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Justin Marcinkowski
Posted: Dec 04, 2007 12:19 PM
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Closed Cell Thickness
First I want to thank you for taking the time to read this and respond to my question. Now on to the question. I was curious what the optimal thickness would be for my closed cell spray foam application. The contractor quoted me 2 inches in the walls and 2.5 inches in my vaulted ceiling. I asked about using more and he said it would be overkill. I would tend to believe him since he has money to loose by telling me this. But, I still would like to know if adding more foam, especially to the ceiling, would be worth while. I live near Atlantic City, NJ about 5 miles from the coast. Also, he quoted me for 2.5 inches in my floor which resides over a vented crawl space. I am going to use radiant heat on the floor, so I am again wondering if adding more insulation under the floor would be worth while. Again, thanks for reading this. |
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Gerry Wagoner
Posted: Dec 04, 2007 10:04 PM
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Hello friend. Without disparaging the contractor in the least, I would shift the 2.5" over to the studwalls and bump the vaulted ceiling up to 4". The Department of Energy and your local utility standard would agree. Hope that helps, |
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Posted: Dec 09, 2007 03:37 AM
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what olger said!! foam foams a marvelous air barrier in its first inch of applicaition. it is this air barrier that along with its side to side seamless monolithic application that gives foam its performance "boost". physics is physics,,,, the spfa has a tech doc that shows a 4" app of CC in a cathedralized ceiling has the performance value equal to 14" loose fill fiber or cell....so i too use the 4" app for most of my presentations/suggestions. i have many folks who will upgrade to 6-7" to the lid with proper education(i do a lot of upper end customs) and this is what i would do in my own home if i was spraying it today with 3-4" in the 2x6 sidewall... now if i have a truss with 12" or deeper depth i would consider a open cell application (i like the 12 -15" app for r49 energy star) as long as i can obtain a design spec rvalue since this would be a more affordable application. the 2.5" in the sides would be adequate the 2.5" in the ceiling is half of what you need hope this helps |
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David Lenaker
Posted: Dec 12, 2007 05:41 PM
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do not use open cell in ceiling applications. |
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Rob Granger
Posted: Dec 12, 2007 07:15 PM
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I live in Western NY and I reccomnd to my prospectives 3" in the side wall and 4 inches on the roof deck. The new ICC codes sets minimum R-Values for materials including foam to create a un-vented attic. As far as radiant heat - are you going to put the radiant heat under the floor in the crawl space or on top of the existing floor? If you're putting it under you MUST have an air space between the floor heat tubes and the insulation or it will not work. You need at least an 1 1/2 " - 2" air space then spray your closed cell to some installed cardboard or similar material. |
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Posted: Dec 12, 2007 09:24 PM
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all seasons,,,no open cell in ceilings...ever??why not??? inquireing minds need to know.... |
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Posted: Dec 12, 2007 09:27 PM
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the heating dudes uses thermopan to created the air plenum for the radiant tubeing... the foamdude seals this with 3" or so open cell... it is less expensive than cc,,,easier to remove in the subfloor (which is a greater possibility than in the sidewalls down the road) if needed,,,the customer likes the look of "more insulation" for the $$ they are going to spend (yes its wrong,,the CC is much better thermally but this is the cold hard truth,,,kill me,,,please) enjoy |
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Tim O'Keefe
Posted: Dec 12, 2007 09:28 PM
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We put 1/2" foil faced poly iso board 1 1/2" below the substrate when there is radiant heat below the floor. Then spray 3" of closed cell on top of that in a crawlspace. The 1 1/2" is necessary to allow the whole width of the cavity to be warmed. Otherwise you would only warm the 3/4" area that the PEX tubing touches (not real effective). Tim Granite State Spray Foam Co. |
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Tim O'Keefe
Posted: Dec 12, 2007 09:31 PM
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No open in the ceiling or the roof? We prefer closed cell over open cell, but open cell certainly has its place. It is more cost effective and definitely a better choice that fiberglass batts! Tim Granite State Spray Foam Co. |
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Gerry Wagoner
Posted: Dec 12, 2007 09:49 PM
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Yes. All Season's statement seems too broad to me. oG |
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Justin Marcinkowski
Posted: Dec 13, 2007 08:31 AM
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Sorry for my absenteeism, but I have been following the thread. To answer a few questions. My radiant heat will be going above the subfloor and covered with light weight concrete/gypsum material. I also figured the amount of foam that my contractor wanted to use was a little low. For the record, he quoted me $4500 for the following. Its a 550 square foot room. 13 feet vaulted ceiling. One 13 feet high 14 feet wide 6 feet deep gable rood also vaulted. One 8 feet wide 13 feet high gabled roof. Under the entire 550 square feet floor. It is a fairly complicated room, but there are also a million windows. Now, I don't mind paying for good work, but $4500 seems high for 2.5" in the ceiling and 2" in the walls and 2.5" in the floor. i can't imagine how much $$ he would want to spray 3" in the walls and 4" in the ceiling and god knows how much in the floor. |
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Luke Kujacznski
Posted: Dec 13, 2007 08:48 AM
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check the 2006 icc code, it states that if insulation is to be applied to the underside of the roof deck it must be air-impermiable. also if you live in a colder climate, bsc does not recomend soft foam in the roof |
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D. Backes
Posted: Dec 13, 2007 09:45 AM
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Since when is open cell foam air permeable? Especially when installed in thicknesses of 6" or more (typically) in a roof situation. |
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Tim O'Keefe
Posted: Dec 13, 2007 10:25 AM
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If it must be air permeable doesn't that defeat the purpose of using foam? That does not make sense! Tim Granite State Spray Foam Co. |
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Luke Kujacznski
Posted: Dec 14, 2007 07:11 AM
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is soft foam a certified air barrier? From what i can find it isn't and I think that is what they are getting at in that code. Also didn't the sprayfoam magizine do an article on this a couple months ago and said soft foam in the walls and ceiling plain never in the roof assembly. I wish there was a clear cut line on this, as our industry grows we can't have people doing things that are not in line with the codes or with our national trade organizations. |
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Posted: Dec 14, 2007 05:22 PM
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luke the spfa article was full of inconsistencies...and appeared to be written by folks with vested interests in the topic at hand... lets say i have a barrel vault with scissors trusses that are maybe ,,,hum,,,lets say 24" deep or so,,,so i should charge my general lets say $4 a foot or greater for a 4" cc application that would give him an r28 or so,,and have one hell of a time with the application,,,or should i apply lets say 10-12" of open cell for an r35 or there abouts (ok i shoot em to 15" cause the energy star r49 is what specs is)and i dont have to get up into the truss to do the application,,,and i can shoot it for maybe $3 or so a sq foot... now we havent even addressed the transitions from the scissors trusses to the adjoining flat lids,,,truely a custom application,,,block the ends as best you can and blow.. made for open cell foam,,,you would loose your ass doing it with cc.... if your argument is the moisture vapor issue... get wufi,,,or ham and do the work,,,model the wall or roof cavity and look at what it takes to achieve the performance neccesary.....physics is physics,,, you are right,,the 6" lift of OC in my cold climate area is not enough r value to prevent the transfer of hot to cold and the associated condensation that happens when such occurs... this is why i personsally shoot to greater depths....but some where out there in the 10-12" depth with OC's you are getting close to a vapor perm of less than 1,,,,and indeed have enough rvalue to keep the dewpoint away from the cold substrate,,, ...foamed me just like jelly roll,,and it foamed me.... |
