Ceiling Insulation question

[airwalk]

So I'm currently building my new garage (32x40 3 car detached) from a custom package put together by the local Totem store, and after some discussion with my dad about blown-in ceiling insulation I thought I'd double-check my bill of materials. Sure enough, they set me up with fibreglass bat insulation for the ceiling.
I'm looking for some opinions on what is better to use, blown-in insulation or just regular bats (the fibreglass is R40, not sure of the other). I was planning on using the blown-in as that is all I've ever seen in both my last house and my current house, as well as my dad's brand new cabin at the lake, but since I've already paid for the bats I want to make sure it's worth the effort to get a refund.

Sorry if this is the wrong location for this thread, and thanks in advance.

 

[Doug B]

Fiberglass is good insulation. Just pay attention to the details when installing it. In trusses,I like to install 3 or 4 batts,then go up above and 'adjust' them. Make sure the **** joints are tight,fluff up the corners that get folded over from pushing up into the truss bay, etc. Remember,its the loft that gives it the r-value.

 

[ddawg16]

Sorry if this is the wrong location for this thread, and thanks in advance.

Can't think of a better place to put it (post that is)....so your good....

As for the insulation....it's my understanding that batts provide longer insulating value as well as including a built in vapor barrier....over time, blown in settles and ends up being a fraction of it's original R-value....not to mention being a real PIA to deal with.

On my house (built in 52), all of the blown-in insulation had settled to the point to where it was only about 1-2" high....I made a 'push' (long stick with a 10"x 4" piece of plywood on the end) so that I could push all of the insulation out towards the perimiter. I then installed 6" and 8" batts in the open space....made a big difference...

 

[tfi racing]

Unless you are using the attic for storage,blown in is best for your part of the world,there are just too many gaps in using batts for the ceiling.You likely want the maximum recommended depth,when its -35 later this winter you need all the help you can get with that ridiculous Alberta gas bill!

 

[airwalk]

Unless you are using the attic for storage,blown in is best for your part of the world,there are just too many gaps in using batts for the ceiling.You likely want the maximum recommended depth,when its -35 later this winter you need all the help you can get with that ridiculous Alberta gas bill!

I'm in Saskatchewan, and gas is reasonable ($5.21/GJ), but that doesn't mean I want to buy a whole lot of it, cause it does get COLD here pretty soon.

Thanks for the info, I'll consider it all. While we (my dad and I) were working out there today we were talking about this again and his suggestion was blown in fills all the voids (electrical wiring, under truss bracing, over lower truss member itself, etc.) where batts will be tricky to properly install without having gaps.

By the way, does anyone know the R value of blown-in? Obviously it depends on the depth, so as well what's a typical depth?

I've heard that too ddawg, about settling, but your house is 50+ years old so I imagine batts would not look the same after that much time either.

 

[PurdueSD]

I would stay away from cellulose in a garage anyways. Too much humidity and temp swings. IMO.

 

[Ezzie]

For the Canadian winters, my preference is to spray the ceiling from above with 1" - 2" of closed cell urethane foam and then use blown cellulose on top - about 18" to give a good solid R50-R60. With the foam application, it gives the ceiling an air tight seal around all lighting fixtures, stacks, etc. and you don't need a vapour barrier. The foam is about $2/sq. ft, the cellulose about $1/sq. ft.

 

[airwalk]

I would stay away from cellulose in a garage anyways. Too much humidity and temp swings. IMO.

I assume the humidity would be from gas heat? You are right about temp swings, I hope to keep it just above freezing except when I'm working in there. How much effect does this really have on cellulose?

For the Canadian winters, my preference is to spray the ceiling from above with 1" - 2" of closed cell urethane foam and then use blown cellulose on top - about 18" to give a good solid R50-R60. With the foam application, it gives the ceiling an air tight seal around all lighting fixtures, stacks, etc. and you don't need a vapour barrier. The foam is about $2/sq. ft, the cellulose about $1/sq. ft.

That's a good idea Ezzie, but it would be ugly if you wanted to change a lighting scheme or add an outlet in the future. I guess it could be done though.