Author Topic: spray foam insulation +/-  (Read 5303 times)

Offline 77FlxTransit

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spray foam insulation +/-
« on: April 23, 2006, 07:05:48 PM »
Heard some pros and cons of spray foam insulation.  I want quality insulation, but I don't want to risk putting waves along my flutted exterior.  Is this really a concern??  Can't afford to risk the whole project.  What are alternatives to spray foam?  Thanks.
Stephen Bahen
Hampton, VA
77 Flx Transit New Look
8v71N, V-730, 40'X96"

Offline Ednj

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Re: spray foam insulation +/-
« Reply #1 on: April 23, 2006, 07:17:59 PM »
I did the spray foam myself with kits from McMaster-carr, I chose this way so I could insulate as I was doing the metal work, without it being completed.
Now keep in mind that these kits are not hot foam, although it does get hot when you do it.
I have such good insulation in my bus that it is almost sound proof, 1 A/C can cool it on a hot day,
If I drove off the road into the water it would probably float, but it “DID warp the metal exterior.
And with a new shiny paint job it does show up.
Sussex county, Delaware.
See my picture's at=
That's Not Oil Dripping under my Bus, It's Sweat from all that Horsepower.
----- This space for rent. -----

Offline dug

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Re: spray foam insulation +/-
« Reply #2 on: April 24, 2006, 03:04:28 AM »
I used 2 layers of .75 RMAX rigid board from Home Depot.  After cutting all those pieces, I can't help but think it would have been faster to spray foam.  I am happy with the result, tho.

75 MC8
Arcadia, FL

Offline Geoff

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Re: spray foam insulation +/-
« Reply #3 on: April 24, 2006, 04:27:16 AM »
Cut foam panels give you more control over what you are doing, and allows you to go back and remove insulation to change something in the future.  Spray foam is way too permanent for me.
'82 RTS AZ

Offline Hobe

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Re: spray foam insulation +/-
« Reply #4 on: April 24, 2006, 05:09:34 AM »
Spray foam comes in different ways. Cold foam comes in two part cold that will not hurt your sides as it softer. And has a low R value, About R 4 per inch. The high dense foam that is put on with heated hose and heated as it comes out of the gun will bend your sides, If not properly supported. The way to stop it is to spray water on the out sides as it is put on. This makes it cool on the skin and do it push toward the insides. My own coach that we travel in, I did not no this because it was the first time that I used high dense foam and my sides are buldged. So if you are using the type that comes in two cans that look like big propain tanks you won't have any problems.  Fred North Florida Bus Conversion

Offline Ericbsc

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Re: spray foam insulation +/-
« Reply #5 on: April 24, 2006, 06:01:36 AM »
I had my Eagle sprayed about a month ago. Made it solid as a rock. Made the upper siding look like crap. I heated and streached it when it was installed. I don't think you would have that problem with the fluted sding as that is the reason it was fluted anyway. I think if the guys had skimmed mine first it would not have buckled. I also thought about spraying cold water on the exterior as the inside was sprayed. I would say if done right, it is by far the best method.

Offline FloridaCliff

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Re: spray foam insulation +/-
« Reply #6 on: April 26, 2006, 05:27:12 PM »
I also used the Rmax boards.

My reasons were that I was doing it as I built and didn''t want to have to prep the coach all at once.

I went one layer glued to the sides between the ribs and a second layer between the firring on the side.

on the roof I have three layers, glued to the outside, above the firring, between the firring.

Very quiet and mucho cheaper than foam.
1975 GMC  P8M4905A-1160    North Central Florida

"There are basically two types of people. People who accomplish things, and people who claim to have accomplished things. The first group is less crowded."
Mark Twain

Offline Kristinsgrandpa

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Re: spray foam insulation +/-
« Reply #7 on: April 26, 2006, 05:58:51 PM »
2" of R-Max polyisocyanurate on both walls and the ceiling for about $550. Got it at Lowes. The guy that works in that dept marked it down since it was a special order.

Was $22.95 I got it for $17.50 per sheet for 1".  They had a minimum on a special order but my order was more.

location: South central Ohio

I'm very conservative, " I started life with nothing and still have most of it left".

Offline NJT5047

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Re: spray foam insulation +/-
« Reply #8 on: April 26, 2006, 07:44:07 PM »
I used two  3/4"  Foamular  panels for a total of 1.5"  in all of the ceiling and skinned window areas.  Foamular came from  Lowes.  Also used in sidewalls.  I don't know how the Foamular compares with the other panels mentioned, but the bus doesn't squeek, and it cools readily. One AC will keep the front cool in any sort of weather.    Bedroom will get a little warm if rear AC is off when the sun is on the coach and it's 100* outside, but once the sun sets, the rear even stays quite cool on just the front AC.   The bedroom has its own AC anyway. 
Found the 3/4" panels easier to form around the roof curves.  The 1.5" panels would work in flat room areas. 
This stuff is a good bit of work to install nicely, but it won't  buck the sides of your bus.  And, there's no major "shaving" or cleanup once its in.
A word of caution...if you use an adhesive to hold the panels, be sure that it is compatable with your foam panel material.   I used both "Great Stuff" (Great Stuff WILL bow any panel... and fiberglass shower stalls  >:() and sealer to seal around some of the edges so the foam wouldn't rub and squeek when driving. 
I believe the panels ended up burning thru about $600 was a noticeable amount.  Worth it for the quietness, and comfort.
Cheers, JR
JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

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