Spray foaming shop?

[Lme]

Just finished my 60x80 shop and looking at insulation options. It will have heated concrete via wood boiler. Looking at doing open cell spray foam in the propane looking cans. How effective is it? What is a sufficient amount on walls and ceiling?

 

[Seasoned Oak]

Just finished my 60x80 shop and looking at insulation options. It will have heated concrete via wood boiler. Looking at doing open cell spray foam in the propane looking cans. How effective is it? What is a sufficient amount on walls and ceiling?

I think the foam panels are much cheaper, every time i look at spray foam the price makes my head spin. I usually do blown in ,if possible ,but foam panels are the next best option.

 

[Highbeam]

Too much money. Not worth it in an open shop type application. You will find that you can get better R-value and easier installation with traditional products. I used R21 batts in the walls and R-50 cellulose blown into the attic of my 30x60 shop.

More important is proper air sealing.

 

[dja950]

Airsealing is what the foam does well. I'd recommend one inch to 1.5 inches of closed cell foam on the walls. That's give u r7 to r10 with a complete air seal which is greater than most people's homes. A r19 batt loses 30 percent of its r value due to air gaps around it. Impossible to cut/fit perfect and no seal. Plus you'd have to stud out the walls which is time and money, spray foam you'd apply right to the metal. I just built a 40x60 myself. For the ceiling I'm doing blown in. Not much of a cost benefit to foaming up there. Cheaper to blow in up there.


Also I'd strongly recommend calling a contractor. Ud be surprised how much cheaper it is to have someone else do it. Those "propane cylinder" kits are for small jobs that contractors don't want to do wel because their so small it's not worth it.... They cost anywhere from 1.20 to 2 bucks a board ft (1 sq ft 1 in thick) depending on what size kit.I'm a Sprayfoam contractor and for easy jobs like a barn we charge .90 a board foot. Cheaper than what u can buy the kits for and someone else is doing it. Open cell I wouldn't recommend for a barn because it's very brittle, closed cell when cured is rock hard. Also improves the structural support...a lot of Contractors push open cell because they make more money due to higher yields. closed cell per board foot with equal r values is only 5 to 10 cents more. Open cell is roughly .40 a board ft where like I said earlier closed is roughly .90. Way better product in many aspects for only .10 cents more for equal r values.

 

[dja950]

Long story short in the ceiling id defiantly do blown in. To avoid hassle of studding out the entire structure which wouldn't be cheap id suggest getting an estimate for a contractor to do the foam and compare. Probably be somewhere around .90 cents a sq ft per inch. I dont know your ceiling heights or size of doors and how many other wise i could do it for you.

 

[Lme]

I'm still debating putting steel on the ceiling or leaving it open truss. A. My budget is about maxed. B. there will be trucks in and out and the white steel gets black from exhaust.

I am leaning toward spray foam in hopes to seal the building

 

[dja950]

60x80 depending on the roof pitch will cost a lot to spray foam. Well over 5k sqft at 2inches thick is over 10k board feet. I'd bid that at .85 cents a board foot being such a large job.... A job this size would require a lot of those "propane tank" kits. Biggest ones I've seen are 600 board feet. I've used them on small jobs where it wasn't worth dragging the rig along, and they do that just as they are intended, small jobs. They're expensive

 

[jebatty]

LME, did you insulate under the entire slab and especially 4 feet or so vertical around the perimeter. Frost creeping in and freezing under the slab is a huge heat sink.

 

[velvetfoot]

You keep the sprayed on foam exposed on the walls?

 

[Highbeam]

You keep the sprayed on foam exposed on the walls?

Not legally. It's a huge fire hazard.

 

[Highbeam]

Airsealing is what the foam does well. I'd recommend one inch to 1.5 inches of closed cell foam on the walls. That's give u r7 to r10 with a complete air seal which is greater than most people's homes. A r19 batt loses 30 percent of its r value due to air gaps around it. Impossible to cut/fit perfect and no seal. Plus you'd have to stud out the walls which is time and money, spray foam you'd apply right to the metal.

