Insulating garage (pole building type)

[KongZ TT GT28RS MD]

I have a 26x30 garage that I want to insulate, cheaply..

I was thinking of using the 4x8 foam board type (owening corning pink)

I found this stuff for $5 a sheet for the 1.5" thickness. The R rating is "R-7.5".

Is this worth it? The boards are supposed to be around $28/sheet.

I'm interested in using this because it would not be necessary to stud out my garage with this type of insulation. And I can cut the sheets to fit in behind my garage door slots.

I love to get a good deal and really don't want to pass this up, But is this worth it with the "R-rating" being only a 7.5?

Doing it cheap and effective as possible is important to me because I am planning on building an addition later one, which I can "do it right" with batts type insulation then. I do mechanic work on the side.

I have a LOPI (pioneer) pellet stove in my garage for heating, nothing for AC YET.

Any help is appreciated.. any past experiences with this stuff?


Thanks!
Shawn

 

[walrus]

I have a 26x30 garage that I want to insulate, cheaply..

I was thinking of using the 4x8 foam board type (owening corning pink)

I found this stuff for $5 a sheet for the 1.5" thickness. The R rating is "R-7.5".

How much can you get? What if you double up, be R15, not enough for me up here but might work well for you. One thing about foam is it stops air movement so a layer makes fiberglass work better

 

[KongZ TT GT28RS MD]

I can get pretty much as much as I want.. I didn't want to get two layers because of the cost..

I was going to get 1.5" for the walls.. and have different plans on the roof..

Heard of Celotex? Its refletive on both sides.. I found the 1" for $8 a sheet.. but I'm trying to find the R rating of the 1" celotex (reflective) vs. the 1.5" pink owens corning.

 

[headwrench]

i used 1 1/2 thick 4x8 sheets of white styro. i just put it in between the 2x4 girts against the steel siding. im in ohio, and it works fine. sure it could probably be better, but for a detached shop i can live with it. i have worked out there in teen degree weather and have been in tee shirt. the ceiling is also 2 in. thick styro & is also the finished ceiling. i didnt want to hang drywall, tape it, bed it, finish coat it, sand it & then paint it. hang the styro, strip the joints with wood slats & have a beer........done

 

[walrus]

I can get pretty much as much as I want.. I didn't want to get two layers because of the cost..

I was going to get 1.5" for the walls.. and have different plans on the roof..

Heard of Celotex? Its refletive on both sides.. I found the 1" for $8 a sheet.. but I'm trying to find the R rating of the 1" celotex (reflective) vs. the 1.5" pink owens corning.

Celotex is R- 7 per inch. If its all you can afford its certainly better than nothing even if its less than what you think would be ideal.

 

[krooser]

You can run horizontal 2X6's between the posts on 24" centers and use fiberglass batts in between the 2X6's.

I know this would be a little pricier but you'd have it done right and forever.

 

[KongZ TT GT28RS MD]

Update...

At the last second.. I ended up picking some DOW weathermax plus house wrap. Which is what I was planning on pulling across the top (ceiling) of the garage. Pull it tight and then lay insulation across the top of that, in between the joists. The roll type insulation that I can get cheap is R19 owens corning w/out backing. So since it doens't have a moisture barrier, I am planning on using the DOW weathermate plus as that. Plus give a place for the insulation to sit on since it has no backing. Its super thick and very tough. So I am sure I will be able to get it nice and tight. He had it for sale for $55 a roll (9'x150')

However; While I was there the guy mentioned that he had some celotex (Super Tuff R) 4'x8' board insulation. He mentioned it was 1" thick for $8 a sheet. (It was a family owned "home depot" that went out of business). Well, I get there and realize that the insulation is fairly old.. but most still wrapped in plastic wrap. I immediately notice that the boards are definitely NOT 1". I measured and came up with it is 3/4" thick. Some of the edges were messed up and chewed from mice but I don't think it is THAT big of a deal since I will be cutting alot of it anyways. He wanted $8 a sheet (4'x8') and that he cannot go any lower than that.

I told the seller that I was dissapointed that I drove all the way out there and told the other seller (that had the Pink owens corning 1.5" 4'x8' board for $7.50) that I was not coming. The seller then mentioned that maybe I can double it up and get more of an "R" value. I told him that I did not want to afford that and we started to work out numbers. I ended up getting approx 80 boards (some were slightly damaged) for $400 and he sold the roll of the "weathermate plus" house wrap for $50.

So a total of $450 for all that. The "R" rating of the 3/4" is rated at like 5.4.. but if I put the reflective side towards the wall (as I understand) with a 3/4" air space. It will give me an extra 2.8 of R value. Which made the 3/4" celotex have an R-value of 8.2. Which is good for the thickness.

So now I can double up on the walls.. Do you guys think its benificial to give an air space between the doubled up peices on the walls? Like give the 3/4" airspace from the first layer/wall. Then give another 3/4" air space on the 2nd layer that goes on top of the first? Or should I just stack one on the other? Since I'll be doubling up.. Will it give me a cummulative R-value of ~ R-17?



Any help or suggestions would be great!

Also, I found this... anyone try this? Its alot cheaper than other places that I've found.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96328

Thanks again!

Shawn

 

[Dragster Racer]

THanks for the tip on the threshold. I will try one!
YOu never said what you are using the garage for or how you are heating it. My old shop is tough r insulated. I would not want to heat it all the time, but for occational heating, it's fine. If that is what you are planning, stop stressing and just do it. If you want to keep it heated all the time, maybe start with the foam, and cauk all openings so it is tighter than a drum. Another layer with an air gap would be a good addition, or you could bite the bullet at that time and throw batts in there. You could heat it with a candle with the combination. I have a bunch of foam boards I got cheap at an auction, and I am thinking of sticking them between the girts in my new shop, against the metal. Then framing for batts, and osb over that. Blowing in for the ceiling.

 

[gsport]

i think i used exactly what you're talking about on my 45x60 shop.... i too got a great deal on it at an auction and i'm going to have enough left over to sell and probably come out without any cost...