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cmkavala
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| 07/06/2009 5:37 PM |
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Posted By CTP on 07/06/2009 4:31 PM
I also mentioned that I am working on getting that info and will be more specific with documentation as it relates to other metal roofing materials.
What specifically have you done to check the integrity of your roof sips under the brown stone coated metal roofs? Do you have specific documentation or studies that challenges Mr. Miller's comments?
Craig Payne
Eco-Panels CTP;
please post facts when you have some to post
I wouldn't conduct destructive testing on any system that shows no problems.
I am not challenging Mr. Millers studies whatsoever, I am assuming they are all accurate, but they have nothing to do with SIPs or EPS, but you insist on trying to link then somehow to bolster your PU panels
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Chris Kavala
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CathyK
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| 07/06/2009 5:58 PM |
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| All of this discussion has, indeed, been interesting but a bit overwhelming from my non-technical perspective! Thanks for the on-going debate. It will be interesting to hear more about what Craig finds out from the Oak Ridge lab at a later date. Cathy |
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jonr
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| 07/07/2009 8:40 AM |
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Anyone looking for a breathable radiant barrier might look at Tyvek® AtticWrap™.
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Dana1
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| 07/08/2009 8:33 AM |
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Worries about EPS SIPs failing under the heat are unfounded- there's a huge and competitive biz in EPS roofing insulation- there simply couldn't be if it were prone to thermal degradation under roofing (of any type.) The difference between a OSB-nailer-faced EPS roofing panel and a SIP is pretty much the presence/absence of the interior OSB, eh? ;-)
If this is in a cooling dominated climate and the SIP has an R-value of less than R25 there may be a measurable performance difference that would make a venting gap between the metal and the SIP worthwhile. In areas where snow loads linger for days/weeks, a vent gap between the roofing & the roof deck is pretty much a requirement. See p.73 & 75 of this document:
http://www.sips.org/elements/uploads/fckeditor/file/Alex%20Lukachko%20%5BCompatibility%20Mode%5D.pdf
High rainfall & high humidity areas are likely to benefit from a venting gap too. When in doubt, vent between the roofing & roof deck, it's always the safer (and higher thermal performance) option.
In cooling dominated climates it might be worth opting for a "cool roof" versions of the roofing with an optimized solar-reflectivity/infra-red emissivity ratio, eg. Galvalume.) Standard roofing felt is good everywhere, but you might consider using Ice & snow barrier in the valleys. Don't sweat the vapor trap issues TOO much- OSB faced EPS SIPs have some drying capacity, EPS is not nearly as vapor-retardent as polyurethane, (or even XPS), but covering the entire roof with an impermeable material will likely create mold issues in the exterior OSB facing. There are semi-permeable liquid-applied solutions that might be used instead of standard roofing felt as well. |
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Sip Supply Inc
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| 07/08/2009 12:17 PM |
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Dana1;
great point! there are millions of sq.ft. of commercial torch down roofing directly over EPS |
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info@sipsupplyinc.com |
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Dana1
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| 07/08/2009 1:10 PM |
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Posted By Sip Supply Inc on 07/08/2009 12:17 PM
Dana1;
great point! there are millions of sq.ft. of commercial torch down roofing directly over EPS
...and it's all defective & melting after sitting in the sun, I'm sure. 
(Talk about a red herring! There are sometimes issues with EPS interacting with
plasticizers in other building components to be aware of, but the roofing temperature
NON-issue was completely off the wall! )
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cmkavala
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Matt Phelps
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| 07/18/2009 10:44 AM |
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Hello Cathy,
Well this certainly turned into a lively discussion! I am from Texas where the International Residential Code (IRC) is the law of the land (so to speak). The IRC, in chapters nine and ten address the roofing requirements for shingle roof coverings, which includes all products made from modified bitumen (kind of like asphalt). Most ice and water shield products contain modified bitumen.
