Recommendations/experiences with spray foam for existing shop

[gsganzer]

The place I'm purchasing has a 50'L x 40'W x 12'H metal shop. Unfortunately, it was built without insulation. I'd NEVER build a shop without insulation, regardless of climate. You can't even work in a metal shop in the Texas summer heat/sun, without feeling like you're in a broiler, plus you can get the sweating/condensing at other times. It looks like my only real option is to shoot it with closed cell foam, covering the sides and ceiling/roof. I'll get with a local company to get costs and decide on thickness, probably just 1-2 inches. 30' x 40' will remain as just a shop. Another 20' x 30' section will end up getting framed and insulated for a game/rec room/bunk house. I'd still need some foam on the metal to avoid sweating behind the walls.

Obviously, I'll make sure we cut in any additional doors/windows, weld any tabs if required to anchor the living space framing and complete any added electrical before I have it sprayed. I'll also paint any of the exposed foam in the shop side.

Any one have any issues/pointers with their shop foam?

 

[fidowanttobe]

I didn't go with foam, but I do know that when I was shopping for the shop build, there was a big difference in price amongst the spray foam bids so shop around.
One guy did say he was negotiable if I did most of the prep if your interested.

 

[grsthegreat]

We only have 1 company that does spray foam in my area, and his bid to do my 30x 40 x 12 shop pre covid was over 30k.

I paid 18k for the shop

It wasnt done.

 

[CH4Ohio]

Be sure the metal around your windows and doors is SCREWED down. Not unusual for the metal to just be laying in the "track" around windows especially. You need to push on the metal and anywhere that it's loose, put a screw in it. Othewise, when that foam hits it will expand out of the gap and bulge out the other side. You can trim it back, of course, but the metal is permanently pushed out a bit. You can also manually (by hand) just push on the metal outside as he sprays foam around the windows. It only takes a few seconds to let it grab. But if he squirts it into a gap, it will push out the other side and cause a bulge. (I learned this the hard way.) They can spray it over plastic or paper or tape, etc. so use anything to close up gaps and openings to the outside so it doesn't squirt through. You'll have a heavy solid surface on the inside wall and along all the framing, so you don't need it to fill crevices and gaps within the metal skin.

Chose not to spray the bottom of the roof panels and glad I didn't. Instead, we installed metal on the bottom of the trusses for a nice flat ceiling and I had cellulose blown in on top of that. "Attic" space above that is ventilated and my roof panels had the "condenstation stop" foam backing on them anyway.

Also, don't let them skimp on prep work like taping off and plastic drop coverings. That stuff is a real pain to clean off doors and glass, etc.

It sure does keep the heat out in the summer and heat in during the winter. The whole building is like a big igloo cooler.

 

[gsganzer]

CH4Ohio,
What thickness did you do?

 

[gsganzer]

We only have 1 company that does spray foam in my area, and his bid to do my 30x 40 x 12 shop pre covid was over 30k.

I paid 18k for the shop

It wasnt done.

We have quite a few contractors here that do it and Google-fu says costs should range from $1.75 to 4.50 a square foot for 2" thick. Looking at approx 4200 sq/ft so I've budgeted $15K.

It's not my preferred option, but I could always do vinyl faced fiberglass roll type. But then I'd have to remove the trim, remove the wall panels, apply the insulation and reattach the panels and trim.

I was amazed at how many homes we looked at that had uninsulated shops. In fact, the majority weren't insulated. If I was building this shop myself the first time, I would have used the roll insulation and then also put R-panels on the inside walls to 8', leaving the upper wall and roof insulation uncovered.

 

[ultrarunner]

Does foam degrade indoor air quality by off-gassing?

What about fire resistance?

 

[jyoutz]

The cheapest method might be to frame 2x4 walls inside of the shop and insulate will roll insulation and drywall it. That’s how I finished my concrete basement walls.

 

[Snobdds]

Flash and batt...

The benefit of spray foam is realized in the first 1" of the stuff. You get a vapor barrier, rigidity, and an air seal. Everything over 1" is just adding R Value. You can get cheaper forms of R Value. Then you add either fiberglass or some other batting to get the R value for the activities inside the shop.

To prevent internal condensation, you want the dew point inside the shop to be less than the dew point outside the shop. There are online calculators to figure out how much R value you need for that.

I had no idea how complex insulation is until I needed to insulate a cabin and later a shop. Then add in ventilation and it gets crazy.

 

[paulsharvey]

Only thing ill add, even 1" makes a world of difference over none. Sure, 4" might be nice, but it doesn't Have to be "nice", just workable is a huge improvement.

With that, im sure mobilization is probably a large portion of the cost; so 2" isnt 2x the cost of 1".

I would price 1" of close cell all the way around, and also price 2" roof and 1" wall. I know its only like R-3.5; but that and the air seal, makes a world of difference, enough that a window unit or two can keep it down to a comfortable 85 or so.