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Serious Insulation - And we're not talking about Reflectix here...

32K views 86 replies 27 participants last post by  FishHog 
#1 ·
So, so many videos on YouTube show people gluing Reflectix to every exterior and some interior surfaces of their van. No, this is not the way I'm going. It doesn't make sense for many, many reasons. To try and convince me otherwise is a complete waste of time.


Moving on... For the foreseeable future, I will be in a cold climate. Where I'm based I can expect winter temperatures down to -30°C [-22°F] or so, but cold like this is rare and doesn't usually last for more than a week or two at most. Average/typical is more like -10°C to -15°C [14°F to 41°F]. But I think you'll agree that with these temperatures heat and insulation is important if you want to be comfortable. Summer will be more of a challenge. Average "hot" sits around 25°C to 35°C [77°F to 95°F] and I don't tolerate heat well. I don't intend on spending a lot of time inside when the sun is beating down on the van's exterior.



I've also seen lots of people shoving insulation batts into every possible nook and cranny of their rather complex sidewalls and ceiling structures. I don't think I want to do this either, both from an insulation efficiency standpoint, and the time and effort involved. What's left? Well...


I'm thinking that I can tolerate some lost space on the inside to make things easier and possibly better. I'm thinking to basically build an insulated box inside the van. There would be a few ways to accomplish this. First would be to build and attach the insulated floor, then a semi-structural insulated ceiling, then build flat insulated structural walls that attach between the floor and ceiling. The wall between the cargo area and cab will also be insulated to the same extent. The order could be changed around a bit to accommodate different building techniques. One benefit that I see is that there would be free-flow of air around the van's metal interior panels. This should keep mold and moisture from building up without anywhere to go.



This could be done with a variety of materials, but I was thinking to focus on expanded polystyrene board (and/or poly-iso), softwood lumber, and/or plywood. This envelope would be just about air tight, so I'd also be planning to build in a small heat recovery ventilator (air exchanger) in addition to the vented propane furnace that would supply heat.



The thing is, I haven't seen anyone do this. Why not? It's been making a lot of sense to me.
 
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#3 · (Edited)
I installed cedar planks on 2x2 studs with an inch and a half of polyiso between the studs for the walls and a semi dropped ceiling.

this blog page was my guide:

https://www.instructables.com/id/Cedar-paneling-for-van-interior/

I also built front and rear bulkheads with plywood, Cedar planks and one inch of polyiso

my floor is a inch of polyiso and 3/4 inch plywood.

Built for christmas time family visits to northern minnesota and 100 (F) degree very humid Gulf of Mexico summertime heat.
Warm and toasty in winter, And it stays inside around ambient air temp in the summertime. (No ac yet.)
 
#11 ·
I installed cedar planks on 2x2 studs with an inch and a half of polyiso between the studs for the walls and a semi dropped ceiling.

this blog page was my guide:

https://www.instructables.com/id/Cedar-paneling-for-van-interior/

I also built front and rear bulkheads with plywood, Cedar planks and one inch of polyiso

my floor is a inch of polyiso and 3/4 inch plywood.

I do like the idea of cedar all around. How do you find your interior space with the walls and ceiling framed out like that?
 
#4 ·
Making a thick walled insulated box, like a giant styrofoam cooler, in your van is probably the best way to insulate for extreme temps, but remember that you'll need to be able to breathe. Maybe make the vents low so heat doesn't get out.
 
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#5 · (Edited)
You are right about nooks and crannies. Waste of time, materials, and effort.
https://www.fordtransitusaforum.com...25-filling-small-channels-insulation-why.html

Polyiso sheets (R-Max at Home Depot) covering the larger van panels that have Thinsulate attached to the expansive skin surfaces might be along the lines of what you have in mind. This would provide higher R-values using layers of easy to work with materials. What remaining sections that can't easily be covered that way can have a barrier (speaker carpet, hull liner, etc.) attached, possibly with a layer of thin insulation (closed cell foam sheets, CS150 Thinsulate, etc.) as a thermal barrier, to reduce heat loss through the bodywork at those points.

Block any heat path between the warm cabin air and the cold, cruel world.
 
#6 ·
You might consider one (recommended) or more layers of 3M Thinsulate(TM) SM600L and/or SM400L with Low-E behind the ceiling panel. We have helped a lot of DIY and professional van builders in Alaska, Canada and the Rocky Mountains insulate their vans. Their feed back regarding performance in cold weather has been nothing but positive. We hear the same enthusiastic feedback from our customers in hot sunny climates.

It's not that hard to make a van comfortable without turning it into a rolling cooler.

All the best,
Hein
DIYvan.com
 
#7 ·
I've seen people use a froth pak from 3M. Its a spray foam. Can be put on very thin, but has amazing properties. It's moisture blocking, so it won't hold moisture and rot any metal. It's the same stuff you spray in your house. $200 bucks would get you a lot of foam to spray into all the nooks and crannies. Then use a wood or vinyl panels for the walls. I would be more inclined to use a vinyl wall board, in approximately 1/8 thick, sort of like comes in a motorhome.
 
