That picture looks shockingly familiar to my polyiso installation, right down to using a foam gun. The polyiso does work great and goes up easily, especially if you have a helper cutting it for you. Should also note that many pieces are side to side mirrors, so once you get one side cut, it's a template for the other side.

 

There's a lot of nonsense floating around about foam insulations. Mostly phony scare stories about off-gassing etc., which is way overstated and after doing some research, I found a lot of it very misinformed. One website claimed "studies" show polysio doesn't insulate at certain temperatures, which I just found too hard to believe. Seems the current fad right now is to use 3M Thinsulate or Havelock wool, which clearly has drawbacks, one of which is mice love to nest in the stuff.

I went with spray foam, and I'm very satisfied after doing the readings with my heat gun. I used Owens-Corning XPS on the heated floor because of its hardness and density. Polysio would have been a great alternative in all cases. For me, getting an insulation that adheres to the van tightly, acts as an excellent moisture and sound barrier, and is easy to install directed me toward spray foam. I also used the stick-on foam in certain places, though time will tell how long it actually sticks to the sheet metal.

 

So much of the insulation choice depends on the climate and use plan.

Insulation for a hot dry climate is really very different than a PWW wet climate vs a very cold 'real winter" climate.

Every insulation R value is temperature dependent, some perform better in cold ( - 30 C ) and some in hot ( as in 50 - 60 C skin temps. )

Nearly all insulation thread discussions end up confused by not considering these differences.

 

So much of the insulation choice depends on the climate and use plan.

Insulation for a hot dry climate is really very different than a PWW wet climate vs a very cold 'real winter" climate.

Every insulation R value is temperature dependent, some perform better in cold ( - 30 C ) and some in hot ( as in 50 - 60 C skin temps. )

Nearly all insulation thread discussions end up confused by not considering these differences.

There will never be a perfect insulation specification for all climates/time durations. There are many insulation methods that end up being a disaster without proper consideration of their qualities in varying extreme heat/cold and humidity. Yeah, give me wool/denim in FLA? Yeah, it is hot as Hell for the the better part of the year in the SW, but it is a dry heat(as they say). @GaryBIS might critique/correct my opinion which I welcome.

 

Hi,
If you are interested in some reading to put you to sleep - try the attachment.

Its a cut at ratings for each of the common camper van insulation types (Polyiso, Thinsulate, Wool, XPS, Fiberglass and Spray Urethane).

I'm going to put it on my website and would appreciate any comments, corrections, ...

Each insulation is rated in these areas:
Does it hold up to the van environment
Does the insulation hold up OK to the vibration, temperature and humidity environment of a camper van.

Adverse health effects on humans
Does the insulation have any known bad health effects.
Outgassing, loose fibers, …

How good an insulator - R value per inch
Is the material a good insulator?
What is its R value per inch?

Moisture/humidity handling
How does the insulation material handle water vapor and condensation?
Will it result in mold, rust, condensation problems?

Does the insulation absorb water?
Does the insulation material itself absorb water into its fibers?

Cost
How much do the insulation, installation and shipping cost – not counting your labor?

Install labor and difficulty
How hard is the insulation to install?

Ease of removal
You may have to take the insulation out some day. How difficult will that be?



Gary

 

Other than the holes I put in the van (feed-throughs, windows) everything is easily removable, including the insulation (Thinsulate) which, in fact, I had to remove since the !@#$%^% dealership dragged the passenger side of the van across a column for it's first oil change... It is true that in cold, the thinsulate insulation allows condensation on the van wall and that has shown up over the last four years as lightly corroded sheet metal screws used to hold down panels, etc. OTOH it does dry out easily.

Another consideration, @GaryBIS , is the overall envelope thermal value. It seems, to me, pointless trying for R7 walls when 15-20% of the van surface is R1. For cold climates, it is far easier/cheaper to get a 4kw heater! For hot climates? Maybe the effort is worth it, particularly with a 140f roof under those solar panels.

