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L4H3 no skills van conversion - build log

11233 Views 89 Replies 17 Participants Last post by  McNulty
Hi all,

I was given a warm welcome at the introduction section, and thought I might make a build log for my Fiat Ducato L4H3 conversion. I know now, that, these are not identical to the American "Promaster" as I first thought, but merely based on the same chassis. My cars knowledge is very limited ;)

I said "no skills" because I basically have none. I am a software engineer, and if you know anyone in software development, you'll know they have zero practical skills :D So I have started this project to learn a lot, and hopefully complete my dream van too. So crossing fingers :)

As for the van, it's an extra tall H3 model, as I am 6'4, and thats the only version I'll be able to stand up in. So tall one it is.

The plan is to make a van that I can use during winter and also live in for for extended periods of time. I don't have any floor plan, or anything else for that matter, planned out. What I do know, is that I will have a fixed bed with a big garage. I need to place all my sports gear, and its quite a lot, so need lots of storage in the back. I guess it also makes construction a little easier. I'll also design it around 1-2 people, not more. It will mostly be used by myself alone, so not going to design a common area with room for 4 people.

I'm also working full-time, so don't expect updates that often. I have to make use of what spare time and weekends that I have. But It will be nice to share some updates once in a while, and maybe someone will have some pointers when I'm stuck along the way :)

So first two days, what I've managed so far:
  • Got the side walls down, and cleaned the interior.
  • Fixed some butyl for sound deadening some of the walls (although not completely finished yet).
  • Got a massive headache from all the cleaning detergents (note to self, more ventilation next time).
  • My back feels 80yrs old.

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Discussion Starter · #4 · (Edited)
It's nice to see what an extra-tall (H3) looks like on the inside. Lots more storage space in the forehead! @Lolaeliz beat me to it. Ditching the cab partition and adding swivel seat-bases would also bring the cab seats into play in the living space and eliminate the need for additional seating, freeing up valuable space for other stuff.

Here is a handy floorplan helper. Your L4 has the same floor footprint as the Promaster Long Body diagram. However, the L4 over here is properly called a Promaster 3500 EXT, but it only comes in H2 here.
Thanks for the floorplan helpers!

As @Lolaeliz also pointed out, there are some tradeoffs by keeping the cargo wall. However, I do like the design options I have by using the wall. I don't mind the hassle of going out from the drivers cabin and in the sliding door, makes the van more "stealth" which is also one benefit.

Either way, If I want to be able to actually use the car before its registered as an RV, there are tax regulations that prohibit me from modifying that wall. So there is that. So I make everything just a lot easier by designing everything with a wall still in place, so that will probably be the way forward for me.

Oh, and I simply love the extra cargo space in the forehead section :)

And yes, next step, floor plan :) (besides some rust treatment which I will do the coming days)

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Discussion Starter · #6 ·
Ahh! We have variations on tax and registration limitations over here too, but yours sound a bit worse.

"Rust treatment"? Promaster bodies are galvinized at the Mexico factory. They rarely rust (like Sprinters). Are Fiat Ducatos different?
Yes, they are quite strict. As long as the van is registered as a "utility vehicle / cargo van" the wall cannot be changed. Modification of any kind will trigger a tax-class change to regular vehicle (according to some annoying EU directive), which is a lot (probably in the area of 20k). Well, only if you get caught that is, but I'm not taking any chances ;)

Maybe "Anti-rust-treatment" is a better word for it ;) There are just some areas with bare metal where the paint has come off, so I thought I'd be a good idea to treat those. A few spots of surface rust in the cargo area, but other than that, its spotless (Its an 2018 model, so a few years used). The galvanised body was a big selling point for these vans, something I did not know before after I bought it :D

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Discussion Starter · #10 ·
First weekend with some actual work.. two steps forward and one back :p I feel that I'm making no progress what so ever, but I guess what I have learned is that things take a lot more time than I think :D

I'm posting some pictures of my progress for anyone interested. What I've done this weekend:

