Blown Insulation- R Value?

[NRChopshop]

I am at the point where my next step is to start dry walling my garage ceiling. So i need to start thinking about insulation also. So far in researching blown-in insulation, i can't seem to find out what R-values corresponds with what amount of insulation im putting in. My building has 24"OC, 2x4 trusses and i plan to use the attic space for storage, so i can't pile the place with 10" of the **** like ive been reading, others have done.

Level with the 2x4s, what kind of retention of heat am i looking at? My walls have R-13 and im looking obviously for something much more substantial for the ceiling.

 

[TRDon]

go to your local supplier and read the bags. They will tell you what the R value per inch on insul will equate to.

 

[Kinger]

Most blown in insualtion equates to about an R=3.5 per inch.

You will be better off doing (slightly) by doing r-13 batt in your joists.

Is your whole attic going to be storage? If not, you could wall off around your storage and add blown in around the storage area.

 

[NRChopshop]

The problem with using the batts is the 24" truss spacing. finding insulation in the width around here is tough unless the studs are 6". I dont want to wall off any of my attic. Dont want to spend or do any more work than i have to.

 

[Sundowner]

I've seen R-15 for 3.5" thick batts, and if you've got the bucks, the closed cell spray-in foam insulation gets (I think) R-6/inch.nice thing about the closed cell is that you can over-fill it past the 2x4's if you want.

 

[BlueZero]

I've seen R-15 for 3.5" thick batts, and if you've got the bucks, the closed cell spray-in foam insulation gets (I think) R-6/inch.nice thing about the closed cell is that you can over-fill it past the 2x4's if you want.

I agreed! Look in to the closed cell spray foam.

 

[Dragster Racer]

Um. He said he doesn't want to spend any more than he has to. Spray in would tend to be out then. Not sure why the trouble getting 2' batts. The lumber yard I use and Menards both have 23" batts in stock all the time unfaced. Quick and easy to do that way. That is what I am doing, but I am using osb. You will have to watch yourself with 2' centers so that you never step on the drywall. Not sure if it supports itself ok with that wide of centers without sagging. You will want a vapor barrier also. If you are heating this full time, you will kick yourself for not using more insulation. If only heating when you use it, that won't be an issue.

 

[NRChopshop]

The building is only heated when i am in there. We dont have Menards here. Actually until i got on this forum I had never even heard of it. Neither Home Depot or Lowes has 24"wide batts in anything less than 6" deep. Im not really even sure where else to look for it. There will be plywood put down in the areas open enough to for storage which is the main reason i dont want any insulation deeper than 4". I dont have a ton of money to play but still want to do the best i can with what i can afford to do

 

[Joe Reed]

You could just use the batts for 16" OC and cut half of them lengthwise & use those pieces to fill the gap. Lotta work, but.....

 

[GSSFC]

It is kinda pricy, but you could buy 4" rigid foam board and install that. You'd get two rips out of a sheet with a couple inches of waste. You won't get better than R-13 out of a 2x4 cavity with fiberglass. Call your lumber yard, you can get 24" wide fiberglass R-13. It is what is used in 24" oc walls. It is readily available.

Tim

 

[s_ontario]

I just added some Cellulose insulation into my ceiling been 20 years since I first did it and had some settling so now i have 7"

5.9" = R value of 20
8.3" = R value of 28

Reading off the bag for machine blown in ceilings
3.5" = R12 value and is equalto 3.2 settled inchs lb/ft.square .42
coverage / 25# bag 5.5 square m or 59.3 sq foot ?

my walls are 2x6 stud filled with blown in Cellulose also
2x6 walls = R value of 20.2
2x4 walls = R value of 12.6

 

[2LTim]

NRChopshop:
Try looking in the yellow pages under "Insulation Contractors." You may get lucky and find someone with something he wants to clear out at a good price since it's not that popular any more.
Tim

 

[chaingang]

Why not just use the 6 inch material and compress it in the areas of the plywood floor. It isn't going to hurt the R value much and you said you only heat it when you are in there anyway. You can get R15 in 3 1/2 bats but not sure if you can get it 23 wide. Maybe even R19 in 3 1/2.