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Old 01-11-2012, 01:38 PM   #16
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knee wall insulation help


thanks gary , ag and bubbler for your input im glad to know i can leave that up and its not goin to cause an issue. there is alot of conflicting info out there. also i agree with bubbler about exposed foam board . im sure it might b against code but i have wood all over the place exposed behind my knee wall. good pt on both sides thanks alot for your help

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Old 01-11-2012, 02:14 PM   #17
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Originally Posted by david szela View Post
also i agree with bubbler about exposed foam board . im sure it might b against code but i have wood all over the place exposed behind my knee wall.
Actually I wasn't intending it that way... I was actually intending to the give the impression of the OPPOSITE... I was pointing out that my potential installer had said that to me, and I was surprised to hear it, because although he's technically correct that they are both flammable, the foam board is much more flammable... It's like saying both a chopstick and a piece of paper are flammable... yes they are, both one is going to catch faster and burn faster...

Foam board ignites easily, burns fast, and releases toxic & choking fumes...

By comparison wood ignites with more difficultly, will probably burn slower, and will release smoke (but not nearly as acrid as the foam board).

I'm a believer that foam board should be covered--sandwiched between two less flammable substances.

In your case I think you could put plywood or drywall over the foam board to be code compliant as AGW mentioned, and it would reduce your risks if an ignition source were present in the attic space--like a workman's light held too close to it, a kid smoking a joint, or pyromaniac chipmunks...
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Old 01-11-2012, 02:34 PM   #18
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It is specifically against most current building codes to leave foam exposed ANYWHERE within a building, even within an attic or crawl space. Anyone who says you can leave it exposed is not adhering to the code. Argue all they want, it's in black and white text (2003 International Residential Code: R314.1.2 pertains to living spaces, R314.2.3 pertains to attics and crawlspaces.)

It must be covered by 1/4" plywood, 3/8" particle board, 1/4" hardboard, 3/8" gwb (gypsum wall board, a.k.a. sheetrock), or 0.016" thick corrosion-resistant steel sheeting for use as an ignition and thermal barrier. The foil face that is on some foams is NOT considered an approved ignition barrier.

Yes, wood is flammable, but as bubbler noted it is not Extremely flammable and heavily toxic when burned like foam is.
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Old 01-11-2012, 03:40 PM   #19
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thanks guys and i will take your advice and cover it over . this is why these websites are great to have. i can see your point now. im all about saftey . I wonder if the bubbler would have left that like it was exposed , how many inspecters would have caught that. since both your contractors along with many others i guess wouldnt seem bothered by it.
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Old 01-11-2012, 04:05 PM   #20
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Originally Posted by david szela View Post
thanks guys and i will take your advice and cover it over . this is why these websites are great to have. i can see your point now. im all about saftey . I wonder if the bubbler would have left that like it was exposed , how many inspecters would have caught that. since both your contractors along with many others i guess wouldnt seem bothered by it.
I had two sets of pros come in, both of them were planning to install foam board WITHOUT covering it with a material like plywood, steel or "gwb".

The first company wanted to cover the whole wall--same as you have.

The second company didn't offer that up (probably because I had a price ceiling that it didn't fit under), but did cover the backs of the access hatches to my knee wall attics with foam... it's the kind w/ the foil. As AGW points out, this isn't enough according to the code, it should be protected. So what I will be doing on my own is adding another layer of plywood and some 1x material to create a sort of sandwich that encloses the foam (in essence I'm making my own hollow door w/ foam inside).

In my area there were no permits required to do the insulation work I had done, and there was no town inspection process.

Maybe a keen eyed home inspector might notice this at the time of sale and indicate to a buyer that this is unacceptable, but who knows... I know my home inspector walked right past major water damage when I was buying, he never saw it, frankly I didn't either, but I'm not a professional home inspector and in hind sight it was painfully obvious, particularly since there was evidence of water damage (staining) in the knee wall directly above...
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Old 01-11-2012, 07:46 PM   #21
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sorry to hear about the water damage and thanks again for your help good luck with your projects
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Old 01-12-2012, 05:31 PM   #22
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In answer about the sneaky pros... The attic has to meet certain requirements to allow SPF or rigid foam board left uncovered. The SPF industry well knows this. The foam manufacturers have written amendments for their certain products, used as listed in attics. These are written by the “I” Code writers; IBC, IRC, and IECC. This explains it better: http://www.ncfi.com/Insulation/uploa...%20SF0608L.pdf

Owen Corning pink board in attics: #4.2.1: http://commercial.owenscorning.com/a...79af27e5d.pdfI

I am merely showing the reason spray foam professionals may not cover it, and if you are under an “I” Code, there is information you may be missing. I would cover it whenever convenient to do so, just for the fire safety issue.

