Spray foam is about to drive me crazy!

[mggreen]

Don't beat me up too bad guys, I have looked through the older post and still I just don't know what to do? My shop is 40x64x16, 2932 sq ft of wall space excluding overhead doors. A guy here locally ( fairly new to the foam) that does insulating gave me a price of a $1.50 for 4 in. of open cell/ sq. Ft. ( R15) and a price of $2.25 for 2 inches of closed cell/ sq ft. (R13). I'm going with a R50 in the attic $.55 sq. ft.
Well here is my delima: some say open cell some say closed cell. You hear guys talk about moisture getting in the open cell and then you smell mildew . The installer said he has been doing a lot of pole barns and pole barn houses staying 4-5 inches directly on the metal and he thinks open cell is my best bet. I just don't know. Help, opinions, answers gentlemen. Thanks, Mel

 

[Elginz]

open cell still needs a vapor barrier, and will absorb water. If that will not be a problem?

 

[yeldogt]

People use open for one reason .. it is cheaper.

Closed is a better product ... done correctly you will have no issues with closed.

 

[jawmaw]

I am doing the same thing and have decided on open cell only with a vapor barrier consisting of drywall with 1 coat primer and 2 coats latex paint. I have spent time reading about the standard practices in my climate and I think this method is the best option for me. My garage is 2x6 framing.

I have attached one of the documents I looked at in making my decision.

 

[Cjk]

I had 2" of closed cell sprayed on my pole barn walls last year and am very happy with it. The ceiling was 24" of cellulose for about R60. $2.25/sft for 2" isnt a bad price at all.
Last winters heat bill was less than expected.

 

[mggreen]

After I foam the walls ( which ever foam I decide to use) I am going to run purlins on the inside and put galvanized metal on the walls. Will that work as a vapor barrier?
Jawmaw , thanks for the attachment, interesting. Makes me think 4-5 inches would work fine with no problems.
Cjk, your in Wisconsin and 2 inches on the wall and happy with it, that speaks volumes to me. Anything else you can think of please let me know. My installer said they really don't like to do more than 2 inches of closed cell on the walls, not sure why?? But hell 3 inches might break the bank. I just want to do it right and enjoy my new shop this next winter.
Elginz, and yeldogt thanks.

 

[C2 Turbo]

I am building a house and in my location (Zone 4), I went with 10" open cell in all the roof decking/cathedral ceilings as well as garage ceilings

I also went with 6" open cell in all the exterior walls including the garage walls

Common walls between the garage/house, 5" open cell

The basement concrete wall got 1" closed cell

Basement garage ceiling underneath the master bed, once again, 5" open cell

To cut the humidity, I also installed an ERV system along with Geothermal

Wasn't convinced if I actually need a vapor barrier

 

[James-W]

Personally, of the two, I think closed foam would be the best. But everybody has to decide for themselves what they want for insulation and how much they want to spend.

 

[C2 Turbo]

It varies by the geographical areas. I would call 2-3 top insulating companies in the area and ask them for their advice.

I am sure weather is not the same around the country. Also I would say, the reputable insulating companies probably know lot more than us, the forum geeks, don't you think so

 

[theoldwizard1]

I will confuse you more !

The most "cost effective" solution is a combination. Closed cell foam sprayed in all corners and along all seams (maximum sealing) and then fill the void with fiberglass or, cheaper yet, blown in cellulose.

 

[Cjk]

After I foam the walls ( which ever foam I decide to use) I am going to run purlins on the inside and put galvanized metal on the walls. Will that work as a vapor barrier?
Jawmaw , thanks for the attachment, interesting. Makes me think 4-5 inches would work fine with no problems.
Cjk, your in Wisconsin and 2 inches on the wall and happy with it, that speaks volumes to me. Anything else you can think of please let me know. My installer said they really don't like to do more than 2 inches of closed cell on the walls, not sure why?? But hell 3 inches might break the bank. I just want to do it right and enjoy my new shop this next winter.
Elginz, and yeldogt thanks.

After 2" the pay back for being more efficient was a lot longer that just 2". My sprayer advised to go with 2" but would have done what I wanted as long as my checkbook was big enough lol.

 

[jacks2000]

I understand your confusion.
My builder (pole barn) almost insists on microfoil under the metal before spraying the foam. 2 reasons. 1 as a vapor barrier and 2 if you ever need to change the roof (due to a hail storm) you're pretty well screwed if you foamed direct to the metal. We're looking at 2" foam on the entire the roof and walls in the living section only. Spray-on cellulose on the shop walls and blown cellulose over the ceilings in the whole building. I will have duct and water lines in the attic.
Jack

 

[INTMD8]

I would be surprised if a metal roof with a few inches of closed cell sprayed directly to it could be damaged by hail.

