Insulation, Radiant and Vapor Barriers - 22 inch studs

I'm trying to insulate my attic floor (my attic is unfinished) before winter comes (i'm in the northeast - pittsburgh PA) so I'm definitly going to use R-30

my question is - my studs are 22 inches apart, and all the insulation i've found is 16 inches wide....

http://www.lowes.com/lkn?action=productDetail&productId=13566-278-13566

what about the other 6 inches?

can someone point me to some 22 inch wide insulation or advise me on what I do to account for the width difference?

I just picked up mine at Home Depot they carry insulation in 16 & 24 wide, I needed 24 wide. You might call the store and ask them, the web site might not list every item.

i hope you're right...

I just did some quick math - this is going to be very expensive.....

i'm looking at 30' X 30' (14, 22" slots - each 30 feet long...)

is it really worth it ? can i get away with the cheaper R19

(plus i know my neighbor has a bunch of R19 left over from a project I just helped him finish... : )

Wood placed on 24 inch centers would have 22.5 inches between pieces. '24' inch wide insulation would fit. Joists on 16 inch centers are 14.5 inches apart. The insulation should be sized to fit these dimensions.

If there is no insulation, anything would be better. Using R19 instead of R30 will be false economy, because of the incremental cost to make up the difference later. You could use however much of the R19 to start and layer over it with enough additional to make the R30.

Hope this helps.

Just ask for 24" insulation .it will fit there in you 22.5 thats just 24" on center. Use what the other guy has left over of the R 19 then get some more R-19 for the job . Then----- They now have what is called Attic blanket with a R-25 Run this the other way across the joist put this on top of the other. Make sure the paper side on the first insulation is down to the room. This will give you a R 44 there and I think up there they say put in a R40 so you got it made ;) ED

So I went to go get my insulation....and I was in tears when it came time to buy it...

realizing that there was just no way I could afford to buy all the insulation i needed, I decided to go another route...

buying the batts (r-30) was going to cost around $650 for the whole job...

after discussing my options with the folks at lowes, and a few experienced friends i brought along, I decided to go with the blow in fiberglass... this lowered my costs to $200 and I acttually got a few extra bags. (there was a $50 mail in rebate if you spent $200 on insulation) plus i opened a lowes credit account and got an additional 10% off...so I saved some serious money....

But am I naive for getting the blown-in kind? I mean why would it be so much cheaper unless there was some sort of draw back? Or is it cheaper because it's harder to work with??

Don't forget the vapor barrier.

The loose material is cheaper because the packing costs are lower. No batts. Just bags. It is messier to work with.

You could put an R13 paper side down first then a blow on top of it. lowes also has the Cellulose insulation with the blower to use it. Lots better than fiberglass wont burn at all in a fire and fiberglass will melt and let a fire on through. Like chfite said its all in the packing cost;) ED

where do i put the vapor barrier?


I have exposed floor studs in my attic, and I was planning on blowing between the studs and the putting plywood over when i was finished so i could store stouff up there without disturbing the insulation.... (of course i plan to use a ton of "Great Stuff" to fill in all of my gaps, and make moats around my exposed electrical fixtures in the attic "Floor" - as explained in the manufacuters instructions)

do I put the vapo barrier on top of the insulation and then put ply wood over that? or do i put the VB on top of the attic "floor" and then blow insulation on top of it?

The V/B or paper side goes down to the room ceiling below. Then blow on top of it;) ED

well I already bought the Fiber glass, so I think I'll stick with that.

As far as the Vapor barrier -

Ed - you said -
You could put an R13 paper side down first then a blow on top of it.

you mean buy R13 batts and roll them down upside down (paper down) adn the blow on top of that....?

what else could i use as a vabor barrier?

You could cut like a 2 or 4 mil poly film to fit and put it down in the rafters first then blow insulation on top of it. Ask at Home depot or Lowes there is a paint that you could put on the ceiling that works as an V/B also.Or the paper batts paper side down and blow on top of that.;) ED

so i can just use that plastic that you buy in rolls...like what I would use to cover my windows in the winter?

SURE CAN ;) ED

should i staple it down?

ps - sorry for all the newbie questions.... : )

I thing I would some just cause it would try and blow around on you when you start the blow in insulation thats all;) ED

thanks a million ed, and everyone else...

I'll let you all know how it goes

dont forget the rafter vents as they call them .So the air can get up from the vents in the over hang and all this new insulation dont block the air there.;) ED

baffels?