Great Stuff spray foam insulation?

[debit.servus]

To start off I know it's not the same to polyurethane, but it's waaay cheaper than paying someone to polyurethane a van. Has anybody used DOW GREAT STUFF spray foam insulation in a mobile dwelling, and how has it held up over the long term?

 

[SoulRaven]

If you've ever removed spray foam from a van, the rust and mold behind it is not a pretty sight.

 

[GrantRobertson]

The folks over at Skoolie.net vehemently recommend against it. Great Stuff is open cell foam, so moisture and humidity can penetrate it. That humidity can then condense against the cold metal body, thus promoting rust.

 

[BradKW]

There is a relatively new product call Gaco Flash Foam that might prove very useful. Gaco is a well known roof coating company, odds are there's a distributer near you...here its sold through Ace Hardware.



It is a closed cell 3# foam that comes in kits. Its 2 part, so you get 2 propane size containers, and the gun + hose to hook them up. I believe we paid under $300.

I contacted their area rep via email to ask about R-value and appropriateness for RV/marine use as insulation. He responded, saying: " I do not see why this wouldn’t work. The foam kits have an R-value of 7 for every inch. I used it on my A/C duct work inside my garage and attic."

copied from another post, pic of Great Stuff removed...shows how it trapped moisture:

http://i557.photobucket.com/albums/ss15/wrcsixeight/036copy_zps57f419e1.jpg

 

[Almost There]

To start off I know it's not the same to polyurethane, but it's waaay cheaper than paying someone to polyurethane a van. Has anybody used DOW GREAT STUFF spray foam insulation in a mobile dwelling, and how has it held up over the long term?

Do yourself a favor and don't use it!

Aside from the fact that it's open cell foam so that it attracts and holds moisture, it's been known to deform the outer skin on vehicles. If you spray it in the upright posts in a van, the post metal is stronger than the wall metal so the expansion pressure is on the outer panel. Also, if it's contained in the uprights, it might not even all cure, the center will stay in the original state of wet foam.

Oh and then, given time and vibration from driving, the foam will crumble because it's not actually adhered to the painted metal, so then you get squeaking as you drive.

We tried using it in vans back in the 70s and 80s.

Insulating a moving vehicle is a whole lot more than just blocking out heat...we have movement, structural forces, rust, off-gassing and moisture to all take in to consideration.

 

[highdesertranger]

do not use Great Stuff, it's open cell foam and acts like a sponge. I have seen a couple of people use this and it seriously rotted their sheet metal. highdesertranger

 

[debit.servus]

Wow! I was almost going to pick up a can and decided to practice spending procrastination on buying GREAT STUFF. Then not seeing a thread here I though to ask about it.

I have read the skoolie forum (desire my next rig to be a school bus conversion) and was aware of the corrosiveness of spray foam.

Insulating is just like painting. I haven't seen a decent and cheap method. It's either cheap and short-lasting or super-expensive and long lasting. Somebody should make comformable foam block insulation. Some kind of insulating sheet that one can heat it up, form & stretch it and it will keep it's shape forever when it's cooled back down. Or closed cell spray foam in a can.

 

[LeeRevell]

That Gaco 3lb. foam looks like a pretty good product, though not cheap.  Once applied, consider it permanent.  I wouldn't put it over any electrical wiring or plumbing.

 

[GrantRobertson]

Somebody should make comformable foam block insulation. Some kind of insulating sheet that one can heat it up, form & stretch it and it will keep it's shape forever when it's cooled back down.

Now there's an idea. One could experiment by putting various existing rigid sheet foam products in a low-temp oven and see what happens. Perhaps even devise a temporary solar or wood-fired oven to heat large sheets.

There are also several soft, flexible closed-cell foam products. It is expensive, when purchases brand new, but could be cheap if you buy used matts from various sources.

 

[debit.servus]

"Now there's an idea. One could experiment by putting various existing rigid sheet foam products in a low-temp oven and see what happens. Perhaps even devise a temporary solar or wood-fired oven to heat large sheets."

If I had money for experimenting I would be the tester. So I have a valid excuse, can somebody else conduct rigid sheet foam soften-and-conform testing, documenting AND sharing the process and results???

 

[GrantRobertson]

, can somebody else conduct rigid sheet foam soften-and-conform testing, documenting AND sharing the process and results???

