Spray Foam Luck

o1marc

Senior Member
Joined
Dec 23, 2017
Posts
10,479
Location
Dawsonville, Ga.
So I'm at the gym today and run into the brother of a kid that used to work for me when I was doing construction. After the kid left me, he opened his own waterproofing business. I thought of him when I saw his brother and asked if he did spray foam insulation. He says "No, but I do". Sweet, what would you charge me to spray my bus. He says" We bought it to do a couple jobs and it paid for itself already, so it just sits on the trailer at the shop. You want your bus sprayed, come and get it and do it yourself. Well that just made a spray foam job fit in my budget. I think I'll have access to a possible purchase of the equipment and be able to offer it to other skoolies for less.

Day ended well after a poor start. I had nothing planned today so i said F**K It and jumped in the truck to drive 20 miles to the DDS to take my airbrake endorsement test. Called ahead and was told no appointment necessary, it's a walk in test, can be taken up until 1/2 hour before closing. So I drive down there to find the parking lot empty. While she told me the hours of operation, she failed to tell me they are closed on Mondays. I hate wasting 40 miles. I took a 100 question test on line and passed easily. The real test is only 25 question. I'll try again tomorrow.
 
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Hmmmm... i may take you up on the Spray foam, you are not too far away. Skoolie.net discount!
 
So I figure before I mess up my bus I should go see tis type operation in action. I Google for a local contractor and find none I'd get up early enough to drive to. Then I thought, wait a minute, YouTube, yep there it is. I didn't realize it expanded so much, so fast. I need to see where my buddy was getting his materials and compare prices. The cheapest DIY kit I've found covered 1350bf for around $800. I figure my bus is close to 18' floor to floor, and at least 35', or 664sf. Need 2 coats to get 2" everywhere, so it looks like some spaces will get rigid board.
 
Thats my plan as well. I'm going to do the initial coat and see what I have left of the spray foam. I'll do a second pass and anywhere that doesn't get a second coat will get foam board.
 
Thats my plan as well. I'm going to do the initial coat and see what I have left of the spray foam. I'll do a second pass and anywhere that doesn't get a second coat will get foam board.

Advantage to multiple 1" coats is that each coat cures before the second, adding a double vapor barrier. Also by the time I'm ready for the second coat I should have a feel for the gun and accurately finish the job without too much shaving afterwards. I think I will take the time to mask all the ribs to aide in cleanup.
The foam comes in 2 steel canisters, I don't think there's a way to know how much you have left.
 
Need 2 coats to get 2" everywhere, so it looks like some spaces will get rigid board.
You sure about that? I don't know squat about spray foaming but I don't think I've ever seen anyone doing two coats. I think Dzlfreek only did one coat but I think he also only did 1 1/2" as well.


dzlfreek
 
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You sure about that? I don't know squat about spray foaming but I don't think I've ever seen anyone doing two coats. I think Dzlfreek only did one coat but I think he also only did 1 1/2" as well.


dzlfreek

Doing some research showed that by doing mulitple coats with a cure time between each coat gives you a second vapor barrier. A kit will only cover the space with one inch, thus the second kit or coat to get the desired thickness.
 
Doing some research showed that by doing mulitple coats with a cure time between each coat gives you a second vapor barrier. A kit will only cover the space with one inch, thus the second kit or coat to get the desired thickness.
Interesting. The other option tho would be to spray half the bus, switch canisters and then the other half.


Wish I had a number for Dzlfreek. He worked in the construction industry and was quoting spray foam all the time. See what his thoughts are on 2 layers. If I recall correctly, he did say +2" was overkill. I was originally thinking of doing 3 1/2" just because it's a standard 2x4 for framing.
 
Interesting. The other option tho would be to spray half the bus, switch canisters and then the other half.


Wish I had a number for Dzlfreek. He worked in the construction industry and was quoting spray foam all the time. See what his thoughts are on 2 layers. If I recall correctly, he did say +2" was overkill. I was originally thinking of doing 3 1/2" just because it's a standard 2x4 for framing.

I liked the idea of the second skin vapor barrier, thus the 2 coats being better.
 
I liked the idea of the second skin vapor barrier, thus the 2 coats being better.
If it's true then I'm all for it. But color me skeptical. If it's true then why isn't everything 2 or 3 coats?
 
Just want to chime in, having paid for a professional to do my spray foam, I'd do it myself it I could go back. Nobody does as good of a job as you would. I'm having to fill too many shallow areas with great stuff..
 
If it's true then I'm all for it. But color me skeptical. If it's true then why isn't everything 2 or 3 coats?

For the same reason people do things differently. Many i'm sure are not educated and think just spraying it up there is the trick. I seen too often people go to work for a company and learn just enough to go out on their own and yet they are really not educated on all the ins and outs. I'm sure many times the installer wants to get the stuff on and get out and paid. 2 coats is more time and money and they probably don't know the benefit of multi coats. It's seems to me like painting. you get a much better result from multiple thin coats than one thick coat.
 
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You don't want to put it on in coats thicker than around 1-3/4". The foam expands about 25%. I'm told for 2" you can go in one 1-1/2" coat, or 2 thin coats. Anything thicker needs to be done in multiple coats.
 

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