kraft paper backed or non backed insulation

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  #1  
Old 04-03-13, 06:15 PM
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kraft paper backed or non backed insulation

Hi all.

I need to insulate a small space in a ceiling over kitchen. (9x9).
There is no existing insulation. (no ceiling either at this point)

House is in South Florida.

My understanding has always been that you don't need vapor barriers in S. Florida. I don't know why or where I got this reasoning or if it's true. Just what my brain thinks.

So, should I use kraft paper backed R30 or just the unbacked insulation?
Or, something else.

And, if paper backed, is the paper side up or down? And, is the paper allowed near recessed lighting?

Thanks
Tim
 
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  #2  
Old 04-03-13, 06:54 PM
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Hi Tim,
The general rule is the vapor barrier (or better referred to as vapor retarder) goes on the warm side. So if your home is air conditioned then the kraft would go to the outside. Now, here's the exception/s. Since most moisture is carried via air leaks, just seal the leaks and forget the vapor retarder. In either case, kraft backing stabled carefully into place is still a poor VB, so where you put it is not all that important. It is important to have the insulation in contact with a rigid air barrier, like drywall.

I can dig out the references if needed.
Bud
 
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Old 04-03-13, 06:56 PM
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Whatcha gonna do with the moisture that is created between your relatively cool house and hell's kitchen in your attic??? Yes, use a vapor barrier, face down between the joists, paper toward living space. Your recessed lighting will depend on whether the fixtures are IC or non-IC cans. If they are insulation contact type, you can cut a hole and place the insulation right over the fixture. non-IC cannot have insulation contacting or around the fixture to where it will block the flow of air.
 
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Old 04-04-13, 03:24 AM
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I used to work in central fla Back in the 80's while a vapor barrier wasn't always used on the ceiling, it was mandatory for walls!

Some recessed lights can't touch insulation or they will overheat. I don't know which lights can but I'm sure the others can help you determine which type you have.
 
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Old 04-04-13, 09:29 AM
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The recessed housings that can be in contact with insulation are rated IC, for Insulation Compatible. That will be marked on the fixture. Because these lights are penetrating the plane between the conditioned space and the unconditioned attic, they must also be rated AT (Air Tight). That will also be marked on the fixture.
 
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Old 04-04-13, 11:40 AM
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"In hot climates and during cooling periods the opposite is true. Building
assemblies need to be protected from getting wet from the exterior,
and allowed to dry towards the interior. Accordingly, air barriers and
vapor retarders are installed on the exterior of building assemblies, and
building assemblies are allowed to dry towards the interior by using permeable interior wall finishes, installing cavity insulations without
vapor retarders (unfaced fiberglass batts) and avoiding interior “nonbreathable”
wall coverings such as vinyl wallpaper."
From; http://www.buildingscience.com/docum...apor-retarders

Not required for your location, ceiling or walls; Info-310: Vapor Control Layer Recommendations — Building Science Information

Gary
 
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Old 04-04-13, 03:27 PM
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Home Depot says on their website:
"Generally, in hot, humid areas, using a vapor retarder is not recommended."

This seems strange to me in that I can't find any 24" R30 unfaced at their stores locally. Most everything is faced. I guess upper management is the same quality as the floor staff.
 
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Old 04-04-13, 03:52 PM
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Our local Lowes carries R30 unfaced. If your stores don't stock it, maybe they will order it for you.
Would blown insulation be a viable option? maybe up grade the rest of the attic at the same time ??
 
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Old 04-04-13, 04:37 PM
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That's an idea Marksr.
I've done the blown in cellulose before. Fun stuff......um....
When I did it, I tied the hose to a long pole. worked out pretty good.
In this house, I'm concerned about the recessed lights (non IC).
Don't know how to deal with them. ANy ideas?

Yea, my lowes doesn't have anything either. Guess I'll have to order it.

Here's a pic of the ceiling if anyone's interested
 
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Old 04-04-13, 04:40 PM
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It would probably be a good idea to replace those can lights with ones that are IC rated .... or a different type of light.
 
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Old 04-04-13, 08:10 PM
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In this house, I'm concerned about the recessed lights (non IC).
Don't know how to deal with them. Any ideas?
Yes. Replace them. This is the ideal time, because you've got the ceiling open and can use the less expensive new construction housings and run the wire wherever you need it.
Originally Posted by Nashkat1
The recessed housings that can be in contact with insulation are rated IC, for Insulation Compatible. That will be marked on the fixture. Because these lights are penetrating the plane between the conditioned space and the unconditioned attic, they must also be rated AT (Air Tight). That will also be marked on the fixture.
Then air seal the ceiling as you replace it. Those two improvements - the sealed light fixtures and air sealing the ceiling - may do as much as new insulation will.