 

Other than the holes I put in the van (feed-throughs, windows) everything is easily removable, including the insulation (Thinsulate) which, in fact, I had to remove since the !@#$%^% dealership dragged the passenger side of the van across a column for it's first oil change... It is true that in cold, the thinsulate insulation allows condensation on the van wall and that has shown up over the last four years as lightly corroded sheet metal screws used to hold down panels, etc. OTOH it does dry out easily.

Another consideration, @GaryBIS , is the overall envelope thermal value. It seems, to me, pointless trying for R7 walls when 15-20% of the van surface is R1. For cold climates, it is far easier/cheaper to get a 4kw heater! For hot climates? Maybe the effort is worth it, particularly with a 140f roof under those solar panels.

Hi Larry,
Thanks for taking a look!

I guess a lot depends on the way you plan to use the van. If you know its going to be a three season van for a moderate climate, then its important to have insulation, but it does not have to be excellent. But, its hard to guess how you are going to use the van over 20 years of life and maybe investing an extra day or two of build time and an extra couple hundred bucks is worth it just in case you want to become a ski tripper or arctic explorer or go or wander down to Patagonia via the tropics. Its tough to add insulation after everything is in.

A lot of people are putting in double pane windows now days - I think I would on a next van. And, you can get regular windows up to R3 to R4 with very crude shades. Also pretty easy to do an insulating curtain between cab (with all the glass) and back of van.

I really like the way @Dennis CampMaker insulated his latest van.

Walls: Two layers of 1 inch Polyiso where the wall frame thickness allows it without losing any internal space.
So, R13 walls in lots of places with no loss of interior space.

Nice job with the Great Stuff

Ceiling: Fur down the ceiling ribs with pine board which allows the usual layer of 1 inch Poliso plus a layer of 1/2 inch polyiso and also makes it easier to install the ceiling panels. Only lose half an inch of head room.
R9+

Cab Divider: Wool blankets with snaps for quick attach.

R6 window curtains, which I don't have a picture of.

Thinsulate to fill curvy places.

Thermal bridging protection?

These extra steps likely cut the heat loss (or heat gain) in half or more. Probably added a couple days work?

Just thinking about it makes me want to go build a new van

Gary

 

I also used 1" polyiso and doubled it below the belt line. I wish I'd put 1/2" furring on the ceiling ribs to facilitate that extra 1/2" of polyiso. Although, I could only find 1" poly-iso at the time.

I used a generic pro-gun from Amazon for GreatStuff Foam Door and Window. It worked great, and I went through a ton of foam with it. It wasn't cheap, but I was thorough. I didn't spend a lot of time getting a close fit around the edges of the poly-iso. Instead, I filled the gaps with foam. This thoroughly sealed the edges preventing moisture intrusion behind the poly-iso. I also wish I'd known about thermal bridging. But I'm no where near ready to build another one. Having way too much fun with this one.

 

Gary, I like the document. The only thing I would quibble with is the XPS use temps. Extruded polystyrene is made of PS which has a Tg of 100 C, the softening point. It's clearly fine up to 190F as it's used extensively in hot beverage drinking cups, where you do get 190F. Given the non structural nature of this application, it will work in the sides and top of the van. Even a black van in the sun doesn't get that hot.

I did use polyiso in my walls and ceiling, cost difference between it and XPS was almost nothing, better R value and it's got a foil face if there are radiant concerns. I'm actually using a thin 1/2" thinsulate over top of the polyiso for sound and final conformability.

 

Gary, I like the document. The only thing I would quibble with is the XPS use temps. Extruded polystyrene is made of PS which has a Tg of 100 C, the softening point. It's clearly fine up to 190F as it's used extensively in hot beverage drinking cups, where you do get 190F. Given the non structural nature of this application, it will work in the sides and top of the van. Even a black van in the sun doesn't get that hot.

I did use polyiso in my walls and ceiling, cost difference between it and XPS was almost nothing, better R value and it's got a foil face if there are radiant concerns. I'm actually using a thin 1/2" thinsulate over top of the polyiso for sound and final conformability.