I do see how replacing a panel if necessary could be rather difficult however.

 

[Bronson]

I would be surprised if a metal roof with a few inches of closed cell sprayed directly to it could be damaged by hail.

I do see how replacing a panel if necessary could be rather difficult however.

I have a 30x40 Mueller with 3-5 inches of closed cell on walls and ceiling.
After several large hailstorm in a ten-year span, not a dent.
The installer was training a new guy, so , I got a little thicker than normal job. No complaints, here.

 

[yeldogt]

I have done the hybrid in one project -- closed cell and then batts on a 2x6 wall.

Doing foam on the roof deck makes a huge difference.

IMO the properties of the closed make it a better product -- open is not something I would use.

 

[C2 Turbo]

I have done the hybrid in one project -- closed cell and then batts on a 2x6 wall.

Doing foam on the roof deck makes a huge difference.

IMO the properties of the closed make it a better product -- open is not something I would use.

I agree... Porsche 911 Turbo is a way better car. Anything else (Camaro, challenger/ Shelby GT 500/ZO6/GTR etc ) I would never buy

Joking aside: Open and closed foam both have their own applications and generalizing and saying closed is the only way to go is not a wise thing to say

May be we should ask the experts

http://www.greenbuildingadvisor.com...ng-blog/open-cell-foam-beats-closed-cell-foam

http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/weighing-merits-spray-foam-insulation

 

[mggreen]

My neighbor built a barn same size as mine and they ( not sure what it's called) put the packed cellulose in the walls and blew cellulose in the attic. The problem is I have heard that this could cause the metal to rust. They have metal on the outside, then cellulose, then metal on the inside. His shop was toasty this winter though. I still think I want some kind of foam. Thanks guys your opinions matter.

 

[yeldogt]

I agree... Porsche 911 Turbo is a way better car. Anything else (Camaro, challenger/ Shelby GT 500/ZO6/GTR etc ) I would never buy

Joking aside: Open and closed foam both have their own applications and generalizing and saying closed is the only way to go is not a wise thing to say

May be we should ask the experts

http://www.greenbuildingadvisor.com...ng-blog/open-cell-foam-beats-closed-cell-foam

http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/weighing-merits-spray-foam-insulation

There have been many issues with open foam in cold climates. While both foams require proper installation -- open is less forgiving. I don't like the extended off gassing with open foam. The r value, sealing properties and rigid nature of closed are all benefits that open needs help with.

Most of my projects have been rehabs with additions --- the sealing properties coupled with the insulation values at less depth are all reasons that I have always used it.


When building new -- providing open with all the protections can be achieved ...one would think ... but they have a cost.

I don't like the track record of open foam and osb - in cold climates with any humidity.


I don't agree with the older idea in your link with GBA -- it is also 6 years old and we have more information about open. The second link points out the main problem with open -- you need a lot of it and often the space is not available .. and without enough the moisture is a problem

 

[C2 Turbo]

.

I don't like the track record of open foam and osb - in cold climates with any humidity.

That's exactly what I said in my post, Geographical location. Up-north, may be closed is a better choice but in the south, open seems to do a good job too

Regardless of what type foam it is, it definitely is way better than the blown stuff.

 

[DC73]

It is definitely climate specific. Temperature, humidity and the possibility of condensation are all drivers in the decision.

Open cell is often the best choice for warm, dry climates. Closed cell can be used but at a higher cost which generally isn't worth any extra benefit in warm, dry climates.

Some cold climates are going to require closed cell only. However, in some climates, the best bang for the buck is to start with enough closed cell to avoid moisture movement and condensation issues and then finish with open cell or regular insulation.

You can also put foam panel insulation on top of the roof so you can use open cell underneath the decking but the calculation for how much foam goes on top is climate specific.

Most everyone installs open cell here in West Texas. If you can even find a closed cell applicator, the cost is prohibitive compared to open cell or other insulation.

DC

 

[BadgerBoilerMN]

DC has it right.

The vapor "barrier" in most construction is really just a retarder. If the steel were air-tight, it would be a vapor barrier; on the wrong side of the wall assembly.

The reason we use a vapor barrier in construction is simple to protect the wall insulation from getting, and staying wet. This is a cold weather phenomenon since the inside of the wall assembly must reach dew point and condense damp cold air leaving the inside of the wall holding the moisture and losing its R-value at the same time. Then of course there is the mold issue.