Obviously as a spray foam contractor you're biased. I agree that spray foam is superior in every way except for the ridiculous cost. However, you are obviously wrong about the FG batt insulation loosing 30% of R-value due to air gaps. That doesn't even make sense. R-value of a material has nothing to do with whether the installer properly installs it.

Another slick thing that folks are doing with pole barns is stapling up a net type product and then blowing in cellulose.

I studded out the walls between my poles and built a proper FG batted wall just like a house. It is not expensive to stud the walls out. You can buy very wide fiberglass batts too which will allow you to minimize or eliminate the additional framing. But really, you want to add a surface anyway so having those studs provides a place to attach the sheeting on the inside.

 

[velvetfoot]

Well, if we're talking about avoiding building walls, what's the substitute, some kind of spray on stuff? It's only a shop, but would that look be good?

 

[dja950]

Not legally. It's a huge fire hazard.

They make a paint like product that you use a paint sprayer and apply it over.

R value is very misleading. It's determined by measuring conduction. Heat transfers three ways, and r value only measures one. You're trying to tell me there's no gaps between a stud and a the batt? Air and heat will be lost around that area... Foam creates a continuous unbroken barrier... Im not biased I have no stake in this project I'm not making anything on it. I'm giving my opinion and that's it...
But that is also a good idea, that fiber stranded poly attached to the posts then blowing in behind it. wouldn't be the best but would be better than nothing. I guess it depends on how much the building is being heated. If being heated a lot the payback in heat savings might pay for the foam. If a weekend warrior project and only heating it every now and again than a cheaper alternative would be better. Every scenario is different and you have to look at return on investment.... I also do blown in and to be honest as a contractor i prefer it. Way less headaches and make the same money per job so I'm not really biased like you think.

 

[Highbeam]

You're trying to tell me there's no gaps between a stud and a the batt? Air and heat will be lost around that area

Correct. No gaps. Look at my framing work, this is a job done as well as possible. If you hire this job out you may not get as good of a job. The spray foam is superior for sure but wow, the cost! If you properly air seal the wall then the only losses you have from gaps are the actual loss of R-value on that gap. If you miss 30% of the wall then you're an idiot. Start with properly spaced framing members. Like I said, you can buy wide rolls of FG, like 8' wide for cheap. Pole barn companies (Morton) sell them.

On top of those batts with VB stapled for an air seal, I installed the OSB with sealed edges, that's right, caulk all around. The ceiling has 6 mil plastic sealed and overlapping the wall batts two feet. Then R-50 cellulose blown in on top of the metal ceiling, I think it was 158 bales, brutal. The real problem, the only thing you can't fix, is the overhead doors. Those buggers are the enemy of an air sealed project.

R-value is a valuable measurement. It is used for conduction losses when you properly air seal a job with another technology. Foam combines the R-value with an air seal and is very good at it but you can't compare spray foam to only a poorly insulated batt.

 

[Highbeam]

Well, if we're talking about avoiding building walls, what's the substitute, some kind of spray on stuff? It's only a shop, but would that look be good?

Do you want an insulated wall or not? You need to and want to protect that insulation and the outside (metal) of the wall from damage from the inside. There are roll products that provide some benefit. Usually FG with a white vinyl coating to the inside.

I'll try and find some photos of options.

 

[dja950]

Correct. No gaps. Look at my framing work, this is a job done as well as possible. If you hire this job out you may not get as good of a job. The spray foam is superior for sure but wow, the cost! If you properly air seal the wall then the only losses you have from gaps are the actual loss of R-value on that gap. If you miss 30% of the wall then you're an idiot. Start with properly spaced framing members. Like I said, you can buy wide rolls of FG, like 8' wide for cheap. Pole barn companies (Morton) sell them.

On top of those batts with VB stapled for an air seal, I installed the OSB with sealed edges, that's right, caulk all around. The ceiling has 6 mil plastic sealed and overlapping the wall batts two feet. Then R-50 cellulose blown in on top of the metal ceiling, I think it was 158 bales, brutal. The real problem, the only thing you can't fix, is the overhead doors. Those buggers are the enemy of an air sealed project.

