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tommyxv 06-18-2013 11:00 PM

faced or unfaced
 
Howdy all,

I am getting ready to purchase the fiberglass insulation for my basement remodel.

Some info...It is a condition area. I live in Newark Delaware. I already put 2" XPS rigid foam directly on the concrete walls and also in the rim joists. I have two questions...

1) should I put faced or unfaced fiberglass in the rim and band joist on top of the XPS?

2) should I use faced for unfaced fiberglass in the 2x4 wall cavities?

Thanks

Windows on Wash 06-19-2013 07:17 AM

Unfaced on both if it were my home. The painted drywall should serve as your vapor control layer and class III vapor retarder.

I don't have the codes handy on my phone but I think, will have to check, you don't need one.

Use the air tight drywall approach.

Here you go: http://www.buildingscience.com/docum...commendations/

Don't need one.

tommyxv 06-19-2013 07:25 AM

Thanks for the reply. I see you are not too far from me, all the HD and Lowes don't seem to carry unfaced r-13 for the wall cavities, maybe r-19 for the rim/band joists. I guess just removing the kraft paper is the easier way to go?

Windows on Wash 06-19-2013 07:27 AM

Order it or use Roxul.

That or call an insulation supply house.

tommyxv 06-19-2013 07:32 AM

I will probably order it then. I'm having HD deliver 80 sheets of rock soon so I will just add it to the order.

Thx

Gary in WA 06-19-2013 03:57 PM

Unfaced in the wall, faced in the rims. You are in Zone 4, XPS over 1" thick with dew-point at 45%RH, Fig. 2- center; http://www.buildingscience.com/docum...nd-wall-design

Gary

tommyxv 06-19-2013 04:03 PM

Quote:

Originally Posted by Gary in WA (Post 1204035)
Unfaced in the wall, faced in the rims. You are in Zone 4, XPS over 1" thick with dew-point at 45%RH, Fig. 2- center; http://www.buildingscience.com/docum...nd-wall-design

Gary

Is it bad that I used 2" XPS?

Gary in WA 06-19-2013 05:02 PM

No, that's fine. Figuring your location, three coldest months average temps http://www.usclimatedata.com/climate...ation=USDE0043 of 35*F minus the 68*F basement temp = 33*F inside foamboard temp with R-19 floor insulation = 46*F/45%RH foamboard temp/relative humidity. Very close to the 45*F of the link, asphalt paper-faced would be best. Especially as the rim will be closed off from the direct heat transfer as a wall, it will run cooler equals; higher dew-point there to wet the framing. Use a low-expanding canned foam (window/door) rather than "Big gap filler" closed-cell= with less "give" for movement if an older house without new "engineered" framing; http://www.buildingscience.com/docum...d-but-strange/

Gary
PS. you could also use less fibrous insulation to keep the f.b. warmer if already ordered...

tommyxv 06-19-2013 05:18 PM

Gary you got me very confused now. LOL

I have not ordered any fiberglass yet. As of right now, I put 2" XPS in all the rim and band joists with spray foam to seal around the edges. I attached 2" XPS to all the concrete walls, seams caulked and taped with Dow Weather-mate.
2x4 walls are already framed tight to the XPS.

What is my next step then?

Thanks

tommyxv 06-20-2013 07:37 PM

Sorry for the bump... I am ordering the insulation tomorrow along with 70 sheets of mold resistant rock and want to make sure I am clear on what I should be ordering.

1) Faced fiberglass (preferrably asphalt paper-faced) on top of the 2" XPS foam board in the rim and band joist.

AND

2) Unfaced fiberglass inside 2x4 wall cavities.

Note: All walls and ceilings will be dry-walled

Thanks!

Gary in WA 06-20-2013 09:09 PM

Faced in the rims is correct, IF there is no more additional foamboard on the exterior there (it all has to do with the permeability of the siding/sheathing, including f.b.). Unfaced on the walls. With the Code required R-19 and your R-10 XPS, a cavity insulation of R-13 or R-15 (Roxul) is all you need. This (less mass cavity fiber) will raise the dew-point to a safer 51%RH in the rooms before condensation.

Gary

tommyxv 06-20-2013 09:46 PM

Thanks for the reply. I really like the Roxul product. I will have to see the total cost difference btw fiberglass and it.

I plan on running a dehumidifier as extra protection. My basement is dry with no leaks. I did the plastic on the slab test I only get a small damp/darker spot on the concrete after a few days, no water on the plastic.

Thanks again for you input and help.

Windows on Wash 06-21-2013 07:08 AM

You won't need to run a dehumidifier if you insulate the basement as you are proposing. That space will be tight as a drum and you won't have any humidity issues.

tommyxv 06-21-2013 08:25 AM

Quote:

Originally Posted by Windows on Wash (Post 1204885)
You won't need to run a dehumidifier if you insulate the basement as you are proposing. That space will be tight as a drum and you won't have any humidity issues.

very good then.

Thanks

Nailbags 06-21-2013 04:05 PM

Unfaced! Easier to deal with


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