  • I planned a little bit ahead (as this was a lot more fun than the boring painting part) and designed and 3D-printed a cover for the duct, so that I can seal of that lower "rocker panel channel" when I get to the insulation part. Not sure if its a good idea, guess I'll find out when I get to insulation sometime. If it works I'll print it in a more durable material like PETG or CPE.
  • As I'm a little annoyed by the road noise in the drivers cab, I tried to insulate the cab, starting with the doors. I quickly managed to destroy the vapor barrier. Of to a good start. I then thought, oh well, at least I can insulate the door, and cleaned it and put on some alubutyl sheets. I then discovered that the "foam mats" (to put on top of the butyl sheets) I ordered was in fact not foam mats, but more alubutyl sheets (just the more expansive brand to make it more annoying). So that was a complete waste of money. I now have one door without vapor barrier or noise mats :D Anyone else have noise treated the driver cab? I wonder if it's easy to access and helpful covering the wheel arcs, if its even possible. I struggled with all the panels, so had to call it a day this time around.
  • I finished the interior paint job. I might have gone a little overkill on the sanding and painting. I probably could have used the white paint the for bumper too (since it will be cover up anyway), but my ocd wouldn't have it.
  • Almost finished with the interior noise deadening. I think I might have fixed too much of that stuff , as I'll keep the wall, the noise deadening might not be worth much on the side walls. For the roof I've tried cutting strips of the alu sheets to fit within the grooves. The idea was that this will in addition to help with noise, fill those "gaps" for the insulation later, time will show if it's a good idea.

So that sums up my weekend. Making some progress.. very slowly. Next weekend I'll try to fix what I destroyed today :)

@SteveSS I added a better photo for you of the headspace section :)

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Discussion Starter · #12 ·
Love all that extra-tall space! I'd have a hard time deciding between upper cabinets and windows up there.

Your noise problems will largely go away once you insulate. The butyl sheet makes a noticeable difference at this point, but insulation will improve on that a great deal.

There is very little room for Insulation inside doors, plus it can get wet in there. I have not looked myself, but there may be some room for insulation on the back of the interior panels, like there is on Transits. Maybe wait and see what you think after insulating the rest of the van. The vapour barrier looks to be the same foam sheeting used for packing material. If you can't find a source for that, plastic vapour barrier sheeting for homes should work, too. That's what I found inside my old Ford van's doors. Get some double-stick outdoor carpet tape, and you'll be back in business.
Yes, I've decided for extra cabinet space, but Windows sure is a tempting idea.

For the doors I can also see there are drain holes in the bottom. The "foam panels" I thought I ordered are thin, and will fit behind the window-slides (?) so I'm good there (Dynaliner I believe the product was called). Anyway, I've started now, so got to finish the job, lol. But a good point for the rest, I'll wait until after the insulation to see the result then. It might be good enough. At the very least, I want the doors to make a "floof" sound and not the "clank" sound ;)

I'll source some regular plastic sheets and maybe some butyltape and fix it again. Probably after 15 hours of scraping work to get the sticky glue-stuff removed.

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Discussion Starter · #14 ·
any idea what happen to crack/rust at rear of cargo space???? a blanket on wire/shower rod between cab and cargo area will greatly reduce noise

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Don't know for sure, but it looks like the rubber seal on one of the back doors are gone, so I'm guessing it's been slamming the metal every time it shuts. Need to get a new rubber seal. I sanded it down and painted, hopefully that will do the trick.

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Discussion Starter · #15 · (Edited)
I also came at tyhis with no skills––except designer skills.

Do you have a floor plan to post? If not, pull out some graph paper and give each square a value. Then start laying out where you want the bed, the kitchen, the wetbath, (if you want one). When you're dealing with such a small space, you really need to consider every inch and the only way to do that effectively is in pre-planning. Your counters, sink, faucet... all might need to be smaller than you would buy for a house. A floor plan is your best buying guide.
Since its been raining constantly for the past few weeks (and I'm mostly working from outside), I've not managed to do much actual work lately, but I have however finished my floor-plan, I think! It's at the very least ambitious, so we'll see how I get on, but I'm quite happy with it. I've attached a few drawings of my plans to this post.

A few notes on the plan:
  • According to regulations, I need a cabinet (minimum size 40x40x75cm), so I've added an almost full size one. Since I will do a lot of kitesurfing, I've planned to channel the diesel heater into the cabinet, effectively making it a fast drying cabinet.
  • As the car is registered for 3 people, I need at least the same amount of sleeping arrangements (regulations), 3 beds (but they don't have to be "fixed"). Since I'm 6'4 I can't have a full sized fixed bed, as that would occupy too much space, so I've based the bed on a pull-out section.
  • It's based around keeping the cargo wall.