The issue here is that since SIP roofs are not vented then mod. bit. products can not be attached directly to the SIP and maintain compliance with the IRC. As an licensed professional engineer and Texas Department of Insurance appointed engineer (wind storm inspector), I have inspected 1,000s of roofs since hurricane Ike and have found that those components that are typically used on composition shingle roofs (this includes felt, and ice/water shields) will not comply with the IRC on SIP roofs. I have contacted one manufacture (GAF/Elk) who will go so far to say that if you use their mod. bit. products on non-vented roofs (SIPs) they will void the warranty!
So, you may want to reconsider the ice and water shield (if it is one that contains mod. bit.), not sure, but I think all of them do. A good alternative is a product made by Dupont that is like Tyveck, but for roofs. Dupont makes a version of Tyveck that has a crinkled appearance that will create a dead air space that may be worthy of your time and consideration.
Best of luck, if you would like to contact me off list, please use my email below,
Matt B. Phelps, P.E.
SIP Engineering & Testing, LLC
mphelps@apec-llc.com |
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sipfreak
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| 07/18/2009 11:05 AM |
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| if you have the ice and water shield, it becomes the secondary water barrier. Who cares if the shingle warranty becomes void anyway. Did you ever try to collect on one ? LOL |
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Matt Phelps
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| 07/18/2009 12:02 PM |
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Well you make a good point, I do not know of anyone having ever collected on a shingle warranty, BTW the voided warranty I referred to would include all mod. bit. products which would include the ice/water shield.
Of much more importance is non-compliance with the IRC.
Here in Texas, in the 14 coastal counties and certain portions of Harris County (Houston) in order to obtain windstorm coverage as a portion of the homeowners policy part A (dwellings and dwelling extensions) all structures SHALL be inspected (and pass) inspections by TDI appointed engineers (or TDI inspectors under certain conditions) for roofs, windows, siding, and external doors for compliance with the Texas Version of the 2006 IRC and be constructed with products approved by TDI or in compliance with ASTM D3161 class F or other TDI approved test method. Kind of a wordy way of saying, that if the structure is not compliant with the IRC it will not be insurable. Ouch!
Good luck,
Matt |
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cmkavala
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| 07/18/2009 12:14 PM |
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Matt;
It has been getting thru the building departments (Texas too)like this:
Metal based SIPs are the water proof component
any additional membrane such as ice and water sheild is a bonus
then the finished roof wether it be shingles or metal is mearly a decorative finish.
you basically have 3 layers of protection |
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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Matt Phelps
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| 07/18/2009 2:15 PM |
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Hi Chris,
I am sure you are right that this is slipping past local, or municipal building departments; however, and let me be clear about this. The Texas Department of Insurance (TDI) WILL NOT issue a windstorm certification (WPI-8) for any mod. bit. products on a non-vented roof. No exception. I understand and appreciate your comments; however, if I, or any other appointed engineer approved such a roofing system in the windstorm zones, we would lose our license. I have discussed this issue at length with TDI and they have affirmed, if it is not built in compliance with the IRC, they will not provide windstorm certification, and the structure will not be insurable for windstorm coverage.
Matt |
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cmkavala
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| 07/18/2009 2:55 PM |
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Matt;
If I understand correctly ..... the TDI would allow a SIP if its intended use was a finished roof panel. But would not approve the shingle installation as a cosmetic veneer? |
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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Matt Phelps
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| 07/18/2009 7:01 PM |
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Chris,
Only if the SIP has a TDI product evaluation report may the SIP (roof or wall) receive windstorm certification. My testing company performers this service for SIP manufactures, I have worked with TDI regarding test results and submission protocol for SIPs.
As to the shingles, yes that is correct. The basis is that shingles, which are covered by homeowners policy's, must be installed in compliance with the manufactures installation instructions and the IRC (vented roof). The shingles may be a cosmetic veneer to you, but to an insurance company they are a functional liability, and if they become damaged, (such as a hail or wind storm) the carrier will be expected to pay for their replacement, in turn the carrier is entitled to confirmation that the shingles were installed in compliance with the manufactures installation instructions and compliance with the IRC (both of witch require a vented roof). The rational for this is that the roof exterior gets too hot if it is not vented and the shingles will not perform as the manufacture intended, causing the shingle, or any other mod. bit. components to fail under less sever conditions (lower wind speeds) than they otherwise would.
