Owens Corning R19

[jar546]

Owens Corning R19 6-1/4" Fiberglass Batt insulation is reduced to R18 when placed into a 2x6 wood stud cavity.

I never knew that.

 

[cda]

Why yes Timmy it does,

Learned that when trying to reinsulate some of my walls.

Fiberglass Insulation

 

[RLGA]

Thermal bridging will get you all the time. Metal studs also will reduce the R value (even more so than wood studs, since metal is a better conductor of heat).

 

[jar546]

Thank goodness all of the metal studs in my house are interior partition studs away from the exterior walls.

 

[rogerpa]

http://www.owenscorning.com/around/insulation/CompressionChart.xls

 

[RLGA]

Thus the big push by the IECC for continuous insulation on the exterior...which feeds the NFPA 285 testing issues.

 

[steveray]

Thank goodness all of the metal studs in my house are interior partition studs away from the exterior walls.

Luckily I did not use any bushings, so the NM I pulled keeps the studs nice and toasty!

 

[peach]

any time we compress insulation, we reduce the R value..

 

[MASSDRIVER]

any time we compress insulation, we reduce the R value..

If we uncompressed it does it get higher r value?

Brent

 

[conarb]

I've got an entire house full of http://www.jlconline.com/insulation/overbaked-fiberglass-batts-linked-to-odor-problems.aspx' rel="external nofollow">'>Owens Corning stinking batts, now that the home is plastered and both the walls and ceilings are covered the smell has gone away, but if you go down into the crawl space you can still smell it.

 

[jwilly3879]

That's why I prefer Johns Manville.

 

[jar546]

That's why I prefer Johns Manville.

Absolutely. That's why New Jersey smells like it does. The factories leave the stink behind so the products don't smell.

 

[Francis Vineyard]

rogerpa the link posted above is broken: "error page not found".

http://www.thebuildingcodeforum.com/forum/residential-energy-codes/10221-ducts-unconditioned-attics.html

Francis

 

[rogerpa]

It was working the day that I posted. OC has revised their site and removed the chart. I couldn't find it anywhere on the new site, but I found another version of it here-Owens Corning Fiberglass Batt Compression Chart - Num Sum

 

[steveray]

What do you get when you stuff R38 in 6"?...A big negative on your inspection results Woodchuck!

 

[rogerpa]

I don't know why this chart keeps disappearing from the net, but I have it saved on my computer. It looks to me like the installed thickness is only 4-1/4". You'll be lucky to get R-19 installed.

View attachment 1041

Fiber Glass Insulation Compression Chart1.pdf

Fiber Glass Insulation Compression Chart1.pdf

 

[conarb]

Roger:

If the requirement is for R-19 and the manufacturer states that the product is rated at R-19 in a 2x6 wall isn't the inspector required to approve it and not get into other issues (like thermal bridging)? All I've ever had an inspector do is check the R-rating on the insulation to be sure it complies with my Title 24 requirements.

 

[rogerpa]

Dick:

R-19 is 6" and is designed fo. When compressed into a 2 x 6 wall (5-1/2") it becomes R-18.

 

[rogerpa]

Try again. R-19 is 6" and is designed to go in the ceiling. When compressed into a 2 x 6 wall (5-1/2") it becomes R-18. The energy people made a big deal about this at the Palm Springs hearings. The FG manufacturers could fix this if they wanted to; after all they have an R-21 that is 5-1/2". Yes, under the prescriptive path you just add the R-values. If you are using a performance path you calculate the components including air films for both the cavity and the framing and apply a percentage of the overall wall framing.

See TABLE 502.2.3.1(1) WALL ASSEMBLIES here:http://publicecodes.cyberregs.com/icod/iecc/2003/icod_iecc_2003_app.htm?bu=IC-P-2003-000014&bu2=IC-P-2003-000017

 

[Glenn]

Footnote "a" in the table addresses this.