I've also fixed and sealed up the rocker panels, as I've mentioned in another post, they were leaking quite a bit, especially around the marker lights. I don't want to worry about potential leaks behind the insulation, so I've done the following:
  • Removed all rocker panels (and breaking 40-50 plastic clips in the process - put my anger management to a serious test).
  • Cleaned and prepared the surface.
  • Designed a 3d-printed bracket/spacer to seal the open gap between van skin and rocker panel that was leaking.
  • Sealed every plastic clip with a butyl sealant.
  • Sealed the top- and sides of the rocker panels with sikaflex. In retrospect, I should have made a better masking job. Oh well, next time.

Next I plan to do the maxxfan install before I start with building and insulating the floor. Oh, and I've also found that the electric caulk-gun to be the best tool ever :)

Your noise problems will largely go away once you insulate. The butyl sheet makes a noticeable difference at this point, but insulation will improve on that a great deal.
I should have listened to you! I finished insulating both doors with alubutyl sheets and Dynaliner (yes, the expensive stuff). The leftovers I used to replace the original insulation under the hood. I thought it was a good idea at the time :p I did sound measurements both before and after treatment, and the result? ZERO difference. I could not hear any difference, and the measurement actually gave me 1dB higher sound pressure lever after treatment, lol. So that was a complete disaster. Well, I can only hope for a slightly better sounding stereo at least. I guess I've learned something at least.

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Discussion Starter · #16 ·
Happy with my progress today.I made a hole in my car, which I’ve never done before :) it was a lot easier than I thought it be. So I mounted and installed the Maxxair fan, at what seemed to be a template cutout in the roof. So to make the installation easier and level, I used this area for mounting. I did not measure properly regarding my planned wall, so I'm just hoping it will fit within the design, crossing fingers :p

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Discussion Starter · #17 ·
I cannot believe how much more time it takes than I anticipate, every single time :D I was suppose to complete the entire floor, fix it, and attach the floor base, but no, all I've managed in 3 days is to cut everything to shape. I guess going at it alone takes more time :)

I think I am the only one I have seen out there that has put 50mm (2") insulation in the floor. If my math is correct, I have just about enough headspace left for the extra insulation in the floor. I've gone down that route because I will use it in the winter, and hate cold floors, so I'm hoping some extra insulation will help, we'll see.

I've cut the batons and XPS insulation to shape, and my back is hurting like a motherf...! Need to work on my posture :) I've also placed the batons where I think the furniture and other inventory will be placed for extra support and easy fixing to the floor.

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Discussion Starter · #20 ·
2” Thick XPS 👍. Not seen much here & for you only really increases your step up height from the ground.

If I understand that “Jackodur 300 XPS” has a 44 psi (300kPa). What was your thoughts on the battens? Also are they pressure treated (the colour makes me believe they are, but I’m from Canada so products could be different). If they are it would be best to research what fasteners to use, as PT chemistry can quickly corrode the wrong fasteners.

It looks to me that you have done really nice work so far for a novice. I do not know if I would have installed battens, but maybe I am missing something.

View attachment 79700

Things taking a long time to build is pretty typical in a van & especially for 1st timers. Ya just adjust the time expectations.

Good Luck with your build !!
Hey, thanks!
I've used "Jackofoam 300" from Jackon (maybe its a different name over here..), but it looks to be the same product. I've read that XPS performs a lot better than other products like polyiso in cold temperatures, so thats why I chose XPS. I'll consider Polyiso for walls / ceiling though, and I'm planning on using Armaflex in the hard to reach spaces (and oddly shaped parts like the wheel wells).

Yes, the battens are pressure treated. I thought that would be better for mold protection, but then again, I don't know these this very well, so my very simple logic thought PT must be the way to go, since the price was almost the same anyway. I did not think of any reaction with fasteners to be honest..hmm. I'm anyway planning to fasten them with Sikaflex, not making any holes in the floor (I'm keeping the bulkhead, so I have that extra protection anyway in case of an accident).

As for the battens, the idea was to have a solid base to mount the interior into. I've also seen every other youtuber do this, so I guess I did not think of leaving them out.

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Discussion Starter · #24 ·
I use XPS high load on the floor of my vans without battens. I use EXP high load not for the psi rating but for the water impermeability. Polyiso can absorb liquid water and when it does & when under “load” it can turn to mush.

The only drawback using XPS under your floor is the ability for that insulation to telegraph noise “squeaks”. It is simply less “squeak resistant” than polyiso.
Yep, I've already noticed the squeaks. I've made sure to cut away material along the sides against the van skin, and will be using expanding foam to fill the gaps. Hopefully that will make it squeak free. That would indeed annoy me a lot.

