!</p>
<p>Thank you!</p>
I have question after question dont i? <br>A big debate going on inside my head right now is weather or not to install a vapor barrier i do live in a moist humid climate so a vapor barrier sounds smart but wont that just stop the insulation from breathing or releasing the moister wont the moisture just get trapped in the walls and cause the metal walls of the van to rust <br>Im planning on using wool insulation what do you all think about that
<p>This is a tricky question. I am not an expert at all, but from all the documentation I read about, I think it is better to have the vapor barrier and to make it as air tight as possible to keep the moisture out. </p>
<p>I've been mulling this question for a while too, and have tangential experience with building envelopes from my career (mech engineer). The issue with using a vapor barrier is that you are installing a SECOND vapor barrier. The first vapor barrier is the metal wall on the outside of the van. No vapor is going out that way (minus any odd air passages that certainly do exist - but not in enough quantity for the insulation to breathe well). If you install a vapor barrier you're effectively trapping any small amount of moisture that does make its way in there, and then the insulation will stay wet for long periods of time. </p><p>I've addressed this by not installing a vapor barrier, and by using fiberglass insulation. I'm looking to source some light fabric that I could put where you put the vapor barrier to help avoid any small insulation fragments making their way into the cabin (seems unlikely, but I don't want to risk getting nasty fiberglass bits into the breathing space) but would allow decent moisture transport. Not sure what I'm using yet..... you could use denimn insulation instead, but those products have issues when they get wet. Advantage of fiberglass is it'll never mold up. </p><p>thanks for all the ideas though - been digging using your writeups as launching points for our van!</p><p>Erik</p>
<p>Hi Audrey. Nice work. Just two questions. When you're re-fitting the panels did you have to avoid puncturing the vapour barrier? and Secondly, hpw was did the van turn out? Have you had any issues with rust or condensation?</p><p>I'm fitting out my VW in the UK and your 'How to' is by far the best ive found. Thanks Jake</p>
<p>Dear Jake, thanks for your comment :) We drilled only into the ribs that were already touching flat on the vapor barrier, so even if we pierced it, the screws took the whole hole and the pressure between the wood studs and the metal ribs was so tight that it would not make significant openings in the vapor barrier. Up until today, we have not see problems around rust or condensation, so it seems fine. You can check back on us in the next 5-10 years and see what happens then! I hope we still have the van! Up to now, we are really happy with the changes we made to it. Have fun with your VW!</p>
Super inspiring! I have been looking into this for awhile now and plan to purchase a Sprinter and take it for its maiden voyage this winter. I will post updates. <br>Thanks so much, I know this is a time consuming process to keep up with, but it is much appreciated and will go a long way in helping me out.<br>~~Andrew
<p>Hi Andrew! Thanks for the really kind words :) I really hope you have as much fun with your van conversion process as we did! It truly is an adventure both in the fabrication process and in the trips you get out of it! Enjoy!</p>
<p>Hi, my name is Mike Stubblefield. I'm a retired automotive technical author and I am going to insulate the interior of my 2004 Dodge Maxivan for winter overnighters in the mountains of SoCal where i spend most weekends bagging peaks. As the author of many automotive titles i must say that you guys pretty much nailed it! Nice work, very nice indeed! Thanks very much for posting such a well done and helpful article. You guys rock! I'lll let you know how it goes! Mike S.</p>
<p>Thanks Mike! This is really nice to hear!! Good luck and have fun with your van project!</p>
Do you guys mind links being posted? i hope not, i apologize if you do but i recently insuated my sprinter i used this blog as a guide and then did it completely differently, if anyone is interested in a different approach they can watch this video https://youtu.be/viKhcuIWJuw
