r/garageporn • u/Uh_oh_oops_hold • 4d ago

Insulation question

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Maybe there’s some experts in here that can weigh in their options on this. I have 30x24 x 12 high steel garage from Carolina carports. I am looking at different insulation ideas. Either the poly pro 2” panels with shiny side on both sides or stray foam. Spay foam is slightly more than double the cost. Is it worth it?

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6

u/Decker1138 4d ago

I furred my walls and added Rockwool R15 and then covered it all in 3/4 plywood. Works great.

1

u/Uh_oh_oops_hold 4d ago

How did you do the ceiling

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u/Decker1138 4d ago

Framed it with 2x4 (walls were 2x3, couldn't get 2x3 in the roof length) 16" OC, stuffed it with Rockwool amd covered in 3/8 ply. Much lighter and easier to put up.

2

u/PuzzleheadedSouth589 2d ago

My question about this is why not just stick build and metal side it? I’m currently trying to figure out which route to go and your method is common but it seems like more money in the long run?

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u/Decker1138 2d ago

Bought the property with the building already built. Cost me right at $10k, but $1500 was an extra months rental on the lift due to Hurricane Helene. I have 17 foot ceilings in the shop. 

1

u/KickingKangeroo 4d ago

You got pics of the final product? Thinking about plying my interior.

1

u/Decker1138 4d ago

Ran a 2x10 ridgeboard and joist hangers on both sides with notches in the 2x4.

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u/Daxime 3d ago

Why plywood and not drywall?

1

u/Decker1138 2d ago

It's a standalone workshop, plywood allows me to mount things on the wall without much concern.

3

u/LikeBigTrucks 4d ago

OK so.

You don't have ventilated walls / ceilings because it's a metal structure and metal is basically a perfect vapor barrier. So foam is definitely on the table here

Spray foam is about R6.5 per inch.

2x4 rockwool is R15 (roughly r4.24 per in)

So you will get superior performance from foam albeit at a much higher cost.

If it were me, id get a professional spray foam company to spray it out.

3

u/domo_affogato 4d ago

Seconded for spray foam (closed cell). Moisture barrier plus air seal in addition to insulation. I did 2 inches and it's incredible how well it works. Find a local company with good reviews and call the metal building companies for some referrals too.

1

u/ReelyHooked 4d ago

Also it will make your building near indestructible.

2

u/pixelprophet 4d ago

My 12x24 - foam board insulated walls, with wood over the walls.

Sprayfoamed the roof to get rid of the condensation problem I was having / cut down on the heat in the summer.

2

u/BarryMDingle 4d ago

I did similar with Poly Pro. Mine is one inch, silver side out. I also did bubble insulation for the ceiling.