Roof & Walls; I use polyiso as IMO there is less likely chance of polyiso absorbing liquid water. In my 2021 build I will use foil face & aluminum foil tape the raw edges. Walls & Floors in direct sun & in hot climates can really heat up (also depends on your van colour & roof mounted solar panels). Polyiso performs much better than XPS for high temp heat. Polyiso performance drops off at the opposite spectrum “extreme cold”. For the climate my van will “live” it makes sense to use polyiso in walls & roof. YMMV.
Aha, I was under the impression that polyiso also was water impermeable, but its only the aluminium coating that keeps it from being a sponge? Like, for some of the uneven surfaces I initially planned to "cut into" the polyiso block to make it fit (some "bumps" in the van skin, like the lower panels), but then thats a bad idea I guess (unless I tape it). Another use would be to "drill holes" to make it fit over the plastic clips holding the rocker panels in place. The aluminium surface also acts as a reflective surface (with an airgap) i suppose, unlike XPS as an alternative for the walls & ceiling too, so there is that upside too.

Regarding “seeing others on Youtube”; I understand the human nature. You have stumbled upon & become a Forum Member. I have a bias towards “The Forum”. IMO for Promaster(ish) van builds this Forum” is “The Place To Be”. I post a lot of “crap” on here & some of it might even be right. This is the only van forum I am on (actually it is really the only forum I visit). I think it is a good idea to look at Youtube for ideas, but I think it is very prudent to vet those ideas here. There are many experienced science based DIYer Members here & a mountain of knowledge, albeit sometimes contradictory but that is the great thing about this forum it is a wonderful venue to share opinions & back them up with Science & Logic (rather than emotion).
As I am starting out without any prior skills or experience, we all have to find inspiration somewhere I guess :) I've used countless hours on youtube and van conversion blogs and articles, some good, and others not so much. As always, I try to keep an open mind, and figure out what information is reliable and what would work for me or not. I've looked at this forum a lot too, and I have to say, its a very active and welcoming forum. It will soon be on my top list I guess :)

Lol, before I started this project, the only car related stuff I had ever done was changing a windshield wiper. Set the bar high and dream big right? :) I am however an engineer (although a software developer) so I'm at the very least used to technical stuff and not afraid of using Google to figure stuff out :)

You can use your build thread here to your advantage (if you wish), but posting questions on your intended design prior to building & obtaining opinions/ideas to assist you in your design. You are Design/Building a DIY van 1st time? It ain’t the building that is hard (exception back aches), but the Design.

The Forum Membership has a wide spectrum of; Architects, Engineers, Scientists, Construction Types, Mechanics, & Much More - Most willing to help you out. All ya gotta do is ask 😁👍
Thank you so much. I will probably do a little bit of both as the project progress. I don't have anyone else to throw ideas and questions at, so I love a helping community :)

Some “light” reading for you if you have an interest in insulation (one of the worse misunderstood DIY van build topics there is on the internet in my opinion);

@GaryBIS insulation tests;

My reference to polyiso absorption (do not get fooled by the foil-face that is rarely sealed & easily punctured real world) look & the raw polyiso.
Yes, the more I read about insulation, the more confused I get :D Its a never ending topic it seems :) I've gone through youtube and countless van conversion blogs and articles. I don't like to make uninformed or wrong hasty decisions, so I take my time doing research, but even then, its possible to get it wrong I guess :)

When it comes to insulation, which are all my next steps, my current plan is as follows:
  • Floor - XPS 50mm. I plan to adhere it with expanding foam.
    • Also expanding foam in all the cracks and smaller areas not covered by the XPS panels.
    • Aluminium foil tape over the battens to complete the "vapor barrier" as the battens are the only thing not water impermeable (although, if the battens get wet I probably have some more serious issues at hand).
  • Walls - Polyiso 50mm. I plan to adhere it with a non expandable fixing foam, like Sika FoamFix.
    • Expanding foam around the edges.
  • Ceiling - Polyiso 50mm. Same procedure as for the walls (and leaving a small airgap for the panels).
  • Inside the "ribs" (or whatever they are called?) I'll use either expanding foam or some sort of mineral wool (or a mix between the two depending on the space).
    • Some parts needs to be accessible after installation, like access to the brake lights, etc.
  • Cover all bare metal and ribs with a "reflectix" type of material to close any thermal bridges and prevent moist air from condensing on the cold van skin.
  • For the headspace above the drivers cab, inside the doors and wheel arches I'll use Armaflex. Its very flexible, has the same thermal properties as polyiso and also water impermeable. Only downside is it's only 25mm (1") thick, and slightly more expensive.
    • Maybe I'll add some mineral wool too some hard to reach places. After all, the doors have drain holes, so I'm less worried about moisture buildup inside the doors than other places.
In general, I'd like to use as much water impermeable material as possible, and not base everything on a vapor barrier, thats one way or the other, is going to fail at a point. Water will find its way no matter what I guess :)

I've also looked at thinsulate, which people seem really happy about, but its near impossible for me to source it, as no one sells it in my parts of the world. International orders get really expensive fast, so I've put away the idea of using Thinsulate.

