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-   -   Faced vs Unfaced insulation (http://www.diychatroom.com/f103/faced-vs-unfaced-insulation-196496/)

Dmi 02-18-2014 11:59 AM

Faced vs Unfaced insulation
 
Hi, all,

I am new to these forums but I've read up on some threads already.
My project: re-insulating my attic.

I have a split house built in 1959 and it looks like i have original insulation called RockWool manufactured somewhere upstate New York (I will attach a pic if anyone asks).

Here's what I want to do:
Remove old insulation and install new one (one faced and one unfaced on top).

Here's my problem:
They do not sell faced R-30 insulation in rolls neither at HomeDepot nor at Lowes, only in batts.

My question:
Should I go with batts? It looks like they are harder to work with (I have a very gradual roof, so ideally, I'd like to just roll it towards the eave of the roof.
Or, I can put plastic wrap (kinda like house wrap) underneath the unfaced fiberglass insulation. Is it advisable to do that?

Let me know your thoughts.

P.S. Yes, I've read DIY_Guide_May_2008.pdf from EnergyStar and sealed most of what they suggest already. Anybody knows if there's a more recent version or better version of that guide?

Thanks,

Dimmi

Windows on Wash 02-18-2014 06:00 PM

Dimmi,

Don't bother with the batts and certainly not with two vapor control layers at opposite end.

If you want to remove the insulation, at that point, do all the air sealing.

After that, loose fill blow in the insulation.

Gary in WA 02-18-2014 07:11 PM

Just copied another of my recent answers;If just blow-in cellulose/FG, leave the old, but cover with a housewrap over the fiberglass (the rough surface of blow-in gives 10-50% more convective loops to rob your rated R-value). The batts are fine for low slope (restricted headroom and lower insulation dams around scuttle hole access) or with standard joist spacing, but blow-in is easier with multiple obstructions. IMO, need an elevated walkway for any HVAC - OR (removable) batts just from the attic scuttle to unit for filter changes. Just raking blow-in aside for access and replacing leaves air pockets (de-rating the R-value) because the insulation clumps up with further movement. The FG batts are available in higher densities than the blow-in for perimeter application where roof slope interferes with full R-value. May also use stacked/sloped rigid foam board over the exterior walls (1' wide) for maximum insulation in that restricted height. Be sure to air seal the wiring/plumbing holes/chases and around chimney before adding new anything; http://www.google.com/url?sa=t&sourc...wWATQw&cad=rja

1. Any cathedral ceilings to warrant the vapor barrier?

Which Zone- #4 doesn't require a vapor control layer; http://energycode.pnl.gov/EnergyCode...e=New%20Jersey

2. #5 requires faced (asphalt paper); http://www.buildingscience.com/docum...commendations/

More guides for you; http://www.google.com/url?sa=t&rct=j...SUjxzy5AmI2XUg

http://www.buildingscience.com/docum...sealing-guide/

May be a dupli.; http://www.nybtg.com/downloads/therm..._checklist.pdf

good one; http://www.google.com/url?sa=t&rct=j...0DS4dFcgBoDHzQ

Did you seal the basement/crawl against stack effect; http://www.wag-aic.org/1999/WAG_99_baker.pdf

Gary

Dmi 02-18-2014 08:37 PM

Thanks for the replies guys.
Yes, I am sealing the attic - recess lighting, chimney, electrical wires, etc. Haven't got to sealing the basement yet.

I thought I would go with batts of faced R30 but apparently they are twice as expensive as unfaced R30 (80c/sq ft vs 40c/sq ft).
So I decided to go with faced R19 in rolls for now and then put in another layer of unfaced R30 on top. Which will give me same cost as just faced R30 but R49 total.

Thoughts?

Windows on Wash 02-18-2014 11:13 PM

Why not loose fill?

Easier to install and usually cheaper.

Gary in WA 02-20-2014 07:07 PM

http://www.diychatroom.com/f103/my-a...196546/index2/

Gary

Dmi 03-04-2014 09:51 PM

Thanks for all the suggestions, guys. I am now mostly done. I removed the old insulation and covered with R-19. Next month maybe I'll put R-30 on top.

Our master bedroom is over garage though and still pretty cold (even after sealing and insulation. It does have 4 windows in it though which of course contribute to the problem.

Question: how do I insulate from the garage side so my floor would be warmer?


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