Ram Promaster Forum banner

161 - 180 of 190 Posts

·
Registered
Joined
·
1,812 Posts
I don't advocate senselessly and deliberately destroying the environment. Actually, it makes my blood boil to see degenerates flicking cigarette butts out of their car, or to see even a candy wrapper in the woods.
However, isn't it a little silly to pick and choose which materials to avoid or feel guilty about using when there really isn't a single material or process we use in this day and age that isn't harmful to our health or environment? Whether in it's creation or disposal?
Even the products that people use because they think are "green", probably do more damage in their manufacturing and shipping processes than they do good.
Anyway, the amount of methane released by the amount of sheep it takes to line your van with wool, is probably equal to the amount of greenhouse gas released from a single sheet of 1" XPS. Not to mention this stuff all gets shipped around in the same diesel trucks with the same rubber tires, with the same drivers throwing styrofoam cups and cigarette butts out their window.
 

·
Registered
Joined
·
1,198 Posts
I don't advocate senselessly and deliberately destroying the environment. Actually, it makes my blood boil to see degenerates flicking cigarette butts out of their car, or to see even a candy wrapper in the woods.
However, isn't it a little silly to pick and choose which materials to avoid or feel guilty about using when there really isn't a single material or process we use in this day and age that isn't harmful to our health or environment? Whether in it's creation or disposal?
Even the products that people use because they think are "green", probably do more damage in their manufacturing and shipping processes than they do good.
Anyway, the amount of methane released by the amount of sheep it takes to line your van with wool, is probably equal to the amount of greenhouse gas released from a single sheet of 1" XPS. Not to mention this stuff all gets shipped around in the same diesel trucks with the same rubber tires, with the same drivers throwing styrofoam cups and cigarette butts out their window.
Exactly the way I feel about it RnR !!

Sometimes when we trace the “green” like “fly ash” in concrete or electric vehicles that are charged by coal fired electrical plants the “green” changes some colours in my old eyes.

If I can protect the environment at zero cost to me & the “Science” is good then of course I will. But if there is a cost then I have to consider as much correct info I can get my hands on. In the case of the EXP board I choose selfishly, & would probably do it again.
 

·
Registered
Joined
·
1,556 Posts
Hi,
Did not mean to stir the pot with the comment about the greenhouse gas problem with XPS.

Agree that a couple sheets of XPS used in a van is not going to have any significant effect.

They rate greenhouses gases with GWP. CO2 has a GWP of 1. The gas used as the blowing agent for XPS has a GWP of 1400 -- yes 1400.
This becomes an issue mostly in home construction where many of the people building highly insulated houses are not only trying to save energy but also trying to reduce the homes production of greenhouse gases by using less fuel for heating with more insulation. But, with the high GWP of XPS it can take 50 years to get to a breakeven point on greenhouse gas production where the reduced CO2 emissions due to using less heating fuel just balance the greenhouse gas emissions from the XPS as the blowing agent diffuses out to the air. Alex Wilson pioneered the work on this, and his findings are not in dispute -- even the insulation industry acknowledges that a better blowing agent must be found and they work working on it.

Polyurethane spray foam insulation also uses a blowing agent with a high GWP (1040), so I contributed my bit to worse climate change when I used it to insulate my van. It just seemed for the small amount involved and the perceived advantages it was worth it.

But, Polyiso has a low GWP, and I'm guessing even with the sheep farts that wool is also good -- especially given that the sheep are not raised mostly for the wool insulation.

Gary
 

·
Registered
Joined
·
295 Posts
Is it xps that has a large fall off in insulation properties as it gets cold?

At one time I looked at the charts very closely and was surprised to see that at some temperatures, 3/4 baltic birch wasn't so much worse than some of the other commonly used insulation materials.
 

