Closed Cell VS Open Cell spray foam insulation?

[Repsolracer22]

Ive all but decided on the expensive spray foam insulation in my 40x60. Anyone has opinions on this closed cell VS open argument? Closed is more expensive but is much more ridgid and actually provides some additional strength to your structure. But its so tight and im wondering if you can develop mold because of the lack of fresh air exchange?

so maybe open cel is better all around?

 

[yeldogt]

You don't pick based on fresh air exchange -- the open is more permeable to water vapor -- you are still stopping air movement enough with both that some form of internal ventilation will be needed ...... and maybe dehumidification.

The issue with open cell is that you must have it thick enough to stop air/ water flow so the water vapor from the dwelling does not condense on the wood sheathing.

With closed cell foam it needs to be thick enough so that you don't get the water vapor condensing on the inside of the foam.

The problem with the open is that the rafters on some building are not deep enough to achieve the required thickness.

I have always used closed -- great stuff

 

[Repsolracer22]

so what should it cost roughly for closed cell? forget the ceiling for now. just walls. 40x60x12

my inclination is to go with closed cell. but i know its stupid expensive. and how thick is it 'suppose' to be to perform well? or can you negotiate the thickness?

 

[srt4geezer]

closed cell=moisture isn't a problem. Open cell=mildew will become your signature odor. Fin

 

[kj_mustang]

closed cell is roughly $1.00 per inch thickness per square foot covered. Getting quotes from qualified contractors in your area is the only way to get a correct cost.

 

[purplezr2]

closed cell is roughly $1.00 per inch thickness per square foot covered. Getting quotes from qualified contractors in your area is the only way to get a correct cost.

This is almost spot on. I had a crawl space done. 666 sqft and it cost 1400 dollars.

 

[Repsolracer22]

talked to a guy the other day that quoted $8900 for closed cell spray foam. 1.5" thickness in walls and 2" in roof. 40x60x12 with 2 10x10 bay doors.

i told the guy i assumed spraying the ceiling was better then spraying the roof, but he seemed to disagree.

so the calculation was ~2200 sq ft total for walls at $3780
and roof ~4920 sq.ft at $5170

 

[Tazzie]

Had my pole building sprayed with closed cell 3" on celling and 1.5" on wall. The best thing that I have done. Sealed the building up very well.

 

[theoldwizard1]

Sponges are open cell. They hold water/

 

[Repsolracer22]

Had my pole building sprayed with closed cell 3" on celling and 1.5" on wall. The best thing that I have done. Sealed the building up very well.

How big is your building? What did it cost? And in the ceiling area, did you spray it on the ceiling or the back side of the roof? What kind of heat do you use?


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[SchuLace]

My parents added on a 4 season room and used closed cell. I think the room is 14x16 with 8 ft walls and vaulted ceilings that the peak is around 13 feet. They paid around $2600 I believe for the walls, ceiling and underneath the floor outside. It's a 2nd story room.

 

[Repsolracer22]

anyone hear about Spray Foam and it being toxic? There's a good amount of stuff on thenet talking about 'outgassing' and other issues with the foam. Of course you dont want to be in the shop for a couple days after it is initially sprayed, but that's not what im talking about.

aparently, if the foam solution isnt mixed exactly a certain way, it can be toxic. It can continue to outgas especially if its on the inside of bare metal and it gets really hot.

not sure but sounds somewhat legit.

 

[Randy in Maine]

99% of any outgassing will be done in 2 days. The pros know how to do "the mix" anymore.

Closed cell spray foam is money well spent. I don't think anyone uses fibergalss around here any more on tight quality construction.

 

[Repsolracer22]

thats what they initially tell you ...... however,

if you look around a little bit, there's plenty of evidence that suggests otherwise. trust me, i like the idea of spray foam and probably will spring for it. but just skeptical. asbestos was an awesome thing too, until it wasnt.

some say that it can still outgas after its sprayed. for example, if you get it sprayed now, in october. well we wont have any sun BEATING on that metal building with that foam on the other side until maybe june next year. so people/agencies have suggested that when that foam gets to BAKING it can release toxic gases/fumes

ive also read that it can shrink and even peel off of metal. but again, a lot of that could have to do with the way its applied too. just gathering opinions here. seeing if anyone has heard any bad stuff other then the high cost

 

[Randy in Maine]

Closed cell spray foam is nothing like asbestos. That is not an acurate comparison.

It is a little stinky as it gets sprayed in, but that goes away in about 48 hours with the windows open and fan ventilating. Heat does not have anything to do with it.

Have a professional guy do it as he is set up to do it correctly.

What you cover the foam with is important to consider as it will burn if exposed to a fire.

 

[saundersdiesel]

Would you consider closed cell foam a good enough insulator for a 12x40 garage that sees temps in a -20s and still needs to be workable in the winter at those temps?

 

[kj_mustang]

Would you consider closed cell foam a good enough insulator for a 12x40 garage that sees temps in a -20s and still needs to be workable in the winter at those temps?

Put on thick enough, yes.
I can say that my spray foamed building put off some smell for a few weeks. The foam was exposed to this summer's heat and sheetrock was just hung about a month ago. I have not smelled anything for several months.

 

[Repsolracer22]

Should my building have any kind of building wrap vapor barrier first? Or does the foam just go right to the inside tin? Are there any advantages to NOT spraying directly onto the metal tin on inside? Like putting up plywood all around and spraying to that instead of to metal?


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[kj_mustang]

If you spray at least 2" of closed cell directly to the metal, you do not need a separate vapor barrier. It will also be a wind/draft barrier.

