Open Cell Foam in Roof Rafters

[TimNY]

I just got a compliance certificate on a home that states they used open cell foam. Ok, first issue is it was supposed to be closed cell, so little did I know that when I was there there should have been a vapor barrier installed. Sure hope they installed it, but that's a whole other issue.

Does anybody have any input on open cell in the rafters? I read that it is better because it won't trap roof leaks at the deck. At the very least, I have an issue with a vapor barrier. Without baffles (as is typical with fiberglass in the rafters), is there any way this can comply?

Any suggestions/pitfalls/advice would be appreciated. I've never had a situation with open cell in the rafters. I have a call into the manufacturer, but apparently only one person in the entire company can answer questions.. and he's traveling.

 

[TimNY]

Got a call back from the manufacturer. There was an update in 2004 to eliminated ventilation, and it's also now in the 2006+ codes.. section R806.4.. Off to check my books. NY is on 2003 and I don't remember adoption of any changes, but...

 

[peach]

I've never seen closed cell on any wood application; it's just been in basements where ground water is an issue. the spray foam insulation has yet to have a track record on performance. In the case of any attic mounted mechanical equipment, I kind of like the idea of having the attic part of the conditioned space, since (especially with sprinklers being required), keeping it warm is a better option than the alternate of the sprinkler pipes freezing. BUT, it's unproven...

 

[TimNY]

Starting in the 2006 IRC unvented attic are permitted (actually there was a 2004 addendum to the 2003 code). In that section it specifically lists spray foam. It's starting to get pretty popular here.

It's a little different here since we are on the 2003, so I am going by an ES report for the product.

WHat I have had to explain so far.. Open cell foam is air permeable and need a vapor barrier over the walls. Air-impermeable foam does not necessarily mean it is vapor impermeable.. Vapor barrier may be required.

When applied to the underside of the roof decking, no vapor barrier can be applied to the ceiling of the top floor (that was about the only thing that I found easy to understand).

Move on to thermal barriers.. no thermal barrier installed.. move to ignition barriers.. no ignition barrier installed move to acceptable test standards.. no compliance with test standards (did get one that said "modified" test).. rinse, repeat.

ES report says their ignition barrier product SHALL be applied to foam in attics. Didn't stick around to talk about that one.

 

[peach]

the air permeable vs. vapor permeable issue already exists.. once water condenses, it's an issue in walls (which is why I don't like vapor barriers). It's a one side versus the other. Since I assume we're talking icenyene, I carry a lighter.. it doesn't sustain combustion. When the code addresses foam, I believe they are talking about styrofoam (which does).

spray foam insulation has yet to really have a track record; overly tight houses that the code requires do... open up any of them and see how much rot you find.

 

[TimNY]

Yeah the whole vapor barrier thing could have it's own forum. In the meantime the minimum requirement of the code has to be enforced.

Since there is relatively little discussion on the matter it gets confusing real quick. I certainly am no expert and have exchanged several emails and had a phone conversation with the manufacturer to get their input. ie, this is how I interpret it, do you have anything to the contrary. I must say they have been very good, and even went so far as to say they would help with any foam question, regardless of manufacturer.

As far as combustion, the ES report for the specific product requires the ignition barrier to be applied. Never tried to light anything on fire. Diesel won't ignite either... but..

 

[peach]

It's a newer product with no track record; if they need to rock the rafters/trusses there shouldn't be an issue there, either as the bottom chord of the roof should be able to tak the additional load. I'm a curious creature who would rather be able to observe over time... on the right project, with the right client.

 

[Robert Ellenberg]

There is a lot being written by some of the building science engineers who are studying the interactions of the foams, temperatures, moisture, etc. Building Science Corp. website is a good one and a lot is written by Maritn Holladay on the Green Building Advisor website.

 

[TimNY]

There is a lot being written by some of the building science engineers who are studying the interactions of the foams, temperatures, moisture, etc. Building Science Corp. website is a good one and a lot is written by Maritn Holladay on the Green Building Advisor website.

Thank you, Robert. I think it is great, in theory. There's no track record like peach stated, but this is one of those things I really would like to work as well as they say. Not so much for the R-value as much as the air sealing.

I have to check that site and see if they have some sort of inspector's guide. I already had the disgruntled contractor in the office "we do this everywhere, nobody ever said anything". At which point he provided the specs for the Pittsburg Paint vapor barrier they are using over the GWB. Not sure if it was planned like that or what a result of my inquiries.