One day. I got other priorities right now.

 

[compassrose]

Just putting this out there to give you ideas, not telling you what you should do (please see disclaimer see the disclaimer about boondocking & vandwellers in my sig)


You can buy the closed cell spray foam and foam it yourself. (please see disclaimer see the disclaimer about boondocking & vandwellers in my sig)

Once upon a time, BM (Before Me) my husband, lived on a house boat. Had to make repairs in the hull. He said he used a pour in closed cell foam. You can still buy this stuff. Problem is that it is a pour in from the top thing or you make a mold. But you may be able to do that (mold aspect) or not. http://www.amazon.com/Pourable-Flot...sr=8-8&keywords=closed+cell+spray+foam(please see disclaimer see the disclaimer about boondocking & vandwellers in my sig)


The CHEAPEST foam insulation would be to use cut-to-fit foam sheathing, a can of Great Foam to fill in the small gaps between the sheets, then put a removable metal skin (roofing metal?) over the whole mess. At some point it will need to be removed for repairs or upgrades. (please see the disclaimer about boondocking & vandwellers in my sig).

This is what I would do for floors (installed from the inside)... the most R per inch would probably be the "closed cell polyethylene" (sleeping bag pad foam). Run 1/2" furring strips between the 1/2" foam pad and deck over it. I have the cheap 1/2" thick sleeping bag pad (light blue now $8 at the not so nearby Wal-Mart) on my floors as rugs. I think I need to buy one or two more. Putting one in the walkway on each side of the bed would be nice for the winter. They are nice and cushy so the rather bony greyhound can lay on the floor and they keep the cold out as well. When it is below freezing outside, I can still walk around barefoot. The convoluted sleeping bag pads are softer underfoot but the goats heads work themselves down into the foam too much. My daughter found large sheets of the stuff but I have not priced it or the shipping out. For convenience, the stuff from Wal-Mart would probably work out better since you could just buy enough to cover the space a 4X8 sheet of plywood fits at a time. If you already covered your floor with plywood you could just layer over the top of it. Use construction adhesive and short screws to hold the furring strips to the bottom plywood until the adhesive dried. Even if you have a finished floor, just run the sleeping bag pads as rugs (or under rugs, I cut mine with kitchen shears). That is if you were inclined to do so. When they get too nasty, I will toss them. I clean mine off with a damp cloth or a damp mop. They do not absorb water. When things warm up and I leave here, I will clean both sides (mop with 1/2 vinegar-1/2 water- few drops of dish soap), let dry, pick them up off the floor and store them in the space behind the daybed or under the air mattress I sleep on until I need them again. (again, see the disclaimer about boondocking & vandwellers in my sig)

Before you complain that this would not be suitable for Vandwellers and/or Boondockers because I do this (sleeping bag pads) in my bus, please read the disclaimer in my sig.

 

[GotSmart]

Just putting this out there to give you ideas, not telling you what you should do (please see disclaimer see the disclaimer about boondocking & vandwellers in my sig)
 please read the disclaimer in my sig.

So Rosey, when do you get your law degree?  

Great suggestions, and a couple of them gave me ideas.  I promise I will not hold you liable if they do not work out perfectly.  

I always enjoy your posts, as there are a lot of nuggets in them.  (No disclaimer, just a warning in my Sig.

 

[compassrose]

So Rosey, when do you get your law degree?  

I'm just tired of some vandwellers and/or boondockers getting all pissy because I tell them what I or someone I knew did to solve a similar problem and it just happens that, as a direct application with no modification, it would not work for a van or someone who boondocks. Of course they have not had to modify anything to work with their vehicle or life style. Hence the "disclaimer" but many forget to see it on the bottom of the post. So I decided it just needed to be pointed out. Perhaps I should point it out BEFORE I post a "what I did in a similar situation" comment.

 

[GotSmart]

I'm just tired of some vandwellers and/or boondockers getting all pissy because I tell them what I or someone I knew did to solve a similar problem and it just happens that, as a direct application with no modification, it would not work for a van or someone who boondocks. Of course they have not had to modify anything to work with their vehicle or life style. Hence the "disclaimer" but many forget to see it on the bottom of the post. So I decided it just needed to be pointed out. Perhaps I should point it out BEFORE I post a "what I did in a similar situation" comment.