·
Registered
Joined
·
1,812 Posts
Haha. No pot stirring. People bring up trying to "be green" a lot. I see no reason we can't have a conversation about it, so long as no one freaks out.
Your point about XPS off-gassing and negating the reduction of greenhouse gas via reducing energy consumption,....speaks to how I see the situation.
People are either well intentioned and unaware, or just fulla crap.
A little of both, if I understand psychology.
The core motivation is to save money over time, way more than protecting the environment. At the end of the day, most of the theatrics I see about being green, adds up to little more than a hollow sentiment on the consumer's part and a marketing scheme by product manufacturers. Truly being green and doing anything that would actually make a dent would require far more effort and sacrifice than most people in a 1st world country would truly be willing to suffer.
You humans are a curious bunch.
 

·
Registered
Joined
·
1,556 Posts
Hi,
So, this is the promised followup on how much water various samples of insulation absorb over a full day immersion.
I added the results for a longer soak (23 hours) and for the GreatStuff foam and just to have a material most of us are more familiar with, I did a 2 hour soak of a piece of 3/4 inch plywood. The new data is edited into the original post below...

Hi Baxsie,
Your writeup brought out the Boy Scientist in me -- so, went out to the shop and dug up all the insulation samples I could find, cut them down to a standard size of 8 by 11.5 inches, weighed each sample on a postage scale, soaked them in a bucket for 2 hours, dried them off and weighed them again. Results below, but samples are back in the bucket for a longer soak.

The samples vary in thickness, but the surface areas are close.
All of the samples were immersed in a 5 gallon bucket and weighted down such that they were fully under water. The water temp was 58F. The water depth was 12 inches, so average static pressure pushing water into the insulation is about 0.22 psi. So, this is a really severe test for water absorption -- much more so than service in a van. But, it is similar to the ASTM test for insulation moisture absorption.
After the 2 hour soak, I took each sample out, shook the surface water off, and dried with a towel and then weighed.

The samples:
RTech EPS white styrofoam 1.5 inches thick
It has alum foil on one side, and a "polymeric film" on the other side to provide "excellent" moisture absorption protection.
Weight before = 43 grams
Weight after 2 hrs = 107 grams
Weight after 23 hrs = 116 grams

DOW XPS blue styrofoam 2 inches thick
No apparent films on the surfaces
XPS is generally acknowledged to have low moisture absorption
Weight before = 83 grams
Weight after 2 hrs = 83 grams
Weight after 23 hrs = 84 grams


Polyurethane spray insulation 0.6 inches thick ON STEEL
This is a scrap from one of my window cutouts from the van
It was sprayed from a two bottle kit from Home Depot (link below)
The inside surface of this develops a bit of a skin that may reduce water penetration and also makes it harder to dry off the surface moisture before weighing.
Weight before = 445 grams
Weight after 2 hours= 449 grams
Weight after 23 hours = 453 grams

Polyiso rigid foam board with foil faces -- 1 inch thick
This is the stuff a lot of people have been using to do their vans.
Weight before = 48 grams
Weight after 2 hours = 55 grams
Weight after 23 hours = 61 grams

Thinsulate from 3M -- 2 inches
Weight before = 44 grams
Weight after 2 hours = 225 grams (after wringing it out)
The Thinsulate literally soaks up water like a sponge as it is very porous. It is not meant in any way to stop moisture penetration, but it is said that the fibers do not actually absorb water. So, this test is not very meaningful for Thinsulate, but I had the sample and just decided to soak it along with the rest.

Great Stuff Pro Gaps and Cracks 1 inch thick
This was applied to a 8 by 11.5 inch piece of alum foil
Weight before = 37 grams
Weight after 2 hours = 41 grams

Plywood 3/4 inch exterior
Weight before = 647 grams
Weight after 6 hours = 862 grams

-------------
Thoughts and opinions on longer test...

XPS definitely the leader on not absorbing much water -- only 1 gram over 23 hours.