This is not just an issue about construction, but also about insurance policy terms. The role of the TDI engineering section (among other issues) is to confirm that construction that is certified for windstorm coverage is in compliance with the IRC.
Matt B. Phelps, P.E.
SIP Engineering & Testing, LLC
mphelps@apec-llc.com
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tmsu
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| 07/18/2009 7:02 PM |
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Posted By Matt Phelps on 07/18/2009 2:15 PM
Hi Chris,
I am sure you are right that this is slipping past local, or municipal building departments; however, and let me be clear about this. The Texas Department of Insurance (TDI) WILL NOT issue a windstorm certification (WPI-8) for any mod. bit. products on a non-vented roof. No exception. I understand and appreciate your comments; however, if I, or any other appointed engineer approved such a roofing system in the windstorm zones, we would lose our license. I have discussed this issue at length with TDI and they have affirmed, if it is not built in compliance with the IRC, they will not provide windstorm certification, and the structure will not be insurable for windstorm coverage.
Matt
While I have no doubts to the truth of what you post, it nonetheless, makes no practical sense as it relates to a sealed and conditioned attic space utilizing SIPs for the roofing substrate. There is absolutely NO problem using a SIP panel then felt then a standing seam metal roof. None. As I wrote, I have no doubt it wouldn't pass code in a variety of areas, but that is more due to the lack of understanding than practicality. Sorry if that insults some on here but the facts lie with history of this method.
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wes
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| 07/18/2009 8:50 PM |
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Mr. Phelps,
I am a little confused by your posts about the venting requirements for shingled roofs. I checked my copy of the IRC, and can find nothing about a venting requirement for asphalt shingles, not in the roofing section concerning asphalt shingles(R905.2), nor in the roof ventilation sections on conditioned attic assemblies (R806.4).
Also, I understood that Elk brand shingles were one of the first companies to provide a full warranty on their products for use on SIPS roofs.
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Wes Shelby
Design Systems Group
Murray KY
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Matt Phelps
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| 07/18/2009 10:22 PM |
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Mr. Shelby,
I stand corrected. The IRC requirement for vented roofs in not in chapter nine, it is located in chapter eight. Specifically it is found in section R806 Roof Ventilation (this is page 286 in the 2006 version. This section R806.1 begins VENTILATION REQUIRED. You may wish to review this section as I note you do cite section R806.4. I read in section R806.4 that conditioned spaces do not have a venting requirement if four conditions are meet; however, I have not inspected any structures that complied with these requirements. To suggest that venting is not required by this code is just wrong. I do not know of any inspector that would agree with your assertion.
At the Worley Catastrophe Services annual conference a few months ago (I am a licensed insurance adjuster) GAF/Elk presented a program on shingle damage testing results. At this meeting I asked about the GAF/Elk warranty on SIP roof structures. The GAF/Elk instructor was not sure and had to confer with his office and reported to the class that GAF/Elk had researched the use of their products on unvented roofs and has concluded that they would not warrant an installation of their product on unvented roofs such as SIPs. I have contacted GAF/Elk about the warranty issue and will report to this forum.
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wes
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| 07/19/2009 8:36 AM |
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R806.1 and R806.4 would seem to carry the same weight within the code.
So, for you to base your entire argument on R806.1 and ignore R806.4 would seem a little narrow minded, don't you think. Just because you have never seen a roof that conforms to 806.4 doesn't mean that they don't exist.
The point is, you can build an unvented roof and meet IRC. |
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Wes Shelby
Design Systems Group
Murray KY
wandr@ainweb.net |
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cmkavala
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| 07/19/2009 11:26 AM |
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Matt;
I read R806.4 and it refers to conditioned attic space.
Typically any of the homes I build do not have an attic space, as the underside of the panel is drywalled and is conditioned room space.
I think this is a mis-interpretaion of the intent of the code and does not apply.
Shingles such as ELK (now GAF) are approved for unvented roof systems.
I simply don't see the problem from a code, TDI, or manufacturer's warranty standpoint
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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Matt Phelps
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| 07/19/2009 11:28 AM |
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Mr. Shelby,
I must consede you make a valid point, and I am by no means the end all to any topic; however, the issue remains. |
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