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Discussion Starter · #27 ·
I think most of your insulation plan is good. Here is what I believe;

First; The only real way to deal with the multiple "Vapour Barrier" issue is to do a "Total Spray Foam Job" It is my opinion that this "kinda" makes the van metal skin and the spray foam one "almost" monolithic thick vapour barrier. This "kinda" solves "the vapour barrier issue". I almost did this in Van #1 but opted for what I think is the next best thing if not a "Total Spray Job" which is XPS on floor & Polyiso on walls and ceiling and Great Stuff Door & Window spray to fill in other areas. There are other reasons why I did not choose a "Total Spray Foam".

For me, I would not use in a van; Denim, wool, fiberglass, mineral wool (I did experiment with this but took it out and used polyiso), Thinsulate, Lizard Skin (but I have had Oxtail Soup)🤫.

Plywood is typically a vapour barrier (especially if sealed or exterior grade).

If the design can incorporate a small amount of insulation on the warm side for any thermal breaks - great, If not a "sill gasket" on the warm side even helps (maybe more than stringing thinsulate into the cold side of the ribs etc). The Ribs in the PM are about 1" off the van metal roof, so if you have more had room to start and can give up another 1/2" in head clearance 1" between the roof ribs and 1/2" over the roof ribs would at least get you some R Value on the warm side of the thermal bridging roof ribs. This is what I consider a high cost vs little gain item, but I thought I would mention it.

Be aware of the major thermal loss areas of your build & have a plan on how you are going to deal with that. Uninsulated Cab with huge areas of glass, Thermal bridges such as rear doors and slider door, Windows are all massive thermal loss areas. @GaryBIS has a pretty good thermal loss calculator on his build site. You would have to configure it to your Van, but it will get you there to understand what your thermal losses might be & what size furnace you might need.

At the end of the day my perspective on "Van Envelope" is it will not be perfect, & I will just do a reasonable job and attempt to reduce/eliminate mould food, be conscience of the moisture I introduce into the van with my use "cooking etc", as my main goal is to be comfortable and to not grow mould. So I will do what I feel is a practical best practice within reason.
Thank you for the detailed and insightful reply. May I ask why it is that you don't recommend any of the mineral wool of fabric types of material? Is it due to the fact that it will be "sandwiched" in between two vapor barriers, effectively?
For example, unlike to roof ribs (which are quite small), the side ribs in the walls are quite big, and would leave a huge heat bridge if untreated. I will run conduit and cables through, but some are big enough to consider other types of "filler" material than spray foam I guess. Or at least, I am considering it.

So, I'm still in the process of figuring out the best way to insulate ribs and doors properly. Another idea I've had is to use mineral wool in the doors and not a vapor barrier in front, just cladding, so that the material can "breathe".

For the roof ribs, I need extra space for the insulation (50mm) so my idea was to attach battens on top for easy installation of the roof.

Obviously, for the really big thermal routes like windows, I will have to construct a cover I can place on top to stop all the heat from escaping. I have one big side window, and two at the back doors, so they have to be covered during the night unless I want to freeze to death :)

As for the foam, I am also not able to source "great stuff", which annoys me quite a bit. I live in the part of the world where shipping costs from Amazon usually are 2x the price of the product :D I know, its a first-world problem, but still.. I've done quite a bit of research into the "can" types of foam I am able to get hold of, and the best one I've found so far is PUR from Tec7 with a water absorption rate of 1% volume (https://tec7.com/storage/files/7d5b...6b42/purnovatechtecv2020-03-05-09-42-36en.pdf). Most other foam products have a lower rate of closed cells, and well, act more as a sponge I guess.

XPS vs Polyiso & "Foil Face Polyiso"

View attachment 79722

XPS is direct buried against foundations with soils - They do not do that with Polyiso

Here is a temp R Value XPS wins out on Polyiso in the cold - but not in the heat - If you plan on being in warm areas the roof and walls can get quite hot & especially if you have a dark van paint job.

