Faced or Unfaced Insulation in Attic???

capenpeck · 01-03-2009, 01:14 PM

Hi,
Forgive my ignorance, but I am lost on if I should install faced or unfaced insulation in my attic. I have read different opinions all over the internet.

I live in Southeastern Pennsylvania and my house is about 30 years old. Currently, there is R19 unfaced insulation up there. I want to insulate the attic and then put floorboards up there for storage.

Could someone please let me know if I should use faced or unfaced insulation and what direction it should face.

Thanks for helping a newbie.

kbsparky · 01-03-2009, 01:58 PM

Facing on insulation batts is intended to act as a vapor barrier.

If you are adding to an existing insulated ceiling, make sure that there is not a vapor barrier already present. There was a time when plastic sheets were installed to act in this capacity. You don't want more than one vapor barrier up there, or else you could end up trapping moisture, and that won't be good.

IF there is no vapor barrier present, then you could install faced insulation if desired. Any existing insulation should be removed first, and the facing installed against the ceiling towards the living space. Then you can add more unfaced insulation on top of that if you wanted to increase the R-value.

capenpeck · 01-09-2009, 08:57 AM

Thanks kbsparky! Appreciate all of the help!

TotalRecall · 01-17-2009, 05:18 AM

Is there a problem with not having a vapor barrier for insulating the attic? I always heard not to have a vapor barrier for the attic floor, but I see Home Depot and Lowe's are going to a vapor barrier R-30 & R-38 batts. Does it make a difference if plywood is above the floor joist?

vsheetz · 01-17-2009, 05:29 AM

Have you considered blowing in loose fill insulation? Buy the insulation from them and many place with loan you the blower machine. I've done it a couple times to add to existing attic insulation - depending on your attic, much easier and I think better than trying to lay insulation blankets.

diy4me · 11-05-2009, 10:05 AM

Right now i have bare walls and attic. Looking at the R-30 for my attic. Should I go faced or unfaced?

Does it make any difference? If I buy faced I just have to face the paper towards the ceiling part.

ArmchairDIY · 11-05-2009, 12:13 PM

If your insulating over existing insulation use unfaced. better yet as mentioned use blown in insulation it's less expensive and fills gaps and void more effectively.
The vapor barrier always is install toward the warm side (inside) of the building.

ccarlisle · 11-05-2009, 12:46 PM

DIY4me, it all depends on the vapour barrier you already have, if you have one (if you're looking at R30 insulation, I reckon you're in the mid-US somewhere, ie. half in-between Mexico and Canada)...so you should go up there are see.

It could be just a good layer of paint on the ceilings below, or it could be a plastic sheet just below the joists, or faced batts. But it should be on the warm side of it all.

diy4me · 11-05-2009, 02:57 PM

Quote:

Originally Posted by ccarlisle

DIY4me, it all depends on the vapour barrier you already have, if you have one (if you're looking at R30 insulation, I reckon you're in the mid-US somewhere, ie. half in-between Mexico and Canada)...so you should go up there are see.

It could be just a good layer of paint on the ceilings below, or it could be a plastic sheet just below the joists, or faced batts. But it should be on the warm side of it all.

I'm in Northern Massachusetts. Right now there is no insulation at all. I have ripped the walls and ceilings. In my walls I have put faced R-13.

I wanted to put insulation in the attic before doing the sheetrock. I have gotten mixed answers i.e unfaced or faced.

That's why I was wondering which one to use.

**Gary in WA** · 11-05-2009, 03:10 PM

Capen, I would run unfaced perpendicular to the joists with the R-19 (if the joists are 2x6) already installed there. If you blow-in cellulose it will compress the fiberglass already there and lose some R-value. This is because loose cellulose weighs .14# per square foot- per inch of thickness, 3-1/2 times more than glass batt. Adding 8" of cellulose would be adding +1# (a pound package of butter's weight) to every square foot of glass batt. Yet the glass weighs only .04# or 1/4 pound-6" thick. If using blow-in, fiberglass loose fill weighs the same as batt, but doesn't have the air-sealing qualities as cellulose does.

Latex primer sealer paint is 1/3 as good for stopping vapor transmission as oil primer and one coat. Latex primer sealer is 1/12 as good as a vapor retarder specified primer paint. Proper attic venting and air sealing the ceiling is critical to condensation and frost in the attic, and ice dams on the roof.
Be safe, Gary

ccarlisle · 11-05-2009, 03:36 PM

OK well then you're a bit farther north than I thought...LOL

See up here we'd put up a vapour barrier on the inside of the ceiling, stapled to the joists, then put up the drywall over that. Then, up in the attic, we'd blow insulation between every joist up to R50. Now if we were using batts, we'd put unfaced batts between the joists then run another layer perpendicular to the joist to get as high and R-value as we could. Both unfaced - because the vb is already there...

But in your case you'll need a vapour retarder of some sort..the facing of the faced batts provides some, so put those facing down between each joist then run another layer perpendicular to the joists on top.

But one thing is certain: we both have greater problems with air movement than we do with levels of insulation. That's why we go with an airtight vapour barrier rather than mess around with leaky paints or batt facing. So we seal the house up tight from the inside, and on the walls as much as we worry about how many inches of insulation we have because in our climate, air movement is the major cause of heat loss.

Thurman · 11-05-2009, 08:44 PM

My electrical supply comes from Georgia Power Co. They offer free home energy audits. I had my house audited about three (3) years ago and one of the interesting items the auditor told me was that IF I decided to add any insulation to my attic, which is adequately insulated, to be sure to run the new 4"-6" unfaced insulation perpendicular to the rafters, just as GBR stated. The auditor told me that this method would entrap some air between the two layers of insulation which would act as additional insulation. Another note was that placing any type of flooring on the additional insulation would lower it's rated R-value by it being compressed. Good Luck, David

diy4me · 11-05-2009, 09:47 PM

Quote:

Originally Posted by ccarlisle

OK well then you're a bit farther north than I thought...LOL

See up here we'd put up a vapour barrier on the inside of the ceiling, stapled to the joists, then put up the drywall over that. Then, up in the attic, we'd blow insulation between every joist up to R50. Now if we were using batts, we'd put unfaced batts between the joists then run another layer perpendicular to the joist to get as high and R-value as we could. Both unfaced - because the vb is already there...

But in your case you'll need a vapour retarder of some sort..the facing of the faced batts provides some, so put those facing down between each joist then run another layer perpendicular to the joists on top.

But one thing is certain: we both have greater problems with air movement than we do with levels of insulation. That's why we go with an airtight vapour barrier rather than mess around with leaky paints or batt facing. So we seal the house up tight from the inside, and on the walls as much as we worry about how many inches of insulation we have because in our climate, air movement is the major cause of heat loss.

I'm getting the R-30 faced from Lowes and will install it with the paper facing down. Then I will take whatever if left from my unfaced R-19 and put it on top.

ccarlisle · 11-06-2009, 08:23 AM

Sounds like a plan to me...

I mentioned paints: some paint coverings can act as a vapour retarders too, probably in warmer climates - but in most climates, it's better than nothing. I maintain that nowadays we ought to worry more about air leakage than insulation levels, as up here as well as down south, you need to keep the permeation of air through the outside walls to a minimum. Leaky houses used to be part of the architecture, but now we know more about the energy costs of those leaks and it is often more than the savings in more insulation levels...