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Author	Comments
Posted: Jan 17, 2007 10:05 PM	Closed Cell depths Is it ok to spray as little as 1/2 inch of closed cell on a metal building to reduce condensation or is 1 inch the minimum recommended?
SprayFoamSupply.com Posted: Jan 18, 2007 07:35 AM	You need 2" to have a vapor retarder. George
Gerry Wagoner Posted: Jan 18, 2007 09:28 AM	1" on the interior of a steel structure will eliminate condensation. Been doing it for 24-years. .5" is too little. have fun, olger
Posted: Jan 20, 2007 09:17 PM	I agree with Olger 1" is all that is needed to prevent condensation. We also have been spraying for over 30 yrs. We have yet to have any problems with 1" applications on metal buildings. 1/2" will stop a lot of the condensation issue however if the temperature differential gets too great condensation can occur on the surface of the foam. The main purpose of the foam is that it keeps the substrate temp closer to the interior ambient temperature. Therefore the temperature diff that causes the condensation happens at a much colder temp then the untreated metal. we have sprayed .5" applications with no problems. You just need to know the customers target inside temp, the average exterior temp, and the interior moisture drive(heat source,slab,moisture produced inside.)Just remember that going with less then an 1" can cause blisters if you don't carefully access the building prior to application. A knowlegable applicator is a successful applicator.
Posted: Jan 22, 2007 08:08 AM	"Just remember that going with less then an 1" can cause blisters if you don't carefully access the building prior to application." please elaborate...blisters due to application error,,substrate moisture,,,ect,, et al..??? to you have an algorythym you follow to "access"??what is your criteria? 'perciate your input and experience!!!
Gerry Wagoner Posted: Jan 22, 2007 08:46 AM	Oh... and don't spray over galvanized. (unless you clean it first).
Posted: Jan 23, 2007 09:52 AM	When spraying a skim coat of spf to a pole building.We want to be sure that the moisture drive and temp differentials are not to much.2lb foam has a nice built in vapor retarder.The thicker the application the lower the perm rating.This is an advantage because it allows a greater vapor transmission rates at thinner applications.Allowing the moisture drive easier travel through.This is a disadvantage if your temp rates between interior and ambient are too great. You will be trying to overwork the foam. Blistering happens on corrugated steel when the moisture in the foam and substrate try to exit too quickly.A little sun the tin heats it up real quick and the moisture cannot exit safely causing blisters. The same happens on flat spf roofs.Prior accessment is key to a successful application.
Jeremy Himmel Posted: Jan 25, 2007 08:26 PM	1" works great for stopping condensation on metal structures. 2" is overkill and rarely will you sell it simply for condensation. If it is to be heated/cooled 2" would be a better option.
Glenn Gamblin Posted: Jan 28, 2007 08:08 PM	How about we all quit selling it by the inch and start selling it by the foot. If we all sprayed foam on at least 1 foot thick, we would then no longer argue about condensation.
Jeremy Himmel Posted: Jan 30, 2007 08:57 PM	Ha yes very nice point, but there simply is an enormous difference in price when you are in a competitive market and have 3 other bids to beat with either your price or your professionalism.

Author

Comments

Posted: Jan 17, 2007 10:05 PM

Closed Cell depths

Is it ok to spray as little as 1/2 inch of closed cell on a metal building to reduce condensation or is 1 inch the minimum recommended?

SprayFoamSupply.com

Posted: Jan 18, 2007 07:35 AM

You need 2" to have a vapor retarder.

George

Gerry Wagoner

Posted: Jan 18, 2007 09:28 AM

1" on the interior of a steel structure will eliminate condensation. Been doing it for 24-years.

.5" is too little.

have fun,

olger

Posted: Jan 20, 2007 09:17 PM

I agree with Olger 1" is all that is needed to prevent condensation. We also have been spraying for over 30 yrs. We have yet to have any problems with 1" applications on metal buildings. 1/2" will stop a lot of the condensation issue however if the temperature differential gets too great condensation can occur on the surface of the foam. The main purpose of the foam is that it keeps the substrate temp closer to the interior ambient temperature. Therefore the temperature diff that causes the condensation happens at a much colder temp then the untreated metal. we have sprayed .5" applications with no problems. You just need to know the customers target inside temp, the average exterior temp, and the interior moisture drive(heat source,slab,moisture produced inside.)Just remember that going with less then an 1" can cause blisters if you don't carefully access the building prior to application. A knowlegable applicator is a successful applicator.

Posted: Jan 22, 2007 08:08 AM

"Just remember that going with less then an 1" can cause blisters if you don't carefully access the building prior to application."

please elaborate...blisters due to application error,,substrate moisture,,,ect,, et al..???

to you have an algorythym you follow to "access"??what is your criteria?

'perciate your input and experience!!!

Gerry Wagoner

Posted: Jan 22, 2007 08:46 AM

Oh... and don't spray over galvanized. (unless you clean it first).

Posted: Jan 23, 2007 09:52 AM

When spraying a skim coat of spf to a pole building.We want to be sure that the moisture drive and temp differentials are not to much.2lb foam has a nice built in vapor retarder.The thicker the application the lower the perm rating.This is an advantage because it allows a greater vapor transmission rates at thinner applications.Allowing the moisture drive easier travel through.This is a disadvantage if your temp rates between interior and ambient are too great. You will be trying to overwork the foam. Blistering happens on corrugated steel when the moisture in the foam and substrate try to exit too quickly.A little sun the tin heats it up real quick and the moisture cannot exit safely causing blisters. The same happens on flat spf roofs.Prior accessment is key to a successful application.

Jeremy Himmel

Posted: Jan 25, 2007 08:26 PM

1" works great for stopping condensation on metal structures. 2" is overkill and rarely will you sell it simply for condensation. If it is to be heated/cooled 2" would be a better option.

Glenn Gamblin

Posted: Jan 28, 2007 08:08 PM

How about we all quit selling it by the inch and start selling it by the foot. If we all sprayed foam on at least 1 foot thick, we would then no longer argue about condensation.

Jeremy Himmel

Posted: Jan 30, 2007 08:57 PM

Ha yes very nice point, but there simply is an enormous difference in price when you are in a competitive market and have 3 other bids to beat with either your price or your professionalism.

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