View attachment 79724

Here is more on the XPS vs Polyiso if you care to read the attached file pdf.
Thanks for the reading material. I think, the PDF you linked me, I've read through it before, and thats the one that got me on the idea of using XPS over alternatives like polyiso. Also, as I can see from the table, XPS still performs fairly well in high temperature, although not as good as polyiso, so I am also considering using XPS in the whole van.

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Discussion Starter · #29 ·
I would not use XPS in walls or ceiling because the max service temp is 165F and these areas could see temps in this area on rare occasions. DuPont (or DOW?) have lots of cautions on their website about keeping XPS from getting to hot - like don't leave it outside in the sun with the black lettering facing the sun - its not a fictional problem. As RV points out XPS is great for the floor, which won't see high temps.

On the insulation test I did under quite humid conditions the Polyiso did not pick up any water weight (sample weighed before and after to within a gram). So, XPS is no doubt better on moisture resistance, but Polyiso is probably good enough? People use Thinsulate and Wool, which are very permeable to water vapor, and I've not heard any horror stories from them about moisture problems.

The R value per inch of Poliso does go down with temperature, but it starts quite a bit higher than XPS and the crossover point where the Polyiso R value drops to the same value as XPS is quite low - about -10F outside temp. There are test data on the Building Science site on R value of Polyiso vs temperature. Its important when looking at this data to remember that the temperatures in the plots are the mean temperature of the insulation, so, if the outside temp is 0F and inside temp is 60F, the mean temp is 30F (not 0F). Even at lower -10F temps, the R value of Polyiso does not plummet, it just gets a bit lower than XPS.

Thanks Gary, thats a fair point I missed in the process too. I've read many of the articles you have made on your website, keep up the good work! Its really helpful for newbies like me :)

I think I'll stick to my original plan then, polyiso and foam it is. I'm trying to make the van work in both cold and hot climates, but I guess thats a hard nut to crack. I was initially planning of filling every rib with expanding foam too, but I think I will use more mineral wool type of material, in case I need to pull som cables or take anything out at any point.

Another point on insulation I've not seen anyone cover in great detail yet, is the health side of it. I mean, I am going to live in the van full time for a year at least, so I'de like to live in a healthy environment, if thats even an issue. I guess some materials are better than others. Like, most expanding foams are very toxic until cured (at least according to the safety data sheets), but unsure about the long-term effect of relying too much on that sort of material?

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Discussion Starter · #31 ·
I did not do a lot of filling of the ribs/frames, but I did work with Thinsulate a bit on filling the ribs, and its pretty nice for that. You can use a flexible wire to hook the scrim cloth on the back of the Thinsulate and pull it up into the rib that way. Probably other insulations with a scrim that would also work.

I cannot source thinsulate from anywhere in my parts of the world, so I have to rely on other types of material. But I'm sure I'll find something I can stuff in there :)

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Discussion Starter · #37 ·
Thanks all for valuable input and ideas! There are indeed a lot of knowledgeable and experienced users in this forum :)

I used poly-iso for the floor, walls, and ceiling. On the walls and ceiling, it is glued in place and edge-sealed with a non-expanding spray foam (GreatStuff Doors and Windows).

In the doors and channels, I used a polyester batting product called Tyvek Thermawrap. It may not be available in your area, but it shows there are alternatives to Thinsulate. You want a material, like polyester, that is hydrophobic and will not compress or migrate over time from the vibration of driving. This is especially important when insulating inside doors that get slammed all the time. A spray contact-cement will help hold it in place.

@GaryBIS and others have also questioned the benefit of insulating small channels (roof ribs, etc). It is probably insignificant compared to the thermal bridging of the surrounding metal. It is probably better to focus on insulating the outside of those channels. However, thermal bridging is still evident on the bigger channels that I insulated inside. In cold weather, I see condensation on those exposed metal surfaces.
Thanks, I'll look more into what options I have in this regard. I've also seen the health concerns regarding different types of mineral wool, at least if not properly incapsulated. After all, I'd like to make a healthy living environment :)

I might also have to test my approach during the winter, and add a layer if it is not sufficient. For example, I'm planning on 25mm (1") Armaflex on the bulkhead and headspace section, so I guess I'll have to test this in practise to see if its sufficient (this is to save precious space, and also oddly shaped parts where its hard to fit solid insulation panels).