R-value is a valuable measurement. It is used for conduction losses when you properly air seal a job with another technology. Foam combines the R-value with an air seal and is very good at it but you can't compare spray foam to only a poorly insulated batt.

Did you staple every millimeter of that batt to the stud? Cuz that's where the small gaps are that people don't consider With the air infiltration. Sure the heats not getting through the center of that batt but around those edges where it's not sealed to the stud is where it's coming through. Ever look at a infrared image of a house with batts and one with foam?

Is osb as interior sheathing code?

 

[dja950]

Like I said I'm not trying to tell you what to do.... But this is my opinion. Factor in the cost and time to stud out the walls plus the fiberglass and your time to install it because it sounds like your running a business and time is money. There's jobs I could do but hire out because i can pay someone else less than what I can make doing my own trade. then compare that to .85 cents a board foot. Compare the cost differences. If foams way more then don't go that route, if they're close then I'd do it.

 

[Highbeam]

Here's a link to some photos of batts without full framing.

http://www.garagejournal.com/forum/showthread.php?t=85681

And here's one for spray foam. Not that he is face nailing girts to the poles to add a sheeted wall covering to protect the foam. Foam is the Cadillac option for sure.

http://garagejournal.com/forum/showthread.php?t=230875&showall=1

Did you staple every millimeter of that batt to the stud? Cuz that's where the small gaps are that people don't consider With the air infiltration. Sure the heats not getting through the center of that batt but around those edges where it's not sealed to the stud is where it's coming through. Ever look at a infrared image of a house with batts and one with foam?

Is osb as interior sheathing code?

The batt VB is stapled to face of stud, then overlapped by the next batt's VB and stapled. That double lap is on every millimeter, and then the OSB is screwed tight and sealed which compresses the double VB below it to make it air tight and the OSB itself is air tight for yet another barrier. This is all for air infiltration, not for R-value. If you didn't think that you had enough skill to properly attach the batt's VB then you could instead cover unfaced batts with plastic as is common in Canada. Air seal is more important than R-value, get it right. Then R-value can be done many ways.

I have looked at IR images of houses with batts and saw those lines at every stud. That is almost never caused by poor installation of insulation, it's called thermal bridging and is due to the warm framing members. You'll see it with spray foam houses that have wood framing bridging the wall cavity as well.

Foam does a lot of things very well. You don't need to invent deficiencies in other methods to prove that.

The OSB is legal in a detached garage.

 

[Lme]

Framing walls is absolutely not a consideration considering I have 18ft sidewalks that would be a huge chore. I have plastic under concrete but no insulation, however do plan to put foam around edge.

 

[Lme]

The cheapest kits I've found are .72 sq ft @ 1" and that's if you buy about 6 kits. Foam board runs about 1.15 sq ft @ 2" but then need to seal around ever sheet. The shop is mainly to park trucks and occasionally do repairs. I spent a large portion of my funds on space because that was most important. My wood source is virtually free with minimal effort, that being said it's hard for me to see an expense savings in the long run. The finish from here on out is based on available funds (cash on hand)

 

[Highbeam]

Framing walls is absolutely not a consideration considering I have 18ft sidewalks that would be a huge chore. I have plastic under concrete but no insulation, however do plan to put foam around edge.

Wow, heated concrete in South Dakota with no slab insulation? You will be well rewarded by putting that perimeter foam in.

 

[dja950]

The cheapest kits I've found are .72 sq ft @ 1" and that's if you buy about 6 kits. Foam board runs about 1.15 sq ft @ 2" but then need to seal around ever sheet. The shop is mainly to park trucks and occasionally do repairs. I spent a large portion of my funds on space because that was most important. My wood source is virtually free with minimal effort, that being said it's hard for me to see an expense savings in the long run. The finish from here on out is based on available funds (cash on hand)