 

[Repsolracer22]

what about the roof vs ceiling argument?

some installers suggest to put up the tin ceiling first, and spraying foam on back of ceiling. they say this makes sense because there's no point in 'conditioning' the attic space.

other installers say that's completely stupid, and doesn't work the way you think it works. they say you need to spray the backside of the roof tin instead. AND they said you need spray & seal up the soffets and ridge vents. I asked why this makes sense to essentially be conditioning the attic space. He said it wouldn't do that.

interesting debate.

 

[kj_mustang]

If you will have any hvac equipment in the attic, then there is an advantage to having an unvented and conditioned air space attic. The argument about conditioned attic is usually how it is conditioned. Some say enough air leaks from ducts and heat rises through the ceiling to condition the space, but others say you need to have supply and return lines to the space. If you have no equipment and you already have a vented attic, then my opinion would be to insulate at the ceiling.

 

[Rlastr]

My shop is 52'x56' with 2x6 framing, tyvek wrapped OSB and board n batten siding - I sprayed 2" of closed cell foam and filled the space with fiberglass batts. The shop also has radiant floor heating. I purchased 4 DYI green foam kits from CL for $1,400 and guessing less than $1,000 in fiberglass.

I will be testing all the walls this winter and hope all goes well.

You can see the green foam over the highbay doors.

 

[yeldogt]

The big loss of heat in any building is through the top ceiling -- and the reason for ventilation above is to remove any moisture that leaks through. And a lot of heat and moisture leaks through. If you do the roof deck -- that ends it ....you can use the space above for storage equipment.

Most people -- even when they foam a ceiling still try and use the space above -- so it's not sealed?

 

[Tazzie]

Building is 40x40x14 with metal roof and sides the foam is sprayed directly on the metal. I am using a 30' radiant tube heater. The only loss of heat is in the two overhead doors. 12x12 and a 10x10 hope this helps.

 

[Repsolracer22]

so it seems like people are saying that spraying closed cell foam directly on the backside of the ROOF metal is the way to go? Completely sealing the ridge vent and soffets etc etc? But this could change depending on what i plan to do for heating?

 

[LX-Markham]

Just did my garage with closed cell foam, sprayed directly to the wall and roof sheathing . It smelled for a few days, but it's gone now. I will be installing drywall in the spring.

 

[Repsolracer22]

Assuming they sealed up the soffets and ridge vents? How thick did they do on the walls VS the roof deck?


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[Randy in Maine]

Just did my garage with closed cell foam, sprayed directly to the wall and roof sheathing . It smelled for a few days, but it's gone now. I will be installing drywall in the spring.

Money well spent. You cannot beat high density foam.

 

[LX-Markham]

Assuming they sealed up the soffets and ridge vents? How thick did they do on the walls VS the roof deck?

I believe they put 2.5-3" on the walls, and 3.5-4" on the ceiling.

Yes, we sealed up the soffit vents. There was no ridge vent.
Problem using batt insulation and a vented roof system was going to be getting supply air to the right side of the roof where I share a common wall with my neighbor. Spray foam and no venting was the easy solution.

 

[Repsolracer22]

I believe they put 2.5-3" on the walls, and 3.5-4" on the ceiling.

Yes, we sealed up the soffit vents. There was no ridge vent.
Problem using batt insulation and a vented roof system was going to be getting supply air to the right side of the roof where I share a common wall with my neighbor. Spray foam and no venting was the easy solution.

are you sure it was that much foam? local guy here in MD is quoting 1.5" on walls and 2" on roof. and says that's plenty of foam. But seems like he's skimping me a bit.

this is a 40x60x12. and when i ask people for 2" on walls and 3" on roof the estimates are like $12-$13,000

 

[Cjk]

My pole barn shop is 50x72x16'. I had 2" closed cell sprayed on the inside of the exterior steel walls and blew cellulose in the ceiling to R60. Building is heated with radiant tubes in the concrete floor. So far I am very happy with it.

 

[Repsolracer22]

My pole barn shop is 50x72x16'. I had 2" closed cell sprayed on the inside of the exterior steel walls and blew cellulose in the ceiling to R60. Building is heated with radiant tubes in the concrete floor. So far I am very happy with it.

you added a ceiling im assuming and then blew cellulose on top of the ceiling? And then you left the roof deck just bare correct? So im also assuming you have the ridge vent and soffets so attic can breath?

 

[LX-Markham]

are you sure it was that much foam? local guy here in MD is quoting 1.5" on walls and 2" on roof. and says that's plenty of foam. But seems like he's skimping me a bit.

this is a 40x60x12. and when i ask people for 2" on walls and 3" on roof the estimates are like $12-$13,000

It's a 20x20 garage, and we sprayed about 3800 board ft.
It's at least 2" on the wall and 3" on the roof.

It is Canada afterall

 

[Cjk]

you added a ceiling im assuming and then blew cellulose on top of the ceiling? And then you left the roof deck just bare correct? So im also assuming you have the ridge vent and soffets so attic can breath?

Correct. Steel was hung on the ceiling with a vapor barrier, baffles were palced on the sides to keep the cellulose out of the soffits, then celluose was blown up there.

 

[dwegner]

Correct. Steel was hung on the ceiling with a vapor barrier, baffles were palced on the sides to keep the cellulose out of the soffits, then celluose was blown up there.

I am thinking of doing the same thing but with blown in fiberglass. Do you really need the vapor barrier? My builder is concerned about how noisy the bare metal roof will be.

 

[Repsolracer22]

Blown cellulose is good for sound deadening.


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