Regarding the ribs, all good and valid points. I'll make sure to cover all metal faces, after all, this is where most air is most likely to condensate first. My initial idea however, was that stuffing ribs with some sort of "soft insulation material" is a very quick and easy fix, if it adds any benefit that is.

Thank you for the detailed and insightful reply. May I ask why it is that you don't recommend any of the mineral wool of fabric types of material? Is it due to the fact that it will be "sandwiched" in between two vapor barriers, effectively?
Many reasons - But primarily due to the air transfer (think moist air & look at @GaryBIS tests). Hydrophobic or not dew can collect when air reaches the dew point. Also even Nasty Asbestos is safe when incapsulated 😳 - Whatever you believe in regards to friable “fiber shedding materials” fiberglass & mineral wool are at best uncomfortable to breath & @ worst cause health issues.

For example, unlike to roof ribs (which are quite small), the side ribs in the walls are quite big, and would leave a huge heat bridge if untreated. I will run conduit and cables through, but some are big enough to consider other types of "filler" material than spray foam I guess. Or at least, I am considering it. I consider “Spray Foam” a superior product than the others - So I won’t use them cause I can get my hands on “Spray Foam”

As for the foam, I am also not able to source "great stuff", which annoys me quite a bit. I live in the part of the world where shipping costs from Amazon usually are 2x the price of the product :D I know, its a first-world problem, but still.. I've done quite a bit of research into the "can" types of foam I am able to get hold of, and the best one I've found so far is PUR from Tec7 with a water absorption rate of 1% volume (https://tec7.com/storage/files/7d5b...6b42/purnovatechtecv2020-03-05-09-42-36en.pdf). Most other foam products have a lower rate of closed cells, and well, act more as a sponge I guess.

I would have to research the Tec7 as I am not familiar. If you can find a “spray foam” that will stick, has a good R value, & will not harm you with off gassing then I would use that.

Thanks for the reading material. I think, the PDF you linked me, I've read through it before, and thats the one that got me on the idea of using XPS over alternatives like polyiso. Also, as I can see from the table, XPS still performs fairly well in high temperature, although not as good as polyiso, so I am also considering using XPS in the whole van.

That choice would depend upon intended use - location & weather/climate; for me I want Polyiso in the walls & ceilings.

Mean Temp - doesn’t refer to “nasty” but “average”

How cold do you plan on using your van?
I might be reading too much into this though, who knows. Anyways, all of these polyethylene based products (adhesives and / or sealant products) like Great Stuff, as far as I can see are highly toxic (at least until cured). Now, having said that, I believe products made for indoors use obviously should be OK to use and not pose a health risk, even long term. But now, since I've been reading up on the safety data sheets on all these products (I'm probably the only one bothered to actually open these boring manuals :D), I've decided to go the route of some more environmental friendly and Isocyanate-free products. The downside of course is that they cost 3 times as much, but I'm willing to pay, at least for ease of mind. I'm probably being paranoid, this is the "no skills" part of me doing research of stuff I know little to nothing about, but I can live with being called paranoid just fine ;)

As for the insulation panels I've ordered aluminium face PIR panels from a Finnish company FinnFoam that make them for their saunas. If they can use it in their highly moist saunas, I surely can use it in my van :D

As for your other question. I will use the van for weekend trips to the mountains for skiing, and my more "long-term" plan is to quit my job and go around Europe for a year or two living in the van. So I wanted to prepare it, at least to a degree, to handle both hot and cold weather. When I say cold, it's not extremely cold, maybe -10degC give or take.

Thanks @GaryBIS 100% agree !!

Sometime I am in some “mean” weather 😜

Tonight we are in the (mostly uninsulated) Cabin & got the Propex & Martin Wall Unit running. Nov 9 & not much snow on the ground. Definately need to get this cabin insulated or I am gonna go broke buying propane 💸💸💸.

At least we have about R24 of mineral wool on the roof (floor & walls - none).
Maybe my math is completely wrong, but how do you get those extreme numbers? I mean, the PIR panels I'm looking at I'm looking at is rated to 0.022 W/mK. A thickness of 50mm should be around R=2,27? (0,05/0,022). My math is probably ****.. or maybe mineral wool is the way to go after all ;)

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Discussion Starter · #40 ·
Oh and also, in structural engineering we specify stainless or galvanized fasteners at all PT lumber.
Stainless fasteners should not be used to fasten to non-stainless metal, as it will cause the other metal to corrode when exposed to moisture.
Interesting. what types of fasteners are you suggesting I should use for PT wood then? I might just get regular wood for the rest of the van to avoid such headaches. Did not think of that.