If your primary goal is cheap and not worried as much about heat loss, maybe spend the money on running metal panels or some type of sheathing to the 6x6 posts and blowin in cellulose from the top down, the savings from not foaming would pay for the metal at 2.00 a linear foot. Cellulose bags in bulk can be had for 9 bucks a bag. 5.5 inches of cellulose would be r15 roughly. It'd settle but just re do it after is settled to touch it up. Just blow on between the 2x12 headers.... If u wanted something temporary and cheap use fiber stranded 6mil poly and tack it to the 6x6s and blow cellulose behind it then put up your interior sheathing later over the poly. That fiber stranded stuff is meant for temporary walls and such. It's about 150 bucks for 20x100 roll and there is many different size options. I mean I can come up with a lot of different ideas for budget levels some prettier than others. The thing is going with a lesser option now can bite you later. Sometimes best option is to wait until you can afford what you really want.

If u do the foam option id recommend getting 2 or 3 estimates. Doesn't cost a thing maybe someone can surprise and come back at .80 a board ft. For .8 cents might be worth it for them to do it.

Just throwing out options not trying to persuade anyone or argue... Some people get very defensive when you disagree with their way. I honestly think fiberglass batts are the worst option, it's just prone to moisture and air leakage. not bad mouthing it and making stuff up I've been accused.. I do all types of insulation, I make the same profit any all the work. Like I said already blown in is my favorite to do, way easier way less things to go wrong.

In my own house I just built did 4in of closed cell in walls, 1 in on the ceiling and r60 fiberglass blown in over the top.

In my 40x60 barn. 1.5 inches closed cell on the walls because framing it in wasn't going to happen, and I'm blowing in 100 bags in the ceiling. Only going to be heated when I'm out there with a 90k btu coal stove. Figure I'd start it up the night before I wanted to work out there and should be toasty by morning.

 

[Highbeam]

I honestly think fiberglass batts are the worst option, it's just prone to moisture and air leakage. not bad mouthing it and making stuff up I've been accused..

You. That fiberglass sure does leak moisture eh? 30% reduction in R-value too.

Batted insulation is way harder to install properly than sprayed or blown. That's an honest fact. It takes some skill and patience to do batts right.

 

[dja950]

You. That fiberglass sure does leak moisture eh? 30% reduction in R-value too.

Batted insulation is way harder to install properly than sprayed or blown. That's an honest fact. It takes some skill and patience to do batts right.

Moisture and air leakage were two separate points sorry my grammar wasn't on point.

I strongly suggest reading studies about fiberglass and its downfalls. In a lab setting it's great in real world scenarios it's not. when they do the r value tests it's in a vaccum with no air at 75 degrees.

Another misconception about foam is not being able to run wire after which is far from fact. With closed cell you get r21 at three inches. In a 2x6 wall that leaves u 2.5 inches to do whatever you please afterward...

 

[iamlucky13]

30% loss sounds way too high for batt insulation unless perhaps you're assuming no air sealing. In which case, it's not really the batt that is the problem, but the improper install. The batt itself doesn't provide the sealing, so you have to do it separately.

What I've seen commonly done in sheet metal sheathed buildings is a plastic liner material placed over the batts to more or less eliminate infiltration.

The new 110' x 270' shop at my work is insulated with rigid panels that have a z-lap at each edge to help seal those joints, and cut seems are taped over. They're made from polyurethane and have an R-value of 7.3/inch, which is really high. They're flame and structural rated so they don't need to be covered. In fact, the way this building is assembled, they first placed the insulation over the skeleton and fastened the sheet metal over the insulation (I'm not sure if they used really long screws, or if the insulation actually supports the sheet metal.

However, I'm pretty sure those panels are really expensive.

Framing walls is absolutely not a consideration considering I have 18ft sidewalks that would be a huge chore.

Any method of insulating 18' high walls is going to be a huge chore. Sealing and framing out for batts is probably one of the most labor intensive options, but I'm also pretty sure it's one of the lowest material cost options.

Also, what about radiant overhead heaters? They can be effective in large open spaces because the radiant heat helps keep your body temperature up even if the air temperature is cooler. I think some versions can be integrated with a boiler. They also can potentially work well in intermittently occupied spaces because you can leave the temperature really low when unoccupied, since you start feeling perceptible heat very quickly after they're turned on, rather than waiting for the air to start warming up.