:huh:  

But everything you see on the internet works for everyone!     EVERYTIME!   :angel:

A lot of people tried to make grilled cheese sandwiches in their toaster because they saw it done on line.  They are now posting pictures of flaming toasters.   :dodgy:



Common sense seems to not be a thing anymore.   

http://www.cnn.com/videos/us/2015/11/23/grilled-cheese-in-a-toaster-fire-moos-pkg.cnn

 

[compassrose]

They are now posting pictures of flaming toasters.

I prefer flaming bagpipes.  Let's face it, a man in a kilt playing bagpipes and... flames. How hot is that!

[video=youtube]

 

[highdesertranger]

you could use close cell foam. the make kits, it is actually a very good way to insulate. when you do this you must consider it permanent, because it's next to impossible to remove. a little trick you can line whatever you insulate with plastic. in a cavity you can use a trash bag, this keeps the foam from sticking to whatever you are insulating you lose the structural strength you would have gained but believe me it makes it a lot easier to remove. highdesertranger

 

[WriterMs]

Let's face it, a man in a kilt playing bagpipes and... flames. How hot is that!

Obviously he's capable of giving quite a jolt to his sporran, too, about halfway through the performance.

 

[GaryGary]

To start off I know it's not the same to polyurethane, but it's waaay cheaper than paying someone to polyurethane a van. Has anybody used DOW GREAT STUFF spray foam insulation in a mobile dwelling, and how has it held up over the long term?

Hi,

I'm a little surprised to hear all the not so good reactions to Great Stuff -- I use it a lot.

Its made by Dow, and according them it is polyurethane and its also closed cell:
http://dow-styrofoam.custhelp.com/app/answers/detail/a_id/4585/related/1
and
http://greatstuff.dow.com/products/gaps-and-cracks/

I like the Great Stuff pro better in that you use it with a much easier to use applicator. 
I've had good service out of it both inside and outside for many years.  Its also a good adhesive, but if you get it on your skin you will be wearing it for a week.

But, if you plan to insulate your whole van with it, its probably not the best way to go -- it would take a jillion cans.

On my van I bought one of large, two bottle polyurethane kits at Home Depot and sprayed the whole inside of the van with it.  The two bottles are resin and catalyst and when they mix in the disposable nozzle, they start to expand and cure right away.
This is a substitute for having it professionally done and (I think) is quite a bit cheaper -- about $300 on my ProMaster van size.

These are a bunch of pictures from spraying my van:
http://www.buildagreenrv.com/our-conversion/our-conversion-insulation/
This was the first time I ever did this, and it went OK -- its kind of a high stress job in that there are things that can go wrong and you don't have a whole lot of time to recover, but if you read up on it and get fully ready before you start it goes ok.

Since I did my van, I've read about other people converting vans using a different method that I like and would have used if I'd known the whole story.

They take rigid sheets of 1 inch thicky polyisocyanurate foam insulation.  and cut them to fit the larger open spaces of the van walls.  Then spray the back side of the polyiso sheet with Great Stuff pro and place it against the wall.  Then prop it in place with springy strips of wood until the Great Stuff cures.  The areas between the rigid foam sheets are then sprayed with great stuff pro from the regular cans. 
This makes for a good efficient insulation job that is impermeable to water vapor (so no condensation on the van skin), is an efficient insulator (R6.5 per inch), and will stay in place and won't squeak.
This page has an example of the method being used -- its down the page a ways under "rigid foam panel insulatin":
http://www.buildagreenrv.com/design-and-build-information-for-camper-vans/install-insulation/

The polyisocyanurate insulation is available at some Lowes and some Home Depots and some localy lumber yards.  Sometimes they won't know it by that name, but if you look on each sheet it will say polyisocyanurate.  Polyiso also has a high service temperature and will hold up to the hot metal van skin on a hot sunny day, whereas the polystyrene (pink and blue) rigid foam sheets are marginal for this.

Just my 2 cents : -- hope it helps a bit.

Gary

 

[debit.servus]

Is the GREAT STUFF Pro reccommended for long-term van insulation? It has to be better than the regular GREAT STUFF. They should make a polyurethane like two-part insulation in the size of two GREAT STUFF cans. For those who have small spaces to insulate.

As for how much of the van will be insulated, There are a few spots less than 25 sq. ft.