#10 ·
I've seen people use a froth pak from 3M. Its a spray foam.

Maybe it's just me, but I think coating the inside of an almost brand new van with spray foam is a good way to significantly reduce the resale value. Another criterion for me is the ability to remove stuff related to the conversion without leaving a really big mess behind. This isn't to say I'll balk at cutting holes or gluing where indicated, but it will always be in mind to be the least invasive I can be while still accomplishing my goals.
 
#9 ·
I mentioned in the first post that I'll be running a vented propane heater. I already have a Propex HS2000 for the purpose.


Having better than average insulation will help conserve fuel in the winter, and may help excessive heat build-up in the summer.
 
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#12 ·
I'm also opposed to the idea of sprayfoam. But I'm sure it has it's uses, or is more within the skill set of some people.
I don't think there is any good substitute for some rattle-trap on the big panels and thinsulate in the walls and ceiling (and maybe floor). There might be cheaper ways to go, but performance won't be the same.
Doing that, and adding another inch or so of polyiso on the interior, in turn paneled with something durable, should make the interior of a van VERY insulated.
 
#13 ·
I’d be tempted to build a plywood box. No studs. Full insulation glued to the outside. It could be glued up in place, including the "lid". Brackets on the inside could reinforce glued corners.

I’m getting claustrophobic…
 
#14 ·
For temporary use, making a giant "cooler" that slides in from the rear doors wouldn't be a bad idea. Like a camper for a pickup, except it goes on the inside of a van instead. Too bad the Transit rear doors don't open all the way to the ceiling, that's a lot of wasted space if you build a slide-in box.
 
#15 ·
I had considered something like this, but instead I'm focusing on more of a "knock-down" or "flat pack" approach. This enables making it larger than any opening, and manageable by one person.
 
#17 ·
Do you have some pictures or video showing details and overview?
 
#20 ·
Stick-frame construction uses 3-1/2" to 5-1/2" pink fiberglass. No aluminum bag but lots of kinky vapour barriers.
 
#21 ·
There was a guy that camped in Alaska for 15 years in a van , he said you don't need any insulation at all on the floor.
On a very cold day try sitting in the back of your van for about a hour with a infra red temp gun , pull the trigger and keep it held in and sweep it very slowly and take temp measurements of all the surface areas , it tells you very interesting things , ,,,,like were to put more insulation
 
#23 ·
There was a guy that camped in Alaska for 15 years in a van , he said you don't need any insulation at all on the floor.

You're probably thinking of Bob Wells. Very opinionated and has quite the following. I don't agree with everything he preaches though.



On a very cold day try sitting in the back of your van for about a hour with a infra red temp gun , pull the trigger and keep it held in and sweep it very slowly and take temp measurements of all the surface areas , it tells you very interesting things , ,,,,like were to put more insulation

Or I could just borrow the FLIR camera from work. ;)
 
#27 ·
I mentioned including a heat recovery ventilator in my initial post. With how air tight I plan on making it, this would be very important to avoid inadvertent death.
 
#28 · (Edited)
Eiko
"What did your IR gun tell you about insulating the floor?"

Note that I have a uninsulated floor except for carpet padding and carpet.

Weather is 32 f degrees, thermostat set to 66 f degrees
Heater output vent is located 5 inch above the floor.
Up around the ceiling is 80 degrees , pointing at celing ribs i get 76 degrees ,,ribs aren't insulated yet.
Top of the wall is 71
As you go down the wall it gets colder and colder until I reach the floor where the temp is 60 .

So I know that the heat rises and pools in the ceiling because it's pretty obvious when I stand up you can feel the warmth , I think he may have a point as the hot air rises and gets trapped in the ceiling , some one could say the floor is cooler at floor level because you lost the heat out the floor because of non insulated floor but if that is true how come the heat in the ceiling didn't escape out the floor too?

I think I need a ceiling fan too push the warm air back down and circulate it.
 
#30 ·
All the Boeing airliners I worked on used 1.5" 3M insulation, in a bag. I do not know what "type". It was pink. Airline companies are all about efficiency. RV conversions? "Not so much". This Form might consider a contest to find out who has added the most weight to their conversion.
 
#31 ·
Frankly, what Boeing does is inconsequential to me and my own build. Not only is their budget orders of magnitude higher than mine, I have to assume that build cost and weight savings are higher priority to them than insulation value. There has to be a huge amount of waste heat readily available from those huge jet engines. But I'm just speculating.


I'd have already purchased a prefab conversion if they did a decent job on insulation and stealth, but the builders haven't seen a market for that just yet.
 
