Best Insulation for Walls/Ceiling

Best Insulation for Walls/Ceiling

  • Polyiso, PIR, ISO

    Votes: 14 8.3%
  • XPS (Blue/pink 'Styrofoam')

    Votes: 8 4.7%
  • EPS (White 'Styrofoam')

    Votes: 2 1.2%
  • 3M Thinsulate SM600L (synthetic fiber)

    Votes: 99 58.6%
  • Fiberglass rolls or batts

    Votes: 0 0.0%
  • Polyurethane foam (white/yellow spray)

    Votes: 10 5.9%
  • Icynene foam (eco-friendly spray, closed cell)

    Votes: 3 1.8%
  • Sheep's wool

    Votes: 33 19.5%

  • Total voters
    169

travisap

Member
Trying to make a decision on the type of insulation material for the floor and ceiling.

What do you recommend based upon your own experience or research? Consider these variables when making your in your decision:

1) R Value
2) Installation effort
3) Toxic/safe
4) Cost
5) Thickness

Thanks!!
 

sprinterPaul

Active member
Trying to make a decision on the type of insulation material for the floor and ceiling.



What do you recommend based upon your own experience or research? Consider these variables when making your in your decision:



1) R Value

2) Installation effort

3) Toxic/safe

4) Cost

5) Thickness



Thanks!!


I did thinsulate and polyiso combination. Works fantastic.


Thinsulate for walls and doors.

Polyiso for roof. And then more on top of the thinsulate since even the thickest stuff doesn't fill up walls completely.


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hein

Van Guru
Trying to make a decision on the type of insulation material for the floor and ceiling.

What do you recommend based upon your own experience or research? Consider these variables when making your in your decision:

1) R Value
2) Installation effort
3) Toxic/safe
4) Cost
5) Thickness

Thanks!!
Why not include noise reduction as a criteria and list products like Dynamat, Fatmat, Noico, etc? 3M Thinsulate(TM) also competes with them.
All the best,
Hein
 

Zundfolge

1-2-4-5-3
I'm currently re-doing my van and insulation is at the top of the list. Before I had done enough research I was one of the ones who glued reflectix to the entirety of interior wall surfaces, and then used EPS (whoops) on the ceiling, and fiberglass in the walls (because I had it and it was always meant to be temporary).

I know there are 1000 insulation threads but conventional knowledge takes a while to catch up, so repetition is key. I'm interested to see where this goes. I've been thinking of maybe just buckling down and ordering some Thinsulate (Hein, been meaning to send you a message or call you about that), but I'm rethinking that now after doing a lot of reading and consideration of my finances.

I am narrowing it down to two options that are realistic to my personal current situation, which among other things has to consider materials cost - a factor that makes Thinsulate unrealistic. I think I will be going Polyisocyanurate board (polyiso) in my ceiling, or possibly closed cell spray foam (Foam it Green) as I have a kit from a job that I may have enough left over to use for the van.

Let's get these values here-
R-Value/in:

Spray Foam.....R-6-7
Polyiso............R-6
XPS................R-5
EPS................R-3.9
Fiberglass.......R-3.7
Sheep's Wool..R-3.7
Thinsulate......R-3.2

(Note: If any of my values are off please let me know and I'll correct them, this was based on the info I could find)

We all know and the OP stated that R-Value is not the only consideration, so and taking into account the other factors in my mind this narrows it down to Thinsulate, Polyiso/spray foam kits, and sheep's wool.

I really like sheep's wool for its natural sourcing/non-petroleum based, moisture wicking capabilities, ability to retain 30% of its weight in water, non-sagging, non-toxic etc etc nature and *I think* that from the standpoint of a well rounded product that checks all of the boxes it wins. Affordable, R-value, moisture properties, sustainability, sound deadening, easy install.

I know that so many on here are big fans of Thinsulate, and I know Hein has done his research and preached on here for a long time now, so I would definitely value his opinion regarding everything I'm saying, I'm just trying to trudge through it all and make my own decision too.

That brings me to: why would one choose Thinsulate over Commonly available polyiso board? Not taking cost into consideration, how is Thinsulate better? Polyiso board is almost 2x the r-value, and above all, we want to stay at a comfortable temperature in our vans. If I can insulate the ~1 3/4" in my ceiling with about R-10 using polyiso, can anyone convince me why I'd want to use R-6ish Thinsulate (or any other material?) instead?

Thanks all.
 
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gltrimble

Well-known member
I started out with a plan to use polyiso and as SprinterPaul mentioned it does work in some of the large flat areas. But installing it in the bulk of the van became a chore and a big mess. Trying to cut and fit the polyiso cleanly is difficult involving a lot more labor on my part. I value my time and prefer to dedicate it to more important tasks on the van. My math said the Thinsulate was far less costly when considering material and labor.


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GSWatson

2013 144
I did 1” polyiso glued to the van skin using a Great Stuff pro applicator gun, and then filled in the gaps around the polyiso with the gun. That meant I didn’t have to be exact with the polyiso cuts, and the gun lets me lay down a precise bead, and that becomes my vapor barrier as well. It also stiffens up the van sheet metal.

On the other hand, rigid foam is exactly that - rigid. Which means that it’s not the best at noise reduction; you want a pliant material to absorb the energy of the sound waves. So I put Thinsulate on top of the PI. Overkill perhaps; the PI and gun and GS cost me around $200; the Thinsulate was around $500 if I remember right.