Does the bubble wrap actually work to keep the heat out in the summer ? The reflective side faces the metal right so the reflective side faces the wall? Sorry for all the questions i just want to make sure i do this right
<p>Hi! It is hard to know how much every part of the build works. We know that as a whole, things are working pretty well. However, don't forget: this is still a car and it will never be insulated like a house could. If the van is parked in the sun for a full day, it will surely be hot inside when we get in! </p>
Hi i recently bought the same exact vehicle tou uave i really eant to insulatr it but im afraid of condensation and mold have you been having any trouble with mold and conddnsation
Wow i cannot stand auto correct i hope your able to decifer what i typed <br>Do you have mold issues <br>Thank you for replying to my last question im almost ready to take on this task but im one of those must have everything figured out types
<p>Hi! We have not seen any mold for now, so I think things are good. It has been two years since we have installed the insulation and walls.</p>
Does the bubble wrap actually work to keep the heat out in the summer ? The reflective side faces the metal right so the reflective side faces the wall? Sorry for all the questions i just want to make sure i do this right
<p>We would highly recommend folks check out 3M Thinsulate(TM) SM600L noise/thermal insulation that is engineered for vehicles. </p>
I just bought the same van hou have i wanr to insulate it but how nuch does it really help when the back doors amd sliding door have no insulation on them? Doesnt all the heat just escape from the uninsulated doors
<p>Hi MattG39,</p><p>You are right, there is a lot of heat that gets lost through the windows and doors. But you need them in the van to be functional too and to get a view when the weather is nice! ha! So what we have been doing is using curtains and insulating curtains to block off the windows when we are camping. It is not insulated as well as the walls, but will cut the cold for sure. </p><p>Also, we found that most heat gets out through the glass of the windows, not so much from the doors themselves, so with good curtains, it feels pretty cosy inside!</p>
<p>Thanks so much for this - a lot of great advice to mull over as I contemplate the same treatment for an old Step Van. Up to now Reflectix and Celotex was strongest contender, but spray-foam (shaved after curing) is starting to capture my imagination, as it could possibly be it's own vapor barrier.<br><br>I wanted to suggest that adding a bit of thick, self adhesive roofing material to the larger panels would go a long way towards deadening road vibration and quiet the ride. </p><p><a href="http://www.homedepot.com/p/Grace-Ice-Water-Shield-HT-36-in-x-225-sq-ft-Roll-Roofing-Underlayment-5003093/202800770?MERCH=REC-_-PIPHorizontal1_rr-_-203057407-_-202800770-_-N" rel="nofollow">http://www.homedepot.com/p/Grace-Ice-Water-Shield-...</a> <br><br>It would probably be noticeably more resistant to outside noise when camping as well. (That's what I'm banking on, anyway) </p>
<p>Thanks mojoworkin1!</p><p>Yeah, these seem like interesting alternatives too. The only thing I would be careful about with the spray-foam is to make sure you don't put any in to constrained spaces without having a place for it to grow once sprayed. It almost doubles in size and it is pretty strong, so you don't want it to deform or break anything! </p><p>Have fun with the conversion of your van!</p>
<p>My Ford E350 cargo van developed several small holes below the factory rubber floor which developed into surface rust everywhere on the floor. I painted over hard rust with POR-15 and put a breathable outdoor carpet from home depot over the metal.</p><p>Almost every Sprinter I see on the road today has rust weeping down the sides.</p><p>Have you run into any issues with rust on your Sprinter?</p>
<p>Hi AdamG10,</p><p>We have not run into rust problems yet as the van is a 2013 (so it is not that old yet). Also, we live in Vancouver, Canada, so our winters are really not that bad and there is not much salt on the streets in the winter time.</p>
<p>Has anyone experimented with expanding foam?</p>