#34 ·
I've done serious insulation

hokay so...I used 3.5" rockwool from Lowes and 1/2" inch rigid insulation from Home Depot with a shiny foil face. I did stuff and fill all the crevices in a couple hours by cutting the rock wool into smallish cubes then stuffing them into various holes. Smaller cubes move more easily through the spaces than larger continuous sections (learned from trying). Once you get into the rhythm it really doesn't take long. I don't know if it makes much difference or not, my thoughts were to fill the air cavities.

I used full size batts of rockwool in the spaces between the ribs on the roof and along the walls. All of this insulation is held in place by using the foam board as the next layer. The foam board is held in place by 1x3 boards that make an internal frame and are pressing outwards against the foam boards.

My floor is insulated with 1/2" foam board between all the ridges and a 1" foam board on top of that. My subfloor is 22 guage sheet metal that has about 1/4" space between the metal of the van wall. I plan to put in a carpet so I can walk around barefoot without it feeling too cold but for now I just wear wool socks and can stand on it without my feet feeling cold. Standing barefoot on the subfloor is cold. The internal 1x3" frame presses down on the floor and up against the roof. It is a floating floor so hopefully it stays in place. I don't actually plan to drive much.

I built a wall along the back that blocks the rear doors and insulated it similarly. I couldn't figure out a good way to insulate the doors. That rear wall has hinges on the roof and in the summer I can open the rear doors of the van and pull the wall upwards (holding it in place with a large stick for now) similar to the rear hatch on my Subaru Outback. The rear wall has two windows that open for light and air.

I built an internal wall that crosses the van just to the rear of the sliding door and it is similarly insulated. This wall has a doorway but I have not built the insulated door just yet. I have a section of rigid insulation that I put in place at night when I go to sleep and remove it when I leave in the morning. All the foam boards are taped together with aluminum foil duct tape. My living room is most definitely a "cooler." With the exception of my temporary door, it is air tight and remains about 10 degrees fahrenheit warmer than outside when I am in it at night. The other side of the wall will be the garage/mud room.



I have about 67" from wall to wall along the floor, a bit more in the middle, and I don't know what the width of my ceiling is in the living room. It is around 8'6" from interior wall to rear wall along the floor. I think it is maybe 6'3" from floor to ceiling in the the middle of the floor, not real sure what my wall height is.

I don't have heat yet but I will likely buy a cubic mini wood stove. Once the summer comes around I'll cut a giant hole in the roof (maybe 24"x24") and make a skylight/vent/roof access hatch. Still have to put in an HRV or ERV and make electricity to run it. It's a work in progress.

I uploaded some photos (there are more but I hit the limit for what I can upload in a single post), hopefully they help for visualizing the inside of Babe the Big Blue Box. The major accomplishment of this build so far is that there is not a single thermal bridge from my living room to the skin of the van. It is not uniformly insulated but it is pretty good. I tend to live on cold places...2018 Long/high roof/T250. I also don't log on to this website much so I apologize if I don't respond frequently if at all...
 

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#36 ·
My living room is most definitely a "cooler." With the exception of my temporary door, it is air tight and remains about 10 degrees fahrenheit warmer than outside when I am in it at night.
Your temperature differential is quite interesting. Our van is well-insulated in the ceiling and lower panels, but doors, cab, and full windows all around are uncovered and uninsulated. Uncovered metal is everywhere for lots of thermal bridging. We can pretty reliably predict that in the morning, after a cold night with no auxiliary heat, the inside temperature will be about 10°F warmer than outside.
 
#35 ·
Good stuff! Your layers are similar to what I have in mind. I have more questions about it when I'm back at a real keyboard (not a phone).
 
#38 ·
A lot of interesting ideas here. Here's my two cents.

We built for far north winters and southern summers. In fact, I'm typing this from Green Point in Gros Morne National Park, Newfoundland where we are camping for the week. It has been a low of -15C (5F) and we are super comfy. We live in SC, USA, so we need to be able to handle high summer temps.

Here's what we did:

Floor: spray foam to adhere 1" polyiso sheets to the steel. Top that with 1/2" plywood.

Walls: spray foam (1" - 5" depending on location) topped with Reflectix.

Overhead: 2" spray foam topped with 1/2" polyiso sheets.

Rear and sliding doors: Reflectix and cover with a heavy sleeping bag.

As I mentioned, we've been super comfortable and have had no issues with condensation. I would 100% recommend this route for your application as it conserves on space inside and meets your requirements.

Check us out at https://www.instagram.com/thevanjob/ to see pics and videos.
 
#41 ·
As a pragmatist, I just checked my aviation/RV insulation posit. With Winnebago. I missed the price point on the aviation type insulation because Winnebago is using the same/similar material, but the material is recycled. Cheaper. Sorry folks. I'll try to do better next time. My bad. Evidence in opposition is always gratefully accepted.
 
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