In the next van, I’m doing just Thinsulate. It may seem expensive now, but insulation is the first thing you’re going to do, and the hardest thing to re-do, so I makes sense (and cents) to do it right the first time.

(Also, I’d be worried about the sheep’s wool retaining that moisture as a rust worry).


Greg
 

MotoXPress

Member
Polyiso on the floor or ceiling also reduces the standing height - a big concern for taller people.


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sprinterPaul

Active member
Polyiso on the floor or ceiling also reduces the standing height - a big concern for taller people.


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On the ceiling you have 1.5" of rib height to fill. So you don't really lose anything. The floor is different. But I fail to see how adding Thinsulate under the floor and them compressing it helps. I'm sure the part thats in the corrugations helps. I didn't insulate my floor and it's been fine.


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BHamB

New member
I went with .5" EPS foil board backed with Havelock wool on the ceiling. Havelock wool on the upper and mid walls, easy install, no adheisives required. I put 3M thinsulate on the lower walls; however, I am not a huge fan of the required 3m adhesive. Moisture and condensation seems to naturally work its way down to the weeping holes. I'll check it in 12 months and update accordingly.
 

hein

Van Guru
I went with .5" EPS foil board backed with Havelock wool on the ceiling. Havelock wool on the upper and mid walls, easy install, no adheisives required. I put 3M thinsulate on the lower walls; however, I am not a huge fan of the required 3m adhesive. Moisture and condensation seems to naturally work its way down to the weeping holes. I'll check it in 12 months and update accordingly.
There is a low VOC 3M 90 high temp spray adhesive available and we are working with 3M to determine which PSA (peel and stick) tape will work best especially in cooler temps. Many people tend to use too much spray adhesive. The trick is to place the Thinsulate(TM) SM600L in the wall cavities and then pull back the edges and spray adhesive behind and near the top of the pieces in such a way that it gets on both the Thinsulate(TM) fibers and also the metal skin. Then gently press it back in place.

Sheep's wool does appear to be getting some traction lately so we'll have to see how it holds up down the (bumpy) road so please keep us posted with an update. Denim was popular but it got soggy when condensation got to it over time. Many organic insulation products are sprayed with Borates to achieve the FVMSS-302 flammability rating required in vehicles. When moisture is present this can leach out and form boric acid which is corrosive. Some folks and pets develop a reaction to it. Thinsulate(TM) contains no such additives.

All the best,
Hein
 
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radair603

Member
After using Thinsulate I would not consider anything else. It is SO easy to cut with scissors or a rotomat, can be fished through ribs and tight spaces and is not toxic or itchy. $600 for a roll seems very expensive at first but the time saving makes up for it. It's a drop in the bucket when doing a full build with diesel heater, windows, solar-electric, awning, refrigerator, water system, etc.

Edited to say I also added 1/2" rigid foam and a layer of Reflectix to my ceiling because I have a black van that can heat up like an oven. Great in cold temps but not so great in the hot desert.
 
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hein

Van Guru
Valid point...but in reality of you are in the van still at the point that the fire reaches the insulation, the toxic gasses are likely the least of your problems.
I would hope and pray that you and your precious cargo are safely out of the van and well clear of any smoke. I am also considering the safety of the firefighters, homes nearby, and folks driving by. Sorry to be sort of blunt in this thread. My training and experience as engineer has allowed me to see past what most folks consider as part of a failure analysis.

All the best,
Hein
 
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NNGVan

2008 3500 Custom Uplift
A system is better than any single product.

Given the ribs have 2+ inches on he walls and ceiling is 1.5 here is what I did.

1) Polyiso 1” directly on the skin everywhere I could. Walls and ceiling, etc.
2) Small closed foam spray kit 200 lbf kit everywhere the poly didn’t fit.
3) Attic Foil not reflectix (much cheaper) on the front/back of my ThermalPly which I nailed to the ribs using 1x2 furrings directly on the ribs. This gave me a nice air gap for radiant heat.
4) Large Gap Filler for inside the ribs.
Cost was cheaper than a roll of Thinsulate
System R value 9+ (some argue about the advantage of radiant heat but there’s a 15-20° difference in Mexico in direct sunlight)
It took 4 times as long but I wasn’t in a hurry do it right it’s the hardest thing to do over.
No idea on the toxic levels everything is sealed and on the other side of the wall.

You lose about .5-.75 do to the furrings but man it handles Canada to Mexico better than anything I’ve seen.
 

Robert-NE

New member
NNGVan, how did you come up with a system R value of 9+?

Everyone else, I am seeing a big push for Thinsulate, and I can appreciate some of the benefits over other forms of insulation. However, while still in the planning phase of my build, I am trying to understand the lack of votes for closed-cell spray foam based on the five criteria points:
1) R Value - closed-cell spray foam has the highest R-rating per inch of any other common materials
2) Installation effort - It is messy and requires proper technique required to prevent van wall distortion, but installs quickly compared to cut-and-fit of others.
3) Toxic/safe - I assume this is the number one benefit of Thinsulate over spray foam?
4) Cost - DYI spray foam kits cost about the same as Thinsulate
5) Thickness - Again, spray foam has the highest R-value per inch of any common insulation product

So, is the potential safety factor of spray foam the ONLY downside?
 

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