Polyiso gained another 6 grams for a total of 13 grams for 23 hours. As RD pointed out, A lot of this is probably getting in the edges of the sample, which have no foil facing. Since these are small samples, they have a higher ratio of edge area to face area than a large sheet would, so more realistic size sheets would likely perform even better. This seems like good performance to me when you consider how severe the test is and that the plywood sample gained 215 grams in 6 hours.

Polyurethane spray foam on steel sample
This is about 0.6 inches of spray foam sprayed onto part of a PM window cutout.
The spray foam only gained a total of 8 grams over 23 hours -- a bit better than the Polyiso. Also quite good I think.

Great Stuff Pro Gaps ad Cracks applied 1 inch thick to alum foil.
Showed a gain of 4 grams over 2 hours -- so, pretty close to the Polyiso sample.
The Gaps and Cracks (I guess) is made to fill larger cavities, and if you cut a sample of it and look at the cross section the bubbles are fairly large (1/4 inch ish) -- I suspect that the Great Stuff with finer bubbles would perform even better?
The Great Stuff seems to perform about the same as Polyiso, so it does not appear that its a moisture weakness in the Polyiso/Great Stuff combo a lot of people use.

EPS styrofoam still surprising to me how much water it absorbs. Reading about it a little, its made from styrofoam beads and while the beads are closed cell and do not absorb much moisture, the spaces between the beads do allow moisture penetration and this may account for the 60+ grams of water absorbed.

I cut each of the samples to see if the inside showed any sign of moisture or of an advancing water front. I did not see any sign of wetness on the sample cross sections except for the plywood. The Great Stuff had large bubbles in the cross sectional cut, but no sign of any moisture getting into them.


Gary
 

·
Registered
Joined
·
1,198 Posts
Hi,
So, this is the promised followup on how much water various samples of insulation absorb over a full day immersion.
I added the results for a longer soak (23 hours) and for the GreatStuff foam and just to have a material most of us are more familiar with, I did a 2 hour soak of a piece of 3/4 inch plywood. The new data is edited into the original post below...

Hi Baxsie,
Your writeup brought out the Boy Scientist in me -- so, went out to the shop and dug up all the insulation samples I could find, cut them down to a standard size of 8 by 11.5 inches, weighed each sample on a postage scale, soaked them in a bucket for 2 hours, dried them off and weighed them again. Results below, but samples are back in the bucket for a longer soak.

The samples vary in thickness, but the surface areas are close.
All of the samples were immersed in a 5 gallon bucket and weighted down such that they were fully under water. The water temp was 58F. The water depth was 12 inches, so average static pressure pushing water into the insulation is about 0.22 psi. So, this is a really severe test for water absorption -- much more so than service in a van. But, it is similar to the ASTM test for insulation moisture absorption.
After the 2 hour soak, I took each sample out, shook the surface water off, and dried with a towel and then weighed.

The samples:
RTech EPS white styrofoam 1.5 inches thick
It has alum foil on one side, and a "polymeric film" on the other side to provide "excellent" moisture absorption protection.
Weight before = 43 grams
Weight after 2 hrs = 107 grams
Weight after 23 hrs = 116 grams

DOW XPS blue styrofoam 2 inches thick
No apparent films on the surfaces
XPS is generally acknowledged to have low moisture absorption
Weight before = 83 grams
Weight after 2 hrs = 83 grams
Weight after 23 hrs = 84 grams


Polyurethane spray insulation 0.6 inches thick ON STEEL
This is a scrap from one of my window cutouts from the van
It was sprayed from a two bottle kit from Home Depot (link below)
The inside surface of this develops a bit of a skin that may reduce water penetration and also makes it harder to dry off the surface moisture before weighing.
Weight before = 445 grams
Weight after 2 hours= 449 grams
Weight after 23 hours = 453 grams

Polyiso rigid foam board with foil faces -- 1 inch thick
This is the stuff a lot of people have been using to do their vans.
Weight before = 48 grams
Weight after 2 hours = 55 grams
Weight after 23 hours = 61 grams

Thinsulate from 3M -- 2 inches
Weight before = 44 grams
Weight after 2 hours = 225 grams (after wringing it out)
The Thinsulate literally soaks up water like a sponge as it is very porous. It is not meant in any way to stop moisture penetration, but it is said that the fibers do not actually absorb water. So, this test is not very meaningful for Thinsulate, but I had the sample and just decided to soak it along with the rest.

