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will rutledge Posted: Nov 02, 2012 01:11 AM	Open Cell Spray Foam on metal siding I am building a 30x60 metal building in San Antonio Tx. It has red iron main frame with all 2x6 wood framing 16" on center on walls in between I-beams instead of steel purlin. Sides and roof will all be tin sheets. It will be a residential home inside. My plan was to have 5.5", open cell spray foam sprayed directly on the tin sheets. Drywall would then be applied on interior walls. My question is: Are there any issues doing this? Are there any issues with moisture when it comes to spraying foam insulation directly on the tin? Any advise/suggestions would be greatly appreciated.
quentin Posted: Nov 02, 2012 08:42 AM	I never use open cell on metal. The reasons are that metal seams can leak over time, the benefits in the strength added by closed cell quietens the structure tremendously and closed cell glues it all together making it much stringer in a wind storm. While open cell would be cheaper, in the end going with closed cell at 3 inches would provide about the same level of insulation ability but the benefits for very little cost difference is well worth it. Adding in that you plan to live there just makes it even more of a benefit for the costs. Think of it this way, open cell will be quiet in rain and storms but it will still let the metal flex so seams can open up a bit to let wind and moisture in. Closed cell will do a lot to prevent the metal from flexing in the first place. When you tap on it from the outside after using closed cell, it will sound almost like you are hitting plywood. That is how much stiffer and stronger it would all be. Just make sure you have all your windows and doors planned out first. I had a client where we did this on his garage for his business working on cars, semi, farm tractors and etc. After we were done they decided to add another garage door. Yeah, he called me back to tell me how hard it was to do and it had sold him on closed cell for metal buildings for life after! We had a goof laugh on proper planning BEFORE doing that work since it also cost him a few hundred dollars in waster foam and had everyone cussing me out for a week while they cut it all and then tried to pull the foam off to reuse the metal for part of a farm fence.
mason Posted: Nov 02, 2012 01:25 PM	I am with Quentin on this one. I like the ability of the closed cell foam to glue the metal building panels together to minimize structural movement. Check out my article on using SPF for structural enhancement on my website, masonknowles.com
Posted: Nov 02, 2012 05:00 PM	Totally agree with both gentlemen above, I am going to be in San Antonio on Monday through Monday The 5th to the 12th call me if I can be of assistance. Bill
will rutledge Posted: Nov 02, 2012 07:22 PM	Thanks for the info guys. So, would you guys recommend staying away from open cell all together? Is 3" where I should stop due to the law of diminishing returns? Are there any issues at all with applying the SPF directly to the metal and then drywall on the interior wall? Mr. Knowles: Very good write ups on your website. I am learning a lot from them.
mark moyer Posted: Nov 02, 2012 08:14 PM	i would disagree with the gentlemen ...i would have no problem spraying either product to a well built structuture... you could achieve good rvaule for good $$ value... i see no reason for the extra $$ for the value added properties that the wonderful product closed cell foam has to offer in your application as you decribe it,,. it looks like you are looking for an air impermiable insulation of decent rvalue.... open cell could afford you that... typically for less money,,, (we apply both products by the way,, and was weened on closed cell foam by the way.. and prefer to shoot closed cell foam by the way..)
Cory Boehs Posted: Nov 02, 2012 10:46 PM	Amen, Dude! We love spraying closed cell, and 80% of what we do is closed cell, but 3" of CC versus 6" of OC will cost quite a bit more.
will rutledge Posted: Nov 03, 2012 12:12 AM	Aside from structural integrity is concerned, what would be my best choice? The building is over engineered and built far beyond what is required to be a sound structure. Also, here in south/central Texas, on flat land surrounded by trees, severe weather/high winds is not a large issue. Of course, value and saving a dollar is a motivating factor, however I want to do things right the first time around. Are there any issues aside from loss of structural integrity with open cell vs closed cell with my particular application?
mark moyer Posted: Nov 03, 2012 07:57 PM	"what would be my best choice?" closed cell foam,,imho..the more the better.. 4" would tickle me just wunderful.. "I want to do things right the first time" same as above..
mason Posted: Nov 06, 2012 12:24 PM	The main difference in using closed cell and open cell foam is the structural enhancement and water resistance. If the building is strong and not expected to move due to thermal shock or structural movement, and your metal sheets wont move and leak over time, then the open cell can work fine. You would need to spray roughly 1.75 to 2 times the amount to obtain the same R value of the closed cell foam. I like to spray the studs or joists as well. Less thermal bridging and less air infiltration and with the closed cell foam even more structural enhancement

