Attic insulation - Contractor Talk - Professional Construction and Remodeling Forum

Rennovator · 10-27-2009, 02:31 PM

Which one should I use Kraft faced or unfaced for attic insulation. Looking to use 24" R-30.

From what I have heard in the past a moisture barrier isn't necessary for the attic. So before I go out and buy a ton of insulation, I wanted to as you insulation pros on here. Thanks

**genecarp** · 10-27-2009, 02:40 PM

REN, please complete your profile, tell us a little about your business, and how long you have been in construction, thanks GMOD

Rennovator · 10-27-2009, 02:55 PM

Quote:

Originally Posted by genecarp

REN, please complete your profile, tell us a little about your business, and how long you have been in construction, thanks GMOD

Have been doing some jobs here and there, mainly flooring, tiling. Decided to earn some $$ doing it. I'm looking to gain some knowledge in window installation, insulation and hopefully plumbing.

Mostly did some rennovation jobs with flooring and tiling.

**genecarp** · 10-27-2009, 02:56 PM

Quote:

Originally Posted by Rennovator

Have been doing some jobs here and there, mainly flooring, tiling. Decided to earn some $$ doing it. I'm looking to gain some knowledge in window installation, insulation and hopefully plumbing.

Mostly did some rennovation jobs with flooring and tiling.

Thanks , REN

parts · 10-27-2009, 06:08 PM

Unfaced if there is exiting. Is it a truss ceilin hauling bags though that is difficult I won't even price batts only blow

Rennovator · 10-27-2009, 06:23 PM

Right now it's bare. I was told that it's it's kraft faced to lay if facing down but unfaced was better.

Does it make any difference? Do I still have to put a moisture barrier like 6 mil plastic to cover the ceiling prior to sheetrocking?

Lefty H · 10-31-2009, 12:25 PM

Hi,

Use faced insulation.

Rennovator · 11-04-2009, 09:54 PM

Quote:

Originally Posted by Lefty H

Hi,

Use faced insulation.

Any reason why you prefer faced insulation for attic (kraft side faces down) ?

Mike Finley · 11-04-2009, 10:34 PM

Why wouldn't you blow insulation instead? Batts are pretty much useless in my opinion.

If you are going to use batts put the Kraft side down. Vapor barrier goes on the warm surface. But don't sandwich any kraft paper between layers, peal those off after the 1st layer.

Or just blow loose fill insulation in.

WarnerConstInc. · 11-04-2009, 11:29 PM

I heard Rock Wool is all the rage.

Vermiculite is starting to catch on though.

Rennovator · 11-05-2009, 08:55 AM

Quote:

Originally Posted by Mike Finley

Why wouldn't you blow insulation instead? Batts are pretty much useless in my opinion.

If you are going to use batts put the Kraft side down. Vapor barrier goes on the warm surface. But don't sandwich any kraft paper between layers, peal those off after the 1st layer.

Or just blow loose fill insulation in.

Blown insulation is coming up over the budget. Why would you say batts are useless?

I was deciding versus this :

http://www.lowes.com/lowes/lkn?actio...344&lpage=none

OR

http://www.lowes.com/lowes/lkn?actio...243&lpage=none

Problem is that no lowes close to me seem to carry the unfaced R-30 which is very strange. I have to special order them. Since I keep hearing from some local insulation guys that unfaced is preferred for attics and that the unfaced batts cost about $9 less per package. That why I asked what makes sense faced or unfaced.

mics_54 · 11-05-2009, 10:06 AM

The only advantage friction fit batts have over blown in cellulose is batts can be installed from below prior to drywall. You can insulate that way in cold weather then put up a VB and get some heat in the building to drywall. Last I checked blown in cellulose installed was cheaper than equivelent R value batts installed. I recommend an R38 in the ceiling.

Rennovator · 11-05-2009, 10:21 AM

Quote:

Originally Posted by mics_54

The only advantage friction fit batts have over blown in cellulose is batts can be installed from below prior to drywall. You can insulate that way in cold weather then put up a VB and get some heat in the building to drywall. Last I checked blown in cellulose installed was cheaper than equivelent R value batts installed. I recommend an R38 in the ceiling.