<p>Hi powderstash,</p><p>We have used a bit of expanding foam for the beams where we could not add other types of insulation. Look at step 8, we describe it there. What we learned is that it does expand quite a bit! (about twice if not more in volume). I have heard stories of people putting some expanding foam in the doors of their van or car and if it expanded too much, it actually deformed the door... so be careful if you go that route!</p>
<p>Hi Guys,<br><br>I am looking at implementing a similar insulation scheme for my camper for an upcoming sabbatical. Unfortunatley for me time is short, so I was wondering if you could give an idea of how long each stage takes. <br><br>Ideally I could calculate using your awesome time lapse, what was the time delay on each photo?<br><br>Any info would be appreciated.</p><p>Regards</p>
<p>Hi TomAtWEG! Great to hear you are starting a similar project! Super exciting! For the timelapse videos, we set it up to take a photo every 30 seconds. Overall, it took us about 12-14 hours to finish the insulation. We always had 2 people at least working, sometimes 3 or 4. Also, not part of the videos is the time to calculate how much material we needed, the time to go and buy it, and the time for setting up the tools and such. But once you get going, it goes pretty fast! </p><p>Good luck on the project and have fun!</p>
<p>Nice job. This really is a complete and proper job with the vapour barrier as that wool can hold moisture. I recommend using tongue and groove like you say - it's easier to fit than cutting bit sheets of ply. This is how I insulated and cladded my van: <a href="http://vandogtraveller.com/fitting-wooden-cladding-van-interior/" rel="nofollow">http://vandogtraveller.com/fitting-wooden-cladding-van-interior/</a></p>
<p>Hi MikeH14, Thanks for the comments! We decided to go with tongue and groove cedar : <a href="http://www.instructables.com/id/Cedar-paneling-for-van-interior/" rel="nofollow">http://www.instructables.com/id/Cedar-paneling-for...</a> and it worked great! We have been traveling with the van on and off for a year now and it is holding up pretty good! </p><p>Your van looks awesome!! Hope the travels are good!! </p>
<p>Was wondering if you still around do you have any shots of the complete van once you finished all the layout?</p><p>Thanks a million for the tutorial looking at vans at the moment for travelling around Europe on vacations for the years ahead. </p>
<p>Hi Killerspec,</p><p>Sorry for a slow response! We are still working on the van. We decided this was going to be a slow process, so we could still go travel with the van as we are building it. As of now, we are done with the walls, we made a platform for storage in the back and we build a table with benches and a bed. You can find all those tutorials here:</p><p><a href="http://www.instructables.com/id/Storage-platform-for-the-back-of-your-Sprinter-van/" rel="nofollow">http://www.instructables.com/id/Storage-platform-f...</a> </p><p><a href="http://www.instructables.com/id/Cedar-paneling-for-van-interior/" rel="nofollow">http://www.instructables.com/id/Cedar-paneling-for...</a></p><p><a href="http://www.instructables.com/id/Bed-Table-and-Benches-for-camper-van-All-in-one/" rel="nofollow">http://www.instructables.com/id/Bed-Table-and-Benc...</a></p><p>I have another one drafted for the cushions of for the bed, so stay tuned! Next step is to build the kitchen unit :)</p>
<p>Thanks for getting back to me good luck with the rest of the project and I look forward to seeing the fruits of your labour in the near future.</p>
<p>Did you make sure there are no access covers for the fuel pump or rear axle mounts that go throught the bottom of the van?</p><p>If access to the fuel pump is through a cover in the bottom, you'll have to have the flooring sawed to fix the fuel pump, clean the strainer, etc.</p>
Hi, <br>Fiberglass (and most any foam) insulation is bad news. Take it out now and avoid the rust problem that follows. Seen way too many VW buses over the years with the nasty results. Sealing it with plastic will make it load up with moisture even worse/sooner. Only way to make that work would be to cut the sides of the van and install vents to allow out the condensation like as done to houses.
