# Let's talk INSULATION



## reikimaster (Sep 29, 2005)

OK, been looking at insulating my shop, 16x18 space. Need to insulate roof and 3 of the walls. Roof is 2x4 trusses on 24 inch centers. Walls are 2x4 on 16 centers. 

I calculated the price of materials for an R-8.9 result using polyisocyanurate sheets. Would cost about $260

If I use Roxul, which gives me an R-15 result, I could do it for about $250 including running the extruded vent/spacer from eaves to ridge inside each truss bay.

For the walls, I looked at the UltraTouch (cotton/denim) and that was going to run around $468.
Regular old kraft faced fiberglass would only cost me about $100. (10 rolls, 32ft long each).

Kinda looking like I'm headed toward Roxul for the roof and plain old fiberglass for the walls.

Any thoughts?


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## Gene Howe (Jul 10, 2007)

Hi Charlie,
I'd guess your main concern is keeping cool, right? 
There is a foil backed fiberglass batt that might be better in the ceiling and, even on a wall that get's direct sun. 
Not sure, but I believe there is an insulating foam board with reflective backing, too.
Does the shop have a gable vent? One at each end would help. We have them in our house and, with a whole house fan blowing into the attic, we get by in sunny AZ without A/C except on the hottest days.


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## reikimaster (Sep 29, 2005)

Gene Howe said:


> Hi Charlie,
> I'd guess your main concern is keeping cool, right?
> There is a foil backed fiberglass batt that might be better in the ceiling and, even on a wall that get's direct sun.
> Not sure, but I believe there is an insulating foam board with reflective backing, too.
> Does the shop have a gable vent? One at each end would help. We have them in our house and, with a whole house fan blowing into the attic, we get by in sunny AZ without A/C except on the hottest days.


Gene, I can't find fiberglass for 24 inch spaced, 2x4 trusses that have any facing on them at all. Gable end vents, yes and soffit vents. I was going to insulate up to within a foot or 2 of the peak and then create a hot box at the peak inside. A place where hot air traveling up the roof decking inside, can go up between the deck and insulation and get to near the peak. Then I was going to power vent that hot box if the gable vents alone don't handle it. 

So... cool in summer, yes. And warm in winter. Kind of a mix here in western New York state. Today was 88 degrees, sunny, and humid. I couldn't even work in the shop. Only in the morning or maybe now that it's after 8pm I might be able to get in there.


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## papawd (Jan 5, 2011)

I built a false ceiling in my shed and put rolled fiberglass covered with the blue 4'x8' sheets also did the walls with rolled fiberglass and it still gets 90-100 degrees Farenheit for the last month and that is with 2 fans and a small window unit running... I work in there in morning till about noon and then sometimes in the evening after sun goes down , although this weekend I did do some work during the day but had to have the fans blowin straight on me


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## N'awlins77 (Feb 25, 2011)

My shop is 10x16. I've got Owens Corning, I think R15 unfaced in the attic, faced in the walls. Then unlike probably most of y'alls, I'm off the ground, so between my subfloor and my 1/2 ply floor, I've got 2 layers of roofing felt paper I had left over. All my corners are sealed with silicone. My exterior walls are 5/8th T1-11. I have windows, but no glass. I live here in south louisiana. Under my patio it's been around 105 or so. I have a small window unit in my shop. If I were to go in there, in the middle of sunny day to just sit down and maybe do some drafting or design sketches, I don't even have to turn the a.c. on. If I'm going to actually work, I put the a.c. on high for a few minutes, then I've got to put it on low for the duration of my stay in the shed, or get a sweater!!.


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## papawd (Jan 5, 2011)

maybe I need something under my floor , I too am off the ground


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