Insulating Metal Garage Suggestions

[robsnyder22]

Hello All, I'm new to the forum (and read alot) and looking for suggestions to keep some heat out of my new carolina carport style building I had built (18'x25'x12'). I was going to sheet some 4*8 Styrofoam sheets to the roof to help keep the heat from radiating into the shed/garage but after reading what others suggested, they mentioned condensation could be an issue. I am in SouthWest Humid florida and looking to keep my workspace cooler without compromising the longevity of the building. Here are some pics, one was right after I built it and the last two was the temp difference between having the roof insulated and not (big difference). Oh the metal itself is 26 gauge and the framing is 12 gauge in case any of this is important. I do have a pretty large gable fan to pull the heat out of the building which helps but a lot of the heat seems to be radiating straight in from the roof. By the way the space is not air conditioned or heated in case this matters and not planning on cooling it in the future.

 

[Musicinabottle]

Best option, but not the cheapest is the sprayed on closed cell insulation. runs about $1.05 a foot. Other option which is best applied at the time of metal installation is the 2 inch vinyl backed insulation, used for pole buildings. So long as the temperature is the same inside as it is outside, providing ventilation via vents and or a fan, since you have no intention of heating or cooling the area, you wouldn't have any issues with condensation.

 

[djhnsn]

I am in the same boat as you. I also have a Carolina 24x30x12 in Tampa Bay. I was leaning towards a radiant barrier foam sheet in the roof.

That gable fan might work better on the far side of the building to pull the fresh air through the building. My thinking is it will just **** the air in the open door and blow it right back out the same end of the building.

 

[robsnyder22]

Good point about the fan but actually I have a side door on the opposite end where my workshop is thats 32*80 that I mostly use and leave open when running that fan so I get a decent flow of air when working in there. They have some closed cell diy kits on clearance at home depot but from what I understand the foam should be several inches thick to be an effective water vapor barrier correct? I would be more than happy to pay the $1.** a square foot for a decent layer of spray foam but from what I've seen around me a pro would want at least a grand to do the roof (haven't got an estimate, just guesstimating from Craigslist ads). Stupid question, having the 26 gauge steel on the roof, would that cause any issue with flexing upward when spray foamed with the expansion it does?

 

[djhnsn]

You wont have any expansion problems because 1 side is open there is no pressure.

My building is shaded by some large trees so the highest roof temp I have seen so far is 115 usually it is closer to 100. I don't have any doors or windows on the back so I get no airflow.

 

[abgiles]

I'm in the same boat, but just getting estimates. I'm in Jacksonville, and am building a 30x50x12, but I do have intentions of cooling and heating. By my calculations, including the roof, there will be a maximum of 4000 sq foot of surface area. The estimate I received for doing closed cell spray insulation was $8,250. That's over $2 per square foot. That's for a 2" thick layer of closed cell that they quote as having an R-13 value.

The kicker is that here, a 15 minute thermal barrier is required, which means everything must have drywall, 3/4" plywood, or.... they use a special intumescent paint coating to provide it, at a cost of $5,150. So, to meet code, I'd need to spend $13K. Yikes. Heading for a second opinion.

 

[ticklechicken]

I'm in the same boat, but just getting estimates. I'm in Jacksonville, and am building a 30x50x12, but I do have intentions of cooling and heating. By my calculations, including the roof, there will be a maximum of 4000 sq foot of surface area. The estimate I received for doing closed cell spray insulation was $8,250. That's over $2 per square foot. That's for a 2" thick layer of closed cell that they quote as having an R-13 value.

The kicker is that here, a 15 minute thermal barrier is required, which means everything must have drywall, 3/4" plywood, or.... they use a special intumescent paint coating to provide it, at a cost of $5,150. So, to meet code, I'd need to spend $13K. Yikes. Heading for a second opinion.

I'm a few hours south of you with a 24x45x10. I just paid $6k for closed cell, 2" on the walls and 3" on the ceiling. After that, I did furring strips and 3/4" plywood on the walls. I did that myself for about $2k using nice quality plywood. Nice enough that I could stain it instead of paint.

 

[abgiles]

I'm a few hours south of you with a 24x45x10. I just paid $6k for closed cell, 2" on the walls and 3" on the ceiling. After that, I did furring strips and 3/4" plywood on the walls. I did that myself for about $2k using nice quality plywood. Nice enough that I could stain it instead of paint.

I'll definitely be doing something of that nature, either the plywood or sheetrock, but since it's a workshop, thinking the plywood would be a better choice.