<p>Veewee111...Hi...I was thinking the same thing about the condensation. Starting a van build now and wondered if you had any solutions to the moisture issue...</p><p>Thanks!</p>
Sent the below to a fellow who Pmailed us about this problem. Have added some more to it to post it here.<br><br>There are two catagories to insulating a camper or any other structure, short term or long term.<br><br> Short term like a few days to a few weeks then you could insulate the walls when camping in temperate weather, but need to allow moisture to get back out of the walls back to the interior to be let out of any venting window. We have side windows and a roof vent that can be slightly opened on sunny days, that really helps.<br><br>Long term for months and especially in artic conditions one would need to insulate with vapor barrier and cut vents in the outer walls to let moisture vent out all of the time. VW did this to the pre-1968 non-walk thru panel buses with a panel sealing off the cargo area from the front bench seat, by punching vents in the upper rear corners of the rear cargo area to prevent moisture build up.<br><br>Image looking forward to the panel behind the bench seat of non-walk thru panel bus.<br>http://images.thesamba.com/vw/gallery/pix/267582.jpg<br><br>Here is an interior shot of a special order walk thru panel with the upper cargo area vents in the body. These vents were usually only in the non-walk thru panels.<br>http://images.thesamba.com/vw/gallery/pix/1116625.jpg<br><br>Here is a post on a VW website we have weighed in on about the subject for short the term.<br><br>http://www.thesamba.com/vw/forum/viewtopic.php?t=153837&amp;postdays=0&amp;postorder=asc&amp;highlight=insulation&amp;start=0<br><br>Thinking of using thin 1/4&quot; (6 mm) styrofoam glued to the mylar coated bubble wrap. Neither of these insulation materials will sponge up moisture. Insulation needs to be thin enough to not be packed tightly in there against outer sheet metal when paneling is in place. Want a bit of air space so air flow can pass thru and get out the moisture from behind the 1/8&quot; (3 mm) plywood. Having the mylar coated bubble wrap with the bubble side against the outer sheet metal will allow air to dry out any moisture that gets in between the insulation and sheet metal. The wood unlike plastic will breath back out the moisture when heated up in the sunshine or a heated garage. Will use velcro in places to hang the insulation from drooping down and at same time allow air flow around edges of the insulation. That way insulating panels stay in place, but easy to remove for body repairs or inspection.<br><br>Was in the USAF and got to handle the insulating panels used in cargo aircraft like the C-130s. Blanket type material with velcro at edges. Very cold at 30,000 feet over the North Atlantic with temps down near -50 F. Would pull back a panel, and slip in a 1 liter bottle of Moutian Dew for fifteen minutes. Pull the bottle back out and shake up for slurpies. Yum!<br><br>Hope this info helps!<br>
<p>Wow Veewee111!! This is quite the response! Thank you so much for sharing all this information. I think this should help other folks figure out what they need for the usage of their van. I think a key point that you shared is the need to have air circulation between and around the insulation. In our build, since our cedar panels are almost floating in front of the metal wall, we were able to have about half an inch of air circulation. This should definitely help. </p>
<p>Ah that's sweet as! Nice job!! Did you find out about the temperature difference? And have you had any problems with the setup as of yet I.e rust, dust, ventilation, condensation or anything else? I am looking to carry out the same to my Mazda bongo to live in the winter months whilst at work! So very curious on how it's going? :D enjoy!!!</p>
<p>Hi smidGe777! Thanks for the comments and sweet that you are starting a similar project! We have had the van since November 2013 now, and finished installing the insulation and wood paneling walls (instructables to come...) in December 2013. We have used it to camp in the winter, spring and summer. Up to now, we have not had any problems with it :) We are pretty happy with how things are working for us and it seems like there is no condensation happening in the walls (although it is hard to see because most of it is now covered in cedar panels). We did not do a serious comparison for the temperature difference, however, we spent nights at -10 or -15 celsius and we were fine. We use a small propane heater (made specifically for indoors environments, and with the ceiling vent open) and it has kept us warm enough. For ventilation, the ceiling vent is crucial, and even in winter time it is important to leave it a bit open at night, to let the humidity get out. We have also definitely noticed that the windows and the side door were conducting the cold from outside, since they were not insulated. For the front and back windows, we made curtains. For the side door, we are in the process of adding a window, and eventually curtains as well. We used a light wool for the curtains. </p><p>Enjoy the project!</p>
Nice one! Glad your happy with your project! And thank you for your wishes and advice :D

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Bio: I am an industrial designer, an interaction design researcher, a painter, a jeweller, a skier, a camping enthusiast, and I just love to make stuff!
More by AudreyDesjardins:How to sew cushions for a camper van Bed, Table, and Benches for camper van - All in one! Cedar paneling for van interior 
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