Great Stuff Pro Gaps and Cracks 1 inch thick
This was applied to a 8 by 11.5 inch piece of alum foil
Weight before = 37 grams
Weight after 2 hours = 41 grams

Plywood 3/4 inch exterior
Weight before = 647 grams
Weight after 6 hours = 862 grams

-------------
Thoughts and opinions on longer test...

XPS definitely the leader on not absorbing much water -- only 1 gram over 23 hours.

Polyiso gained another 6 grams for a total of 13 grams for 23 hours. As RD pointed out, A lot of this is probably getting in the edges of the sample, which have no foil facing. Since these are small samples, they have a higher ratio of edge area to face area than a large sheet would, so more realistic size sheets would likely perform even better. This seems like good performance to me when you consider how severe the test is and that the plywood sample gained 215 grams in 6 hours.

Polyurethane spray foam on steel sample
This is about 0.6 inches of spray foam sprayed onto part of a PM window cutout.
The spray foam only gained a total of 8 grams over 23 hours -- a bit better than the Polyiso. Also quite good I think.

Great Stuff Pro Gaps ad Cracks applied 1 inch thick to alum foil.
Showed a gain of 4 grams over 2 hours -- so, pretty close to the Polyiso sample.
The Gaps and Cracks (I guess) is made to fill larger cavities, and if you cut a sample of it and look at the cross section the bubbles are fairly large (1/4 inch ish) -- I suspect that the Great Stuff with finer bubbles would perform even better?
The Great Stuff seems to perform about the same as Polyiso, so it does not appear that its a moisture weakness in the Polyiso/Great Stuff combo a lot of people use.

EPS styrofoam still surprising to me how much water it absorbs. Reading about it a little, its made from styrofoam beads and while the beads are closed cell and do not absorb much moisture, the spaces between the beads do allow moisture penetration and this may account for the 60+ grams of water absorbed.

I cut each of the samples to see if the inside showed any sign of moisture or of an advancing water front. I did not see any sign of wetness on the sample cross sections except for the plywood. The Great Stuff had large bubbles in the cross sectional cut, but no sign of any moisture getting into them.


Gary
Gary - Thanks Again !!

The results on the EPS does not surprise me at all. We rarely see it specified in areas n buildings where it could get wet.

Polyiso foil faced with exposed edges also not surprise here. RD mentioned he coats the edges on foil faced to resist the water absorption on the edges. Another method would be to use aluminum foil HVAC tape to seal the edges back to the foil face (ie all aluminum cover edges & faces). Of course if the foil faced polyiso is installed in a location like the floor and if the floor peak corrugations stress the thin aluminum foil then the polyiso foam board has raw exposure.

In my mind (environment not considered), there are only two systems I would use in these vans (rigid polyiso & great stuff “xps n the floor with no great stuff”) or (a entire spray foam job). Although I used the first one mentioned, I was on the fence when I insulated & I still am on the fence as to which is better. If & this is a very big IF, the spray foam acts like a water vapour barrier from the metal van skin to the surface of the spray foam and (this is a very big AND) the foam seal against the metal van skin does not separate at all over the years of road travel allowing water vapour get to the metal skin, then I am inclined to think the “Spray Foam Job” is superior to the rigid board insulation as in theory it solves the “air barrier” “dew point” problem which is in my mind the biggest issue to solve in a Van’s Building Envelope Design. That being said, I’m not convince in “real life” the spray foam will function per described (vapour air barrier with no cracks or failed bonds to the metal skin, or an exterior leak thru the metal skin and the freeze thaw action of working the spray metal bond apart).

