Attic insulation.

[mrsilv04]

Currently, I have somewhere around R-19 in my attic. And in Illinois, that isn't enough. It is blown-in fiberglass insulation.

I want to double that to R-38. Right now, I see two options.

1) Blow in another 8 inches of loose fiberglass.
2) Roll out a layer of R-19 (6.5") across the tops of the rafters. The current blow in is about 8" thick, so it may get compacted a little by the installation of roll insulation.

Right now, I'm leaning towards the rolls. Mainly since it will be a lot cleaner to install, and that I could do 4-5 rolls (or until my back starts hurting) each night after work, and then have the project easily finished within a week.

Blow-in would have to be done all at once, plus the renting and returning of the machine... and it will cost about 50% more.

And the R-19 just happens to be on sale for $7.99 a roll (15" x 39' or 48 sq. ft)...

 

[BISCUT]

I have R30 in my attic and cross patterned rolls of R19 and it made a difference in the heating bill (oil heat). Calculated out to about 5 years break even point with the cost of insulation. I'd go with the rolled, unfaced myself. Blower is a hastle!!

 

[mrsilv04]

UPDATE:

Just noticed that the blow-in insulation will be on sale this weekend, and there is NO price difference between roll out or blow in anymore... unless there is a charge to rent the blower.

 

[bepperb]

Can you isolate the area the blower will be in to control dust? I'd rather blow, the problem is the cleanup afterward.

 

[Donald]

A guy I know who is involved in NY energy audits, etc says he likes cellulose as it does a good job and mice hate it.

I would go with the rolls or batts. You want to make sure the blown in does not cover any sofit vents.

 

[mrsilv04]

Originally Posted By: bepperb
Can you isolate the area the blower will be in to control dust? I'd rather blow, the problem is the cleanup afterward.


My attic access is in my garage. Weather permitting, I could put the blower out on the driveway, and close the overhead door down to the point where it is touching the hose, and then go in and out to load it through the walk-in door.

 

[R80RS]

I'd pick unfaced rolls over more blown if it was me.

And whatever you decide, don't overlook the potential impact of adding more insulation on attic venting, particularly the soffit venting. Add "proper vents" before insulating to keep the soffit intakes open.

 

[InhalingBullets]

I know here in Texas at Home Depot if you buy more than 10 bags of insulation the rental of the machine is free.

 

[Oldmoparguy1]

I recommend cellulose, unfaced fiberglass allows air movement. Blown Cellulose is nearly air tight. The realized R-value is greater then loose fiberglass. I've re-insulated 2 houses, including sidewalls myself. My current house has 6" blown on top of existing fiberglass.

Wayne

 

[JTK]

Originally Posted By: R80RS

And whatever you decide, don't overlook the potential impact of adding more insulation on attic venting, particularly the soffit venting. Add "proper vents" before insulating to keep the soffit intakes open.


Yep, that's more important than anything IMO. You want free-flowing outside air up there.

Thankfully, my home has those foam air baffles between every roof joist and my soffets are vented. Someone went nuts with the blown-in at some point. They had to build a riser through the ceiling access opening it's poured so deep up there! Only thing I dread is, it buries all your wiring and my 2 upstairs bathroom exhaust fans and associated duct work are buried in the stuff. Both fans are ducted together and I'd love to sort that out.. Ugh.