Or, as Mark suggested, you could change to surface-mounted or pendant light fixtures.
 
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Old 04-05-13, 03:59 AM
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Was this a trey ceiling at first? I am confused by your sheetrock ending above the cabinets, spaghetti all through the ceiling and can lights at a different level. Was it a grid ceiling?
 
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Old 04-05-13, 05:20 AM
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chandler. It used to be this:
 
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Old 04-05-13, 08:53 AM
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It appears that the recessed fixtures were never in the ceiling joists. I think that may be your answer. Install boxes to feed track lights, seal the drywall around those, and install the track lights.

Or some other kind of surface-mounted fixture.
 
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Old 04-05-13, 02:03 PM
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Thanks/ But I'm trying to avoid track lights. At least anything I've seen.

I was just thinking since I have 3 remodel recessed fixtures might as well use them. I'll probably spring for all new IC boxes though. I've realized I can use the old clip on trim piece.

Again though, I've had more issues trying to find a 4" HAlo can that will work.
Since I'm using 3/4" furring for the ceiling, I need a can that will extend that extra 3/4". The 4" one that I saw doesn't seem to do that. The 6" cans do. Maybe I should just attach lights to the furring. Would that work??
 
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Old 04-05-13, 03:51 PM
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If you want to use recessed lights, they need to be both IC and AT. The 6" new construction housings come with the largest selection of trims.

Maybe I should just attach lights to the furring. Would that work??
IDK. If your inspector will accept it then you're good.

Why are you adding the 3/4" furring? And are you planning to attach it with screws?
 
  #17  
Old 04-05-13, 05:49 PM
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Bill. Yes, I know, 6"ers seem to be the most popular and probably the least expensive oddly enough. I like em smaller especially in a small room.

I need the furring to meet up with the existing ceiling properly/. It's furred along with 3/4" of ceiling, so somehow I have to make up the additional 1/4".
I was thinking 1/4" plywood strips along with the 3/4" furring??
That said, I'm having a difficult time finding furring as anything at Lowes or HD is garbage. The wood used in making this house is amazingly hard. I can't quite figure how trees have gotten so soft.

I usually do everything with screws if I can. Why do you ask?

Thanks...
 
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Old 04-05-13, 09:04 PM
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6"ers seem to be the most popular and probably the least expensive oddly enough. I like em smaller especially in a small room.
I've been known to install an R-30 lamp in a 6" can with a black baffle trim and let it fake for a 4" can. Not a bad imitation, I think, especially for less than half the price.

I need the furring to meet up with the existing ceiling properly/. It's furred along with 3/4" of ceiling, so somehow I have to make up the additional 1/4".
I was thinking 1/4" plywood strips along with the 3/4" furring??
Yeah, or 1/4" lattice strips.

That said, I'm having a difficult time finding furring as anything at Lowes or HD is garbage. The wood used in making this house is amazingly hard. I can't quite figure how trees have gotten so soft.
They haven't; the wood we cut years ago gets a little bit harder every year, with age.
 
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Old 04-06-13, 01:35 PM
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Pictures always help, a manufactured house. For you, pp. 51, especially; http://www.huduser.org/Publications/PDF/nistir.pdf

ADA the drywall; Info-401: Air Barriers

IMHO, no cellulose for your application; BSI-043: Don't Be Dense

Gary
 
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Old 04-07-13, 05:54 PM
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Gary, Your links give me nothing. what's your point?
 
  #21  
Old 04-09-13, 02:56 PM
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The first link gave reasons why not to vent an attic in FL or use a vapor barrier on the ceiling, pp. 52 PDF/46 of article page. The ADA link is when you install your drywall ceiling, make it air-tight so no cool room air can go in attic space/hot attic air to conditioned cool living space.

Cellulose link was showing possible problems associated with your low attic clearance. Sorry if they were not clear enough... just ask, we are here to help!

Gary
 
  #22  
Old 04-10-13, 08:27 AM
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Thanks Gary. I couldn't find the information you refer to though. Sorry.
I guess I'm pretty dense packed........

speaking of which, this is what I'm going to use:
Shop Roxul 4-Pack 47-in L x 23-in W x 7-1/4-in D 30-R Stone Wool Insulation Batts at Lowes.com
 
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