I do realize I sound like an over concerned science nerd spewing my worries of the “Van Envelope”, and I’m not really a freak, but I do have a keen interest attempting to solve this puzzle. At the end of the day, most DIY just want to pick a system and get it complete. I’m a realist in my perspective of whatever they choose it will probably function ok over the “life of their Vans.
 

·
Registered
Joined
·
1,198 Posts
@RV8R , do you happen to remember the depth of panels on the walls?
Distance from face of the ribs to the exterior skin?
Hey RnR

I got a deal on fiberglass faced 2” polyiso that I used in the walls (there were areas I had to use 1” to get it to fit around the wheelwells). IIRC, where I placed my plywood wall panels the cavity available for insulation thickness is a minimum of 2” and maybe more than 3” in some areas (inside plywood panels are set at a different curve than the metal van skin walls).
 

·
Registered
Joined
·
1,556 Posts
Hi,
I suppose the last thing this forum needs is yet another opinion on insulation, but having spent the last couple of days thinking about insulation, I can't resist. This is mostly from the perspective of moisture control, which effects rust/corrosion and mold.

For the four common schemes in use on vans...

Spray foam polyurethane
This is closed cell polyurethane foam sprayed directly on the van sheet metal.

Followup with Great Stuff to insulate the metal ribs.

How you hope it works:
The spray foam bonds tightly to the sheet metal. Even on a cold day with warm humid air inside the van, there will be no condensation on the van skin because the water vapor cannot penetrate the foam, and if the water vapor cannot get to the sheet metal, there can't be any condensation. You also won't get condensation on the inside surface of the foam either because its warm enough to be above the dew point of the warm humid air inside the van.

Performance -- R6 per inch (very good)
Install labor (DIY) -- a day and a half (with somewhat high stress)
Cost -- $370 ish (walls and ceiling)

Risks:
That the foam may deteriorate over time or separate from the sheet metal, which might allow moisture to get behind the foam or cause squeaks.
That spraying the foam may wrinkle the sheet metal as it cures.
That the areas that are difficult to spray (eg inside ceiling ribs) won't get insulated and therefore will leak heat and condense water.
That you may want to remove the foam someday -- in which case you are in for a lot of scraping.
Having lived with this scheme in my van for the past 5 years I think the risk of any of these things happening is low.

Polyiso rigid foam board -- method 1 (no drainage channels)
Polyiso rigid foam board with aluminium face sheets is adhered to the van sheet metal with a liberal application of Great Stuff Pro urethane foam in a can. Enough Great Stuff is used that there are no open pockets between the Polyiso and the sheet metal, or at most only some small isolated pockets with no air route to them.
The edges of the foam boards are also sealed and insulated with the same Great Stuff foam. The Great stuff can also be used to insulate inside the ribs etc. if you have enough patience.

How you hope it works:
Basically exactly the same as the spray foam methods listed just above. That is, the Polyiso plus Great Stuff leaves no path for air with water vapor to get to the cold sheet metal, so no condensation on the sheet metal, and no condensation on inside of the Polyiso either because its above the dew point.

Performance -- R6 per inch (very good)
Install labor (DIY) -- 2 days?
Cost -- $160 ish (walls and ceiling)

Risks:
That the foam may deteriorate over time or separate from the sheet metal, which might allow moisture to get behind the foam or cause squeaks.
That the areas that are difficult to spray (eg inside ceiling ribs) won't get insulated and therefore will leak heat and condense water.
That you may want to remove the foam someday -- in which case you are in for a lot of scraping.
Following the stories of lots of people on this forum who have used this method and have had good results over time, I think these are low risks.


Polyiso rigid foam board -- method 2 (with drainage channels)
Polyiso rigid foam board with aluminium face sheets is adhered to the van sheet metal with Great Stuff Pro urethane foam in a can. The Great Stuff is used in vertical lines on the back of the Polyiso such that there is enough to adhere it well to the sheet metal, but sparse enough to leave vertical drainage channels between the sheet metal and the Polyiso. This method allows for the possibility that water vapor will get behind the Polyiso in some way and condense -- the drainage channels provide a way for it to drain. Just by their existence, the drainage channels do provide a route for water vapor to get to the sheet metal, but also a way for any condensation to dry out or drain out when conditions change, and the van skin is protected by galvanizing and paint, so some moisture exposure won't hurt it.