Here is one from Dow, follow the other links/questions to learn more;
http://dow-styrofoam.custhelp.com/ap...KkNueDl5R2s%3D

You may check the certain type listing: http://dow-styrofoam.custhelp.com/app/answers/detail/a_id/3891/~/what-are-the-astm-c578-classifications-for-styrofoam%E2%84%A2-brand-extruded

http://dow-styrofoam.custhelp.com/ap...9mbS1Oaw%3D%3D

When using a foam board in the crawl space, check the type for application, this can be left uncovered, with the conditions listed: http://www.icc-es.org/reports/pdf_fi...S/ESR-2142.pdf
So the pros are not trying to sneak something by inspection, their livelihood depends on meeting code. One lawsuit is all it would take.

Gary
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Old 01-13-2012, 10:16 AM   #23
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We've been through this before GBR...Here's an excerpt from the 2009 International Building Code:

SECTION 2603 - FOAM PLASTIC INSULATION

2603.4 Thermal Barrier. Except as provided for in Sections 2603.4.1 and 2603.9, foam plastic shall be separated from the interior of the building by an approved thermal barrier of 1/2-inch (12.7mm) gypsum wallboard or equivalent thermal barrier material that will limit the average temperature rise of the unexposed surface to not more than 250degF (102degC) after 15 minutes of fire exposure, complying with the standard time-temperature curve of ASTM E 119 or UL 263. The thermal barrier shall be installed in such a manner that it will remain in place for 15 minutes based on FM 4880, UL1040, NFPA 286 or UL 1715. Combustible concealed spaces shall comply with Section 717.

2603.4.1 Thermal barrier not required. The thermal barrier specified in Section 2603.4 is not required under the conditions set forth in Sections 2603.4.1.1 through 2603.4.1.13.

(Sections 2603.4.1.1 -> 2603.4.1.5 and 2603.4.1.7 -> 2603.4.1.13 don't pertain to this topic)

2603.4.1.6 Attics and Crawl Spaces. Within an attic or crawl space where entry is made only for service of utilities, foam plastic insulation shall be protected against ignition by 1 1/2-inch-thick (38mm) mineral fiber insulation; 1/4-inch-thick (6.4mm) wood structural panel, particleboard or hardboard; 3/8-inch-thick (9.5mm) gypsum wallboard, corrosion-resistant steel having a base metal thickness of 0.016 inch (0.4mm) or other approved material installed in such a manner that the foam plastic insulation is not exposed. The protective covering shall be consistent with the requirements for the type of construction.

2603.9 Special approval. Foam plastic shall not be required to comply with the requirements of Sections 2603.4 through 2603.7 where specifically approved based on large-scale tests such as, but not limited to, NFPA 286 (with the acceptance criteria of Section 803.2), FM 4880, UL 1040 or UL 1715. Such testing shall be related to the actual end-use configuration and be performed on the finished manufactured foam plastic assembly in the maximum thickness intended for use. Foam plastics that are used as interior finish on the basis of special tests shall also conform to the flame spread requirements of Chapter 8. Assemblies tested shall include seams, joints, and other typical details used in the installation of the assembly and shall be tested in the manner intended for use.

The evaluation reports you provided can only be administered under the direction of Section 2603.9 noted above. The homeowner/contractor would have to provide the evaluation reports along with documentation that the intended assembly meets the code derived requirements. Since most home attics are built of flammable wood, filled with flammable materials (boxes, etc.) and are not sprinklered, this is a difficult thing to have passed. Usually the inspectors have them paint it with an intumescent paint at minimum.

So, GBR, please inform people, correctly, that foam plastic insulation NEEDS TO BE COVERED per code, UNLESS THEY HAVE SPECIFIC WRITTEN APPROVAL FROM THEIR BUILDING OFFICIAL.
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Old 01-13-2012, 07:34 PM   #24
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There seems to be differing opinions on this.

The end all result is that you better have approval from the code enforcement officials in your area.

Here is a snippet from the ICC-ES: (http://www.google.com/url?sa=t&rct=j...pZArAG-2p0cSFA)

4.5.11.5.1.1 Foam plastic insulation installed in attics where entry is made only for service of
utilities shall be protected by an ignition barrier as set forth in IBC Section 2603.4.1.6, IRC
Section R314.5.3 or Exception 4 of UBC Section 2602.4, except as noted in Section
4.5.11.5.1.2. Utilities include, but are not limited to, mechanical equipment, electrical wiring,
fans, plumbing, gas or electric hot water heaters, and gas or electric furnaces.

4.5.11.5.1.2 The ignition barrier shall not be required when satisfactory testing is conducted in
accordance with either Section 4.5.11.5.1.2.1 or 4.5.11.5.1.2.2.


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Old 01-13-2012, 07:35 PM   #25
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FYI...it is always better to be safe than sorry.

Foam does not necessarily combust very readily but it does off gas pretty rapidly.
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