When I contacted DOS they asked what code it was built under. When I said the code based on the 2003 IRC they basically said "hope it has an ES report"

 

[Architect1281]

TIM NY I have had way too many go rounds with the expanding foam sales representative on wether or not ther product can be placed where it is

requires a vapor retarder, or worse requires a flame barrier.

It has been my pleasure to educate the sales reps and installers (Factory Trained ?? ) of a small article called ESR reports

All manufactures have them -(or no installation allowed in RI)

the ES Reports list all locations, conditions, and required coverage in locations be it wall, crawlspace, attic, hot or cold design

even the code they were tested to comply with. IBC and IRC

IRC is easy but IBC usuall is limited to 3B and 5B construction types- which sales reps say whats' that mean???

most of the products require flame barriers in attics and crawl spaces - unless it is for acces to service mechanical equipment only.

my office has rulled that if the volume of such spaces PROVIDES enough space to qualify as ATTIC STORAGE that is the for OTHER than Acces to only service.

and a note from mom stating we wont store the christmas ornaments in that space is NG.

Produce the ESR reports for these products for the folks - and when they are done reading them then ask how they intend to comply

As far as what coatings can they use - ONLY THE ONES LISTED ON THE ESR REPORT!.

 

[conarb]

Architect:

Perhaps everyone has already forgotten the Rhode Island Station nightclub fire?

 

[Francis Vineyard]

TimNY

The 2009 and 2006 has more specific conditions than the 2003. The ESR's usually includes details for each code edition. 2009 states that the air impermeable insulation must be a vapor retarder that is having a presence rating of 1.0 or less. The ESR's usually corresponds with the code.

http://www.buildingscience.com/documents/guides-and-manuals/irc-faqs/irc-faq-conditioned-attics/files/IRC_FAQ%20Conditioned%20Attic_rev2010.pdf

http://www.buildingscience.com/documents/guides-and-manuals/irc-faqs/irc-faq-conditioned-attics/

If using a thermal barrier other than ½ inch gypsum be sure the coatings references AC377 criteria meeting ASTM E 119. http://www.icc-es.org/criteria/dsp.cfm?ac_code=AC377

 

[Architect1281]

Conarb we are reminded here on a regular basis for all the wrong reasons

"Oh you're making me do this because of the fire" rings out al too often.

my response is

"No we are ounly making you do the worst possible job allowed by law, and it seems you are striving not to attain even that standard."

 

[TimNY]

Thanks for all the helpful replies. I did check out buildingscience.com after Robert had mentioned it. It is now bookmarked-- what a great site!

Here is the esr: http://www.icc-es.org/reports/pdf_files/ICC-ES/ESR-2847.pdf

Maybe it's me, but I find 4.4.2 confusing. I am reading it as the TF9000 intumescent must be applied if there is no prescriptive thermal barrier or prescriptive ignition barrier, AND items a-e must be met.

What do you guys think? The report doesn't have a 2003 equivalent at the end like they do for 2006, so I would be more apt to go for the newest methods as an alternative method.

 

[Yankee]

It is used here all the time, (talking closed cell). What am I missing? Flame Spread & Smoke Development index meet or exceed. Perm rate is ok. Thermal barrier where required. What is that about the type of commercial roof it is allowed on, not familiar with that?

 

[Francis Vineyard]

TimNY

It is confusing! Usually low density foam require an ignition or thermal barrier when more than 3½ inches on the walls similarly with R314.5.11

I would call the manufacturers number listed on the report then ICC

 

[TimNY]

It is used here all the time, (talking closed cell). What am I missing? Flame Spread & Smoke Development index meet or exceed. Perm rate is ok. Thermal barrier where required. What is that about the type of commercial roof it is allowed on, not familiar with that?

Yankee, it is definitely confusing. I sent an email off the the manufacturer telling them how I interpreted it, and to see if they agreed and/or if other AHJ's agreed.

From the ESR: "the foam plastic must be covered with... the TS9000 intumescent coating"

Don;t have my books atm but I believe if you don't have a prescriptive thermal barrier and you don't have a prescriptive ignition barrier you are sent to another section that says it has to pass a UL, ASTM or FM test. I got the spec sheet for this product and it said it met one of the tests "modified per appendix x", and we've been down the "modified" road with the foam fire blocking material.