In steel buildings you will have a nearly perfect vapor barrier in the metal exterior more especially if you foam it. However, again in cold climates, if you can't dry the wall to the outside you must be able to dry it to the inside. If you are not dehudifying the inside you have no path for vapor. If you are not creating vapor, showering, cooking, etc. you have no vapor to get rid of.

I model many steel buildings for heating and cooling systems, most are in cold climates but a few are in the dry heat of the south west with many in high arid planes such as Albuquerque. In these places and many others, a radiant barrier makes sense, more especially on the south facing walls and roof. I am not talking about bubble foil--a nearly worthless product in any application--but rather rigid foil-face foam. If placed underneath corrugated steel you have natural convection to the ridge vent and may cut your cooling bill in half.

Here in Minnesota I started with a R-5 on all exterior, made air-tight with foam and then proceeded blow fiber-glass in netting with 5/8" rock on the inside. I actually had to take the plastic vapor barrier down, since my builder was not listening.
18" of cellulose sits on top of poly at the the 10' ceiling in this office area that will be cooled.

On the garage side it will be the same but for the lower design temperature and the lack of a vapor barrier, since the humidity will not be controlled and assumed to be the same as the exterior. I will be fiberglass to the inside of the R-5 foam.

Beware new foam applicators, since the quality of the foam depends on the skill of the man foaming both in mixing and in spraying. T

The reason 2" is preferred is because more than two inches can create enough heat to start fires. More can be applied after it cures. It is a great air-sealer and I used it from the rim-joist to the ridge-line in the 1921 balloon from farm house next door.

 

[mggreen]

Thanks Badger, I'm trying to get my head around all this.
I did talk with another company today. They are doing a lot of work locally. They told me they recommend doing a 3-4 inch spray of open cell at $1.60/ sq ft since I am going to put metal on the inside, R40 in the attic at $ 1.00 / sq ft.(local guy $.55 / sq ft)
My local guy is much cheaper but as you say Beware of new foam applicators. I need to look at some of his work. Still trying to make a decision. I appreciate all the input guys, thanks. Mel

 

[yeldogt]

DC has it right.

The vapor "barrier" in most construction is really just a retarder. If the steel were air-tight, it would be a vapor barrier; on the wrong side of the wall assembly.

The reason we use a vapor barrier in construction is simple to protect the wall insulation from getting, and staying wet. This is a cold weather phenomenon since the inside of the wall assembly must reach dew point and condense damp cold air leaving the inside of the wall holding the moisture and losing its R-value at the same time. Then of course there is the mold issue.

In steel buildings you will have a nearly perfect vapor barrier in the metal exterior more especially if you foam it. However, again in cold climates, if you can't dry the wall to the outside you must be able to dry it to the inside. If you are not dehudifying the inside you have no path for vapor. If you are not creating vapor, showering, cooking, etc. you have no vapor to get rid of.

I model many steel buildings for heating and cooling systems, most are in cold climates but a few are in the dry heat of the south west with many in high arid planes such as Albuquerque. In these places and many others, a radiant barrier makes sense, more especially on the south facing walls and roof. I am not talking about bubble foil--a nearly worthless product in any application--but rather rigid foil-face foam. If placed underneath corrugated steel you have natural convection to the ridge vent and may cut your cooling bill in half.

Here in Minnesota I started with a R-5 on all exterior, made air-tight with foam and then proceeded blow fiber-glass in netting with 5/8" rock on the inside. I actually had to take the plastic vapor barrier down, since my builder was not listening.
18" of cellulose sits on top of poly at the the 10' ceiling in this office area that will be cooled.

On the garage side it will be the same but for the lower design temperature and the lack of a vapor barrier, since the humidity will not be controlled and assumed to be the same as the exterior. I will be fiberglass to the inside of the R-5 foam.

Beware new foam applicators, since the quality of the foam depends on the skill of the man foaming both in mixing and in spraying. T

The reason 2" is preferred is because more than two inches can create enough heat to start fires. More can be applied after it cures. It is a great air-sealer and I used it from the rim-joist to the ridge-line in the 1921 balloon from farm house next door.

So you only go R5 with foam? or are you speaking of exterior insulated sheathing? And other than cost -- why not use foam on the roof or above ceiling? I think the foam/ batts is a great option ... we have contractors who love cellulose and others who have had problems? My current contractor in PA does not like it.

The OP was is in a cold climate -- my reference with closed vs open is directed that way.. Although, used closed when I built my house in a hot climate and the closed on the roof is amazing