The edges of the foam boards are also sealed and insulated with the same Great Stuff foam. The Great stuff can also be used to insulate inside the ribs etc. if you have enough patience.

How you hope it works:
Basically the same as the spray foam methods listed just above. That is, the Polyiso plus Great Stuff leaves no path for air with water vapor to get to the cold sheet metal, so no condensation on the sheet metal, and no condensation on inside of the Polyiso either because its above the dew point.
Additionally, any water vapor that does make its way between the Polyiso and the sheet metal and condense has a way to drain out or dry out.

Performance -- R6 per inch (very good)
Install labor (DIY) -- 2 days?
Cost -- $160 ish (walls and ceiling)

Risks:
That the foam may deteriorate over time or separate from the sheet metal, which might allow moisture to get behind the foam or cause squeaks.
That allowing an air path between the Polyiso and the van sheet metal will result in condensation behind the Polyiso and eventual problems.
That the areas that are difficult to spray (eg inside ceiling ribs) won't get insulated and therefore will leak heat and condense water.
That you may want to remove the foam someday -- in which case you are in for a lot of scraping.
Following the stories of lots of people on this forum who have used this method and have had good results over time, I think these are low risks.


Thinsulate
Thinsulate insulation from 3M is adhered to the van sheet metal with a 3M spray adhesive. Care is taken to make sure there is a path for air to flow through the insulation for keeping it dry.

The metal ribs can be filled with more Thinsulate, or with Great Stuff, or over insulated with an insulating tape.

How you hope it works:
Since the Thinsulate is highly permeable to water vapor, there will be incidences of condensation or ice on the sheet metal and in the outer part of the insulation, but the same high permeability to air flow will result in rapid drying out of the sheet metal and insulation via the ventilation air path through the insulation when conditions are favorable for drying. The van skin is galvanized and painted and will not be adversely affected the the water exposure episodes.

Performance -- R3.3per inch (good)
Install labor (DIY) -- 1 and a half days? and less messy than working with Great Stuff
Cost -- $430 ish (walls and ceiling with 2 inch thick material)

Risks:
That the frequent episodes condensation on the van skin will take their toll over time and result in rust or corrosion or mold.
That the adhesive will fail over time and the Thinsulate will not be well adhered to the sheet metal -- perhaps resulting in settling.
Following the stories of lots of people on this forum who have used this method and have had good results over time, I think these are low risks as long is there is an airflow path for drying out the insulation.

--------
Bottom line is that I think any of these methods is quite likely to result in good thermal insulation that will hold up for the life of the vehicle.

For me, if I were doing it again, I'd go with the Polyiso method with no drainage channels. I'd probably also use two layers of 1 inch insulation where frame depth allowed.

Gary
 

·
Registered
Joined
·
1,812 Posts
Wouldn't it be counter productive to intentionally create a space for air movement and condensation, for the sake of letting the condensation dry out?
Isn't that basically the same as digging a hole to collect water, just so you can install a pump to pump it out?
Why not simply not dig the hole,...or create the space?
And wouldn't allowing air movement, increase the space's thermal conductivity and decrease it's ability to insulate?
I would think that the best thing to do (to ease your mind of any concerns) is to not allow gaps and if there are any, not allow air movement.
 