I am guessing they have to apply the intumescent to pass the tests, but am definitely open to other input.

I would think that if the ES report says it has to be done (this report is 2 months old), the ESR prevails over anything else?

EDIT: Yankee, when you see the closed cell (I have open cell here) in the attic rafters, how do they typically provide the thermal or ignition barrier?

 

[Yankee]

Thermal barrier is gyp board, or in combination with fiberglass insulation. . . ignition barrier, the way I understand it, if the flame spread & smoke development of the product meet or exceed values, no additional ignition barrier is required. In the beginning, some closed cell foams did not meet the values but contractors here have stopped using those for the most part. Probably 75% around here will use foam someplace.

here is an interesting table

http://www.foam-tech.com/theory/firebarriers.htm

 

[Francis Vineyard]

There are currently two approved thermal barriers coatings I'm aware of that meet ASTM E 119 using AC377 criteria. Most all SFP manufacturers recommend a specific ignition barrier coating for their products. The use of coatings or paints are the most popular here as oppose to the code prescriptive list.

The new appendix x simply replaces the previous appendix b test methods using a set up that no longer requires a comparison test.

“On June 1, 2010, the testing requirements described in Section A1.2.2 will expire, and ICC-ES will no longer accept ESR applications using this test data after that date. ESR's written to this standard will be valid until December 31, 2010. All applicable evaluation reports will be revised by December 31, 2010 to delete assemblies based on this testing. Report holders can submit data from new test methods (A1.2.1 or Appendix X) to attain compliance with the new standard.”

http://www.sprayfoam.org/index.php?page_id=4519

Yankee where do you come up with using fiberglass insulation?

 

[Yankee]

per R316.5.3 #3 1.5" mineral fiber insulation provides the thermal barrier and protects against ignition. Mineral fiber (rock wool) and fiberglass have similar properties with mineral fiber being a somewhat better insulator. Often the application here is 2 inches of foam to prevent infiltration covered with batts of fiberglass (unfaced) to increase the insulation and provide thermal barrier and ignition protection.

Now I'll be asked for the testing reports for mineral wool and/or fiberglass insulation (non-combustable materials). I don't have that at the moment.

 

[TimNY]

R314.3 requires the smoke developed/flame spread except as noted in 314.5 and 314.6.

R314.4 requires the thermal barrier (at this point, you have a foam that meets the flame spread/smoke criteria and the thermal barrier is still required)

R314.6.3 says you can omit the thermal barrier, but you must furnish the prescriptive ignition barrier, unless you meet R314.6

ESR says install their intumescent, which I suppose it required to pass the testing in R314.6.

So, that's where I am at now. I an not interpreting the code to say that if it meets a certain flame spread/smoke produced no barrier is required. I think the code is saying that in certain areas you do not have to meet the flame/smoke criteria, but in all cases you must furnish either a thermal or ignition barrier.

But, I am open to other interpretations.

 

[Francis Vineyard]

The response I recieved from Lapolla;

Vineyard,

I asked the technical director Steve Williams to address this question we just had that ICC updated. Please look at his answer. All open cell foams will need Ignition barrier starting January 1, 2011. They can’t pass the new ACC 377 appendix X only closed cell can. Sorry I missed you on the phone today.

Thanks

You must use the Ignition barrier over the FL500.

The first section shows that an ignition barrier must be used if entry into the attic is for service of utilities only and so forth.

The second section describes the use of the TF9000 as an ALTERNATIVE to the PRESCRIPTIVE. Meaning you still must use something but it does not have to be one of the items defined as a prescriptive ignition barrier by the code as long as you have the testing required in AC377.

Steve

Troy Herring

Insulation Products Manager

 

[Jobsaver]

There are currently two approved thermal barriers coatings I'm aware of that meet ASTM E 119 using AC377 criteria. Most all SFP manufacturers recommend a specific ignition barrier coating for their products. The use of coatings or paints are the most popular here as oppose to the code prescriptive list.

Francis: What are the trade names or brand names of these coatings?

 

[TimNY]

THanks Francis. I had sent an email over to Troy on Friday but I won't be back in the office until Monday.

So where does this leave us if the attic is also used for storage. Again, I'm sans code books but I believe the foam would have to meet the flame spread and smoke developed index and a thermal barrier (ie gwb) installed?