We have rented RVs in Europe many times. While planning this build, be aware of the differences you will face in terms of shorepower (220V) and propane (tank fittings differ by country). Also, the PM's Chrysler engine and tranny are not common over there, so parts and service may be hard to find. The European Fiat Ducato (and its clones) don't have Chrysler engines and trannys.
As I'm already living in Europe (although not a part of the EU), the 230V is not going to be a problem. 110 would be the headache for me ;) I've also got the Ducato (hence the extra high roof, as apparently are not available in PMs), so I guess I'm set there too, although I have no idea about the engine. Its a 170hp diesel, thats all I know :)

As for the propane fitting, yes, I've heard that can be a pain too. I've not got that point in my planning yet, leaving that for later :)

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Discussion Starter · #43 ·
Remember R value ins US units is about 5.7 times greater than R value in SI units.

US R value is in: sqft - F - hr / BTU
SI Rvalue is in: sqm - K / W

I did do a test on the Armaflex type material - basically just like the test mentioned above for the other materials. My conclusion was that it looks like a good material. It insulates well, and did not absorb any measurable amount of moisture. Its so easy to bend around corners and curves - very nice to work with. Only downside I saw was the expense.

Aha, of course, that makes perfect sense :)

Regarding Armaflex, indeed it is more expensive, thats why I'm only using it for the curvy and hard to reach bits in the van. I was actually thinking of using a 50mm type in the roof, but I got a quote today from my local supplier, 600$ for 5m2 (whatever that is in square-feet). So thats a no! PIR all the way it is :)

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Discussion Starter · #46 ·
It's time for an update I guess. And I'm embarrassed about my lack of real progress, but I'll get it together now that I'm out of "winter depression". It's been the two worst months in as far as I can remember, only raining and really shitty weather, so I've focused on skiing and drinking :D Anyway, I've done quite some extensive research on electrical systems and how to build a bathroom, so I've made use of the last months to do research and planning. Hopefully that will help me speed up my build going forward.

Anyways, from last time when I was asking you guys questions about insulation, I'm now almost finished insulating the van. I've complete the PIR insulation and managed to source some Thinsulate which I stuff into all small spaces, pillars, ducts and so on. Its quite time consuming getting the insulation everywhere, especially the hard to get areas, where I've pioneered a "pull the insulation by a string" method I've developed. I've pulled thinsulate into all the door- and window frames, and every other possible place where there could be a thermal bridge. I've used Armaflex in the difficult places like inside the doors, wheel wells, etc. I might get some mineral wool in the end, for the big spaces, and seal it off properly, otherwise thinsulate will be quite costly in the end.

I also made to size cardboard batteries to help me design the garage space. Also, I've placed all the gear I will bring in the van in the garage space to see how much garage space I need, especially how tall the bed frame needs to be. Luckily it seems it will fit everything I need.

A few new mistakes I've made:
  • Installing PIR insulation first. I've now blocked off access to quite a few places where I'm now struggling to get the thinsulate in, like those semi-open wall channels.
  • Waiting with the framework and wooden structure until insulation is installed. Should have started with the wooden frames.. would have made things easier.
  • Waiting with cables until wooden frame and insulation is installed. Should have installed some conduit at least in the process, now its too late.
  • Non compatible plusnuts (tool was too small). Now I have many "spinning" plusnuts in the sockets. That is oh so annoying. Not sure how I will fix it though..maybe sikaflex to the rescue.

A few pictures follows :)

Next steps, I really need to pull some cables before its too late..

Anyways, sorry for the lack of updates, there will be more in the coming months. Its finally above zero outside, so its slightly more comfortable working on the van :)

Bumper Automotive exterior Gas Font Auto part

Luggage and bags Bag Grey Backpack Gas

Motor vehicle Bag Luggage and bags Backpack Comfort

Wood Architecture Font Line Tints and shades

Shipping box Wood Rectangle Package delivery Gas

Automotive tire Architecture Floor Composite material Ceiling

Automotive tire Tire Motor vehicle Tread Automotive design
Tableware Sky Liquid Drinkware Beer

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Discussion Starter · #50 ·
There are plenty of ways to hide them before the walls go up. I intentionally didn't hide mine before insulation, so they were reachable, in the event of as problem.
Yeah, I'll figure something out. It was just frustrating when my master plan with pre-pulled conduit all of a sudden did not work out as I imagined it :) Todays lesson, try and think more than one step ahead :D
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