Yes i was hoping to install the insulation prior to the drywall. The quote I got for blown in R-30 value was about $500 more than just buying the batts and doing it. Got 3 quotes about the same.

I have a lot of R-19 unfaced left over that I was thinking of putting on top of the R-30. That would give me about 18 inches total.

But the question is whether i sohuld g faced or unfaced on the R-30.

neolitic · 11-05-2009, 10:34 AM

Quote:

Originally Posted by Rennovator

Yes i was hoping to install the insulation prior to the drywall. The quote I got for blown in R-30 value was about $500 more than just buying the batts and doing it. Got 3 quotes about the same.

I have a lot of R-19 unfaced left over that I was thinking of putting on top of the R-30. That would give me about 18 inches total.

But the question is whether i sohuld g faced or unfaced on the R-30.

If the attic is ventilated use unfaced.
Get the 24" friction fit.
Your climate is similar to mine.
A vapor barrier isn't necessary in a
ventilated attic.

mics_54 · 11-05-2009, 10:55 AM

Quote:

A vapor barrier isn't necessary in a
ventilated attic.

In what way is a vapor barrier not necessary and in what instance would an unventilated attic be appropriate with an insulated ceiling below?

neolitic · 11-05-2009, 11:10 AM

Quote:

Originally Posted by mics_54

In what way is a vapor barrier not necessary and in what instance would an unventilated attic be appropriate with an insulated ceiling below?

We are not all in Alaska.
It may be required there, it isn't here.
The idea is water vapor passes through
the ceiling and is vented from the attic.

mics_54 · 11-05-2009, 11:52 AM

OH! you meant REQUIRED...I thought you meant necessary.

The problem with that theory is the means by which water vapor passes through the ceiling...the majority of which is carried with warm air. This means heat loss. Do you like heat loss? I don't like it. It's expensive to heat air. I want to keep it in the space below the ceiling rather than vent it out of the roof attic into the atmosphere. I know you agree.

neolitic · 11-05-2009, 12:25 PM

Quote:

Originally Posted by mics_54

OH! you meant REQUIRED...I thought you meant necessary.

The problem with that theory is the means by which water vapor passes through the ceiling...the majority of which is carried with warm air. This means heat loss. Do you like heat loss? I don't like it. It's expensive to heat air. I want to keep it in the space below the ceiling rather than vent it out of the roof attic into the atmosphere. I know you agree.

It isn't necessary.
Not here.
Water vapor travels from the higher
concentration to the lower concentration.
It does not require heat transfer.
There is no difference in heat loss whether
there is R-38 with vapor retardant, or R-38
with out vapor retardant.

Mike Finley · 11-05-2009, 07:08 PM

Quote:

Originally Posted by Rennovator

Yes i was hoping to install the insulation prior to the drywall. The quote I got for blown in R-30 value was about $500 more than just buying the batts and doing it. Got 3 quotes about the same.

Is this for your house or a customer. I was under the impression this was a job you were doing for somebody.

I thought you were going to do the work?

Quote:

Originally Posted by Rennovator

I have a lot of R-19 unfaced left over that I was thinking of putting on top of the R-30. That would give me about 18 inches total.

But the question is whether i sohuld g faced or unfaced on the R-30.

How many times you gotta be told my boy?

Faced insulation agaist the drywall ceiling. The craft paper goes against the warm surface. If you put more on top of the first layer, it goes on at 90 degrees to the bottom layer and make sure you don't have any paper sandwiched between them.

If I have to tell this all again I'm going to send you a bill.

Hey, has anybody told you, blown in would be a lot better way to go?

Rennovator · 11-05-2009, 09:41 PM

Quote:

Faced insulation agaist the drywall ceiling. The craft paper goes against the warm surface. If you put more on top of the first layer, it goes on at 90 degrees to the bottom layer and make sure you don't have any paper sandwiched between them.

If I have to tell this all again I'm going to send you a bill.

Hey, has anybody told you, blown in would be a lot better way to go?

Ok im getting the faced R-30 with the paper facing the floor

from Lowes