·
Registered
Joined
·
1,556 Posts
Wouldn't it be counter productive to intentionally create a space for air movement and condensation, for the sake of letting the condensation dry out?
Isn't that basically the same as digging a hole to collect water, just so you can install a pump to pump it out?
Why not simply not dig the hole,...or create the space?
And wouldn't allowing air movement, increase the space's thermal conductivity and decrease it's ability to insulate?
I would think that the best thing to do (to ease your mind of any concerns) is to not allow gaps and if there are any, not allow air movement.
Hi RNR,
Honestly for the two ways of doing Polyiso (with and without provisions for draining the area behind the insulation), I think you can make a pretty good argument for either approach, and I think either approach is likely to give a good long life. If you don't do the drain path, and you do a good job of applying Great stuff to the full back of the panel such that it expands to fill the small gap between the back of panel and sheet metal that its likely that no condensation will happen because there is no path for the water vapor to get to the cold metal. If somehow water vapor does get there, you have the galvanizing and paint to protect the metal. One potential route for water to get there is a leak in a sheet metal joint that allows rain water in.
If you go the other route with drain channels, I don't think that the insulation value will be reduced by much, and the same drainage path that might allow some water vapor to get to the metal also provides a drying path. And you have the galvanization and paint to protect the metal.
I used to be fully in the camp that favored fully sealing the Polyiso to the metal to exclude water vapor, but now I think either approach will work and the thought that made change is that when you think about the van sheet metal, on the outside, we expect it to hold up to 20+ years of rain, snow, sun, grime, mud, etc. -- doesn't it seem like the inside should be able to handle occasional condensation? I'd still do it with the full sealing approach, but seems like either way will work.

For the Thinsulate case where there will be frequent condensation or ice formed on the inside of the sheet metal because the Thinsulate is so permeable to water vapor, I think it makes sense to think about providing for at least some ventilation through the Thinsulate so it can dry out after a condensation event. Again, I think the galvanization and paint counts for a lot.

Just my 2 cents.

Gary
 

·
Registered
Joined
·
3,061 Posts
@GaryBIS
Is there anything to be gained by not having the insulation in direct contact with the metal?

Heat transferring between the metal and insulation vs having a .5" separation between the two.

In my mind this makes sense, I know it's just splitting hairs.
 

·
Registered
Joined
·
1,812 Posts
I think it would be a good thing if the air was trapped and sealed in the space.
Kinda like all the little cavities trapped inside foam insulation.
Air is a lousy conductor of heat. But if the air can move, it will simply carry the heat with it. So it loses its insulating properties.
 

·
Registered
Joined
·
3,061 Posts
Over thinking here.

Scenario, use the recessed section behind the driver's seat, roughly 24" x 24". Imagine putting .5" standoffs on a 1" thick polyiso board and installing it with spray foam along the perimeter.

Summer time
If you have a gap you get a 2 radiant barriers ( metal skin and polyiso shiny side), I understand that 3 radiant barriers is pointless. So if the skin is 120F, the insulation won't be 120F, maybe the air gap delays the insulation from heating up.

Winter time
Not sure if there is anything to be gained by having an air gap, maybe by trapping air in the individual sections of insulation.
 

·
Registered
Joined
·
1,812 Posts
The ugliest but most efficient would be an exterior reflective surface, a thick layer of foam or other material that traps air and then an interior reflective material.
Sandwiching reflective layers anywhere in the middle would be pointless for the purpose of reflection.
 

·
Registered
Joined
·
1,812 Posts
It is splitting hairs and the inside of a van is an imperfect little world. So a lot of this is not life or death.
But I think it's fun to learn and discuss.
My goal is not to attain the perfect utopian max efficiency because it would take an impractical amount of money and work to achieve that.
My goal is to simply avoid doing anything pointless or even destructive. I don't really see too many people doing anything I would consider destructive, but I do see a lot of things that are pointless and waste time, money and material.
 

·
Registered
Joined
·
4,373 Posts
I’m not worried about rust. I’d worry about the potential for dank smell. Since I have such a low tolerance for that dank smell, it’s one reason I chose Thinsulate. I have no idea scientifically whether it matters, but my feeble brain likes that the van breaths. Perceptions, whether valid or not, matter.
 
161 - 180 of 190 Posts
Top