Insulation - please comment

[Fun pain]

I attached a screen shot of buildingscience.com on natural convection and loop..and imagine that these are NOT enclosed but open at the top. There isn't a loop, heated air just raises out of the wall.

All insulation is trying to slow this process (loop/convection) down.... A ceiling is resisting heat transfer vertically, natural convection is working vertically because gravity....

Walls and gravity act at 90degrees from that.....

Hot air rising doesn't work left to right in a ceiling

 

[Highbeam]

I attached a screen shot of buildingscience.com on natural convection and loop..and imagine that these are NOT enclosed but open at the top. There isn't a loop, heated air just raises out of the wall.

All insulation is trying to slow this process (loop/convection) down.... A ceiling is resisting heat transfer vertically, natural convection is working vertically because gravity....

Walls and gravity act at 90degrees from that.....

Hot air rising doesn't work left to right in a ceiling

Nice picture but it proves the point that an air gap behind the batts is just fine. To cause a convection loop you need to somehow provide connected gaps on all sides of the batts. Properly fitted on 5 of the six sides, batts will not create this problem.

 

[theoldwizard1]

... you might like how I do it... easier, cheaper, faster, better (then most ways)

http://www.garagejournal.com/forum/showthread.php?t=228691

step 1; seal the wall from ground moisture. (foundation coating works)
step 2; just put 4' on center girts on the inside *
step 3; staple up webbing
step 4; fill wall with cellulose

* Looking back at your posts, I would say a better description would be that the girts were installed "horizontally, between the post".

The more I think about your method, the more I like it !!

The small amount of work up front, (installing the webbing), pays off big with simplicity and cost savings of blown in cellulose !

Fun_pain - Do you recommend vapor barrier or house wrap between the cellulose and the tin ? What you you think of spray foaming just between the top and bottom plates on the tin ?

 

[Fun pain]

House wrap would be most cost effective. That would both serve as a drainage plain and SEAL.That would help greatly without causing moisture problems It will breath in one direction, make sure that it is NOT a Vapor Barrier Style housewrap. And try to tape the seams the best you can...

Spray Foam is pretty great, Just very expensive... closed cell foam is almost always a vapor barrier, and open cell is not.


Highbeam.... I agree 5 side won't allow a loop....thats my point... it will just raise up, and out of the insulation and up the air gap. Be it, yes it will be slowed by the fiberglass but 6 sides would almost stop that and create a loop. The better the fiberglass or whatever fills the 6 sided box the closer this loop effect comes to a stop.

 

[Fun pain]

https://scontent-b-ord.**.fbcdn.net/hphotos-prn2/1526922_10202965671731703_514961179_n.jpg

 

[jack stand]

http://www.insulationdepot.com/
Check these guys out to see if they have anything in your area. I used their p-iso 1.5" panels against the steel siding (tyvek under the steel) in between the wall girts, foamed ALL the edges, then ran another layer vertically, also foamed in place. This leaves room for r-13 fg if you build a wall in between your posts. Makes interior finishing easy too.
The 4x8x1.5" sheets were about $7 each 5 years ago. The material is used, commercial roof take offs and in good shape. The kicker is you need to buy a trailer load if you want it delivered. I was able to pick it up and negotiated a deal on what I needed.

 

[Rick98Z]

I went with framing in my pole barn. I stapled tyvek in between the posts before framing to the wall girts so the insulation wouldn't touch the metal siding incase of moisture issues. I intermixed 2x4's and 2x6's and nailed the 2x6's into the wall girts for extra strength. Insulated with r19 paper-faced rolls and then drywalled. Ceiling trusses are 4' o/c so I am going to put vapor barrier up stapled to bottom of trusses and then install metal ceiling with blown insulation. I also went along the inside bottom of the exterior metal with non-expanding spray can foam to seal the ribs of the metal at the rat guard.

Not saying this is the best way to go, just seemed cost effective for me at the time. My garage is a 40'x60' and I sectioned it out into 40'x40' three bay garage with two 20'x20' rooms. Rooms are going to have a heat pump giving hot/cold and I am going to probably run an extra duct into garage bay to help with some residual air flow. Doubt it will give a whole lotta heat to the 40x40 section but probably going with a propane radiant hanging heat tube later for there. One big thing is garage door air loss it seems, the better you can seal around them, the better you will be in the long run!

 

[JTB]

Thanks for all the info guys, been and gone and done it now, just ordered the foam, insulation, studs, Dura-Panels, lights, scaffold from Menards.......now to install it!!

Cheers, John

 

[Fun pain]

Have fun and post often...