Retrofit cellulose vs. blown in fiberglass

[cdservices]

In existing homes, blown-in cellulose (from interior or exterior) is much more popular
than blown-in fiberglass. Am wondering why. Similar cost and R-value, but fiberglass is more immune to moisture absorption.

thanks,

CD

[Martin Holladay]

CD,
Dense-packed cellulose is much more effective than fiberglass at reducing the rate of air leakage.

[Bluewoodrock]

CD,
Dense-packed cellulose is much more effective than fiberglass at reducing the rate of air leakage.

Not According to the fiberglass guys.

http://www.specjm.com/files/pdf/BID-0108.pdf

Disclaimer- I just did a quick google on dense pack fiberglass, I haven't seen any of their testing.

[ThingOfBeauty]

They just came out with this material, and with the testing that it reduces air leakage on par with cellulose, so probably the novelty is why people haven't used it much.
It's more expensive though. I also find the fibers extra irritating to my throat. That's given me second thoughts about using it at all. (We've used it in new construction not retrofit.)
BPI changed their protocols to allow any insulation shown to reduce air leakage to be accepted for wall retrofit. I believe the protocol attempts to compare any new material to 3.5lb cellulose.

[Jason P]

I have been using the fiberglass BIBS for the past year in new construction. It gives you a R-15 in a 2x4 wall cavity. The key to this insulation performing well is sealing all penetrations. Just recently we had a blower door test done and achieved favorable results without spending a ton of extra money of foam insulation.

[cdservices]

In a lot of existing work you can't air seal well because the financial decision to leave plaster in place has been made. Air sealing depends on density of blown in fiber. It makes sense that dense fiberglass is as air resistant as dense cellulose.

[Mark Parlee]

Not According to the fiberglass guys.

http://www.specjm.com/files/pdf/BID-0108.pdf

Disclaimer- I just did a quick google on dense pack fiberglass, I haven't seen any of their testing.

• Provides significantly higher airflow resistance
than cellulose (per ASTM C522 measurements

Do you have a copy of ASTM C522

I do not but I do wonder what and how this test is performed. They always refer to ASTM but never provide it. I do realize it is because they cannot give it out you have to buy it for yourself.
sometimes I do find comentary on the standard; this may be it
http://www.bpi.org/Web%20Download/BP...est_Method.pdf

[Dick Seibert]

Mark:

ASTM test or not, they have no ES Report, so a sharp inspector would reject it. Specifically an ANSI NER 549 republished by ES Reports. Look through here to find the NER 549 I posted above.

[worthy]

Thanks Deadeye Dick!

[ThingOfBeauty]

interesting that JM doesn't have an ES report either for their standard batt material OR for "spider" loose-fill/wet-spray/dense-pack material. ComfortTherm is their plastic-wrapped batt material.
Dick, explain the ES report regime. Are there materials that don't require a report? I mean 2x4s don't have an evaluation report, they're accepted under normal grading rules or something, right? Maybe common materials like loose fiberglass don't require a special report?

[worthy]

Deadeye directed us to the ES Report for the encapsulated batt material, which has no reference to air sealing.

Under the Ontario Building Code (OBC) a slew of building products must meet CGSB (Canadian General Standards Board) standards and are given a listing number. But you can't access CGSB reports without charge. ( Canadian Construction and Materials Centre (CCMC ), affiliated with the National Research Centre (NRC) also tests and certiifes many products, though there's no reference to them in the OBC.)

However, the JM promotional sheet for Canada cites compliance with CAN/UL S702 which does cover loose fill, but not used in walls. Viz: It also applies to loose fill mineral fibre thermal insulation when used in unconfined spaces with slopes not exceeding 4.5:12.

[Dick Seibert]

Dick, explain the ES report regime. Are there materials that don't require a report? I mean 2x4s don't have an evaluation report, they're accepted under normal grading rules or something, right? Maybe common materials like loose fiberglass don't require a special report?

I should learn more about this myself since it has become such an issue, in the past the first I saw them required was for all metal fireplaces, by 1971 I was building a 65 unit garden apartment complex and they were requiring them for all bolts and hangers, it has always been at the discretion of the AHJ. On Sim's Woodside house I was there the first day of the 7 day framing inspection, he had two 3" three-ring binders full of ES Reports along with some additional structural details and the inspector was constantly demanding copies of ES Reports, since there were several different Hardy Frames he was demanding an ES Report for each one. The time to retrieve all of them made me think that it would be better to have them in search-able electronic format and then they would be easily accessible to print out for the inspector. As inspectors become better educated and more competent look to see a lot more of this.

[worthy]

I only build single houses at a time, two when I was foolish. The inspectors don't even have a Building Code at hand. If there's a difference of opinion, we agree to meet later and compare scripture.

To the matter at hand, is it resolved that JM has, as Desi might say, "some 'splainin' to do?"

[Dick Seibert]

The inspectors don't even have a Building Code at hand. If there's a difference of opinion, we agree to meet later and compare scripture.

Gary:

Look for this to change, here in the states inspectors even in the developing areas of the nation are becoming more astute, one of the driving forces in the creation of the ICC was a threat from the Feds to create a national building code enforced by a national agency to enforce the code equally among all states, Martin has said on a couple of occasions that Vermont doesn't even have a building code or contractor licensing, the Feds are not going to let that go on for long, and disasters like Katrina and the earthquake in Chile, Haiti, and now Japan are going to hasten the adoption and strict enforcement of codes. This year is the 200th anniversary of the New Madrid earthquake, and there was supposed to be a big push this year to bring earthquake-hurricane-tornado safety to the entire nation, I have to wonder if it hasn't been derailed by the adoption of these silly green and energy codes that do nothing for safety and actually make buildings more unhealthy.

[worthy]

So the same gang behind "green Codes" and mandatory mercury lightbulbs--not to mention irradiating pornoscanners--will bring to the Benighted States of America national earthquake-hurricane-tornado safety!

Dream on!

Much like their counterparts in Japan created false "security" behind worse than useless seawalls and unsafe nuclear plants, I take it.

Doesn't someone here have a tagline, "you build to Code, you've failed"?