Hi,
Thanks for taking a look at it.
Good point about the drink cups.

They do quote a max service temp of 160 to 165 depending on the source...

They have this long list of cautions about XPS and sun exposure...

I left a piece of EPDM rubber sheet on a sheet of XPS in a solar batch water heater I was building - it had a nice sort sculpturing effect

I built a little test rig to test how hot a van skin might get with a piece of XPS glued to the back of it - just waiting for a hot sunny day to see what the temps come out to and whether the XPS actually shows any damage even when the temp goes above 160F. Warmest we have had so far has been high 80's.
I'll report back however that comes out.

right face is alum sheet (half black half white) with XPS glued to it with Great Stuff foam. Will log temperatures in and on metal and solar input - when we get a good day.
It looks a bit rough, but its all scrap (aged

Gary

 

XPS, polystyrene has very poor weathering in sunlight. Definitely should not have prolonged exposure to sunlight. We do a lot of outdoor weathering and black panel max temp is about 170F.

 

I'm doing a lot of insulation right now, so here are a few more photos that relate to this thread. When you do a lot of climbing into the back door, steps can be helpful.

 

I'm adding the second layer (which is 1/2 inch) to the ceiling. Even though it is overkill, the track saw works really well to cut insulation. Sheet foam scraps work great for a cutting surface.

 

I'm adding the second layer (which is 1/2 inch) to the ceiling.

The second layer doesn't touch the sheet metal. I don't think it has to be polyiso, xps is easy to find.

 

Sometimes you have to look very closely to find polyiso in the sheet foam specifications. I normally purchase R-Matte at Home Depot, but one time I tried to get at least a form of polyiso at Lowe's and I couldn't find any. They only had EPS, which I didn't want.

 

Here are 3 photos showing the progression of layers in the lower side wall. Because of the sheet metal creases, I cut smaller sections of foam for the first layer and then larger foam for the second layer. All layers have spray foam around the edges.

 

This is the finished ceiling with R9 insulation. I will cut extra spray foam off so the panels can lay flush across the ceiling.

 

This is what some foam looks like after being in boiling water for a few minutes. I can't find the before pictures but I recall the polyiso and xps had about the same shrinkage.

 

Since a good number of ProMaster Forum members have used polyiso foam board to insulate your vans, are any of you aware of problems that have developed over time with using this method for insulation?

 

Only where I didn't cover the raw edge with high temp expanding foam or good quality HVAC aluminum duct tape. I see a very small amount of shrinkage in the exposed cores which are occasionally subjected to direct sunlight. I am not disappointed at all. Eight years going, from 20 below to 118.

I don't care how much insulation you have in extremely hot or the combo of hot and humid outdoor conditions you have, could have minutes(Death Valley Dumb Trip) to a few hours before everything comes to an equilibrium. Best catch it early in the morning.

 

How do folks deal with upgrades, new wiring, body damage? The permanent nature of the insulation put me off, but maybe that isn't such a big deal?

 

I always leave channels for the wires when I run them. That way I can add or change wires in the future. I’m not sure about body damage. If it wasn’t a large area, it would be very possible to scrap off the foam and panels.

 

I would like to chime in about my semi-permanent install of my polyiso panels. I did not use Great Stuff to adhere them because I was too impatient to brace the individual panels while the foam cures. I installed all my panels with 3M 90 spray foam and the 1” panels are still up years later and firmly attached. They even conformed to the slight curbed roof.
I recently had to remove a polyiso ceiling panel and it came off without breaking the foam, leaving only spray adhesive residue behind.

I think using 3M 90 spray adhesive is a valid alternative to using Great Stuff. I still used Great Stuff around the perimeter.

 

I think using 3M 90 spray adhesive is a valid alternative to using Great Stuff. I still used Great Stuff around the perimeter.

I tried to use 3M 90 spray and it didn’t work as well for me as Gaps and Cracks, but I'm glad it worked for you.