Author

Comments

will rutledge

Posted: Nov 02, 2012 01:11 AM

Open Cell Spray Foam on metal siding

I am building a 30x60 metal building in San Antonio Tx. It has red iron main frame with all 2x6 wood framing 16" on center on walls in between I-beams instead of steel purlin. Sides and roof will all be tin sheets. It will be a residential home inside.
My plan was to have 5.5", open cell spray foam sprayed directly on the tin sheets. Drywall would then be applied on interior walls.
My question is:
Are there any issues doing this? Are there any issues with moisture when it comes to spraying foam insulation directly on the tin? Any advise/suggestions would be greatly appreciated.

quentin

Posted: Nov 02, 2012 08:42 AM

I never use open cell on metal. The reasons are that metal seams can leak over time, the benefits in the strength added by closed cell quietens the structure tremendously and closed cell glues it all together making it much stringer in a wind storm.

While open cell would be cheaper, in the end going with closed cell at 3 inches would provide about the same level of insulation ability but the benefits for very little cost difference is well worth it. Adding in that you plan to live there just makes it even more of a benefit for the costs.

Think of it this way, open cell will be quiet in rain and storms but it will still let the metal flex so seams can open up a bit to let wind and moisture in. Closed cell will do a lot to prevent the metal from flexing in the first place. When you tap on it from the outside after using closed cell, it will sound almost like you are hitting plywood. That is how much stiffer and stronger it would all be.

Just make sure you have all your windows and doors planned out first. I had a client where we did this on his garage for his business working on cars, semi, farm tractors and etc. After we were done they decided to add another garage door. Yeah, he called me back to tell me how hard it was to do and it had sold him on closed cell for metal buildings for life after! We had a goof laugh on proper planning BEFORE doing that work since it also cost him a few hundred dollars in waster foam and had everyone cussing me out for a week while they cut it all and then tried to pull the foam off to reuse the metal for part of a farm fence.

mason

Posted: Nov 02, 2012 01:25 PM

I am with Quentin on this one. I like the ability of the closed cell foam to glue the metal building panels together to minimize structural movement.

Check out my article on using SPF for structural enhancement on my website, masonknowles.com

Posted: Nov 02, 2012 05:00 PM

Totally agree with both gentlemen above, I am going to be in San Antonio on Monday through Monday The 5th to the 12th call me if I can be of assistance.
Bill

will rutledge

Posted: Nov 02, 2012 07:22 PM

Thanks for the info guys. So, would you guys recommend staying away from open cell all together? Is 3" where I should stop due to the law of diminishing returns? Are there any issues at all with applying the SPF directly to the metal and then drywall on the interior wall?

Mr. Knowles:

Very good write ups on your website. I am learning a lot from them.

mark moyer

Posted: Nov 02, 2012 08:14 PM

i would disagree with the gentlemen
...i would have no problem spraying either product to a well built structuture...

you could achieve good rvaule for good $$ value...

i see no reason for the extra $$ for the value added properties that the wonderful product closed cell foam has to offer in your application as you decribe it,,.
it looks like you are looking for an air impermiable insulation of decent rvalue....
open cell could afford you that...
typically for less money,,,

(we apply both products by the way,,
and was weened on closed cell foam by the way..
and prefer to shoot closed cell foam by the way..)

Cory Boehs

Posted: Nov 02, 2012 10:46 PM

Amen, Dude! We love spraying closed cell, and 80% of what we do is closed cell, but 3" of CC versus 6" of OC will cost quite a bit more.

will rutledge

Posted: Nov 03, 2012 12:12 AM

Aside from structural integrity is concerned, what would be my best choice? The building is over engineered and built far beyond what is required to be a sound structure. Also, here in south/central Texas, on flat land surrounded by trees, severe weather/high winds is not a large issue. Of course, value and saving a dollar is a motivating factor, however I want to do things right the first time around. Are there any issues aside from loss of structural integrity with open cell vs closed cell with my particular application?

mark moyer

Posted: Nov 03, 2012 07:57 PM

"what would be my best choice?"
closed cell foam,,imho..the more the better..
4" would tickle me just wunderful..

"I want to do things right the first time"
same as above..

mason

Posted: Nov 06, 2012 12:24 PM

The main difference in using closed cell and open cell foam is the structural enhancement and water resistance. If the building is strong and not expected to move due to thermal shock or structural movement, and your metal sheets wont move and leak over time, then the open cell can work fine. You would need to spray roughly 1.75 to 2 times the amount to obtain the same R value of the closed cell foam. I like to spray the studs or joists as well. Less thermal bridging and less air infiltration and with the closed cell foam even more structural enhancement

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