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Posted: Mar 31, 2010 07:01 AM	ice dams mason,, check out journal of light construction march 2010 pg 63 let me know what you think,,, this could be interesting,,, is the sky falling??? dude
mason Posted: Mar 31, 2010 08:43 AM	I don't have a copy of the magazine and could not download online. Can you email the article? After going online I did see some comments that suggested that the author has performed some calculations to conclude that unvented attics with SPF installed to the underside of a cathedral ceiling would cause ice damming under certain snow loads. I believe he says that 4 inches of snow would cause ice dammning with an R 30 of SPF. He further states that R 60 of SPF would allow ice damming with 8.5 inches of snow. This is his response to a reader who suggests that his conclusions were faulty I was intrigued by the following reader comments and response from the author Reader: "This assessment of vented versus non-vented attic assemblies is the most puzzling, inaccurate account of the scientific method I have ever seen. At no point was logic exercised or implemented. Prime Example: Figures 4 and 5 reveal that at 10 degrees F, 6' of snow piled on the roof deck will result in ice damning; however, if there is 4' of snow, it will result in no ice damning...really?! The diagram that shows conductive heat transfer permeating through the SPF to the roof deck makes no sense. He goes on the mention that R-30 or R-60 will result in the same ice damning results. I have seen this occurence on a handful of occasions. In each occasion, the SPF contractor did not ensure that the foam hit tightly to the top plate of the wall assembly (the soffitt). Notice Mr. Hoffman's infrared pictures do not focus on the soffitt - which is always the problem area. The delta-T that was present in this case study (30 to 50) was more than in acceptable parameters. Particularly if R-60 was applied. As a long time reader of JLC, I am confused as to why the editors would print an article that makes no sense. The non-vented attic assembly works and is being used all over the country with great success. If one example comes to light that fails, there must be a devil in the details. JP Author's response: "Johnny, This study demonstrates "that just like adding layers of clothing to your body, with each additional layer of insulation, your skin temperature will increase. Figure 4 explains that 6 inches of snow provides more insulation than 4 inches. In this case it is enough to cause melting at the snow to roof interface. The soffit at 10F will then refreeze the water dribbling down the shingles creating the ice dam. (Hence the problem area around the soffit vents as you pointed out). I think you missed the point of Figure 6. With an R value of 30 at 4F ice dam formation starts with only 4 inches of snow. For an R value of 60 at 10F, ice dam formation begins with 8.5 inches of snow. What this suggests is they would still have had problems had the roof had an R value of 60. Lastly, based on this study, I would not recommend using open cell foam for an unvented roof in areas receiving heavy snow. Interestingly, nor does the manufacturer. Hope my explanations help. Jeff" Mason's comments: The author's response to he reader shows that he is considering the snow to be a heavy insulative material, sufficient enough to allow the heat within the building to travel through the foam and melt the snow sitting on the roof substrate interface. Field history demonstrates that SPF stops ice damming in heavy snow areas unless as the reader suggests the applicator did not install the foam correctly or in the correct places. While I need to read the actual article to provide further comment and analysis, this appears to be another case of an engineer manipulating data for their own agenda (i.e. vented attics). It was also unclear in the comments whether the author was referring to closed or open cell SPF in his calculations (or both). OPen cell foam would require a vapor retarder element on the warm side of the insulation, and I don't know if the author included that design detail in his calculations. This comment from another reader seems appropriate "How can a roof be considered 'vented' when the ridge vent is buried under snow? Is a soffit vent alone enough to keep the sheathing cold in a conventional assembly (non-layered with baffles)?"
Posted: Mar 31, 2010 04:32 PM	mason,,i have a copy of the article from one of my foam friendly builders,, could you email me your fax and i will faxeamundo (fonzie lingo) it to you... i have remediated dozens of filterglass vented lid ice dam failures... with the big bucks these folks paid for sufficient closed cell foam to get the job done right, and to keep me in my comfort zone,,,i know that they would call me back if it didnt work well,,and work it does,,,now i am zone 5 not zone 7,,but we got more snow than the u.p. this year and in the year previous... i, like you,,, believe it is a case of makeing data say what you want it to...saw it all the time back in my orthopedic days,,, get me your fax bro and i will send it to you... dude
Posted: Mar 31, 2010 07:53 PM	What is an ice dam? Are they saying that because no heat is escaping that the snow turns to ice and holds to the roofdeck? Maybe I should have read the whole thing.... Forgive my A.D.D.
Posted: Apr 01, 2010 05:37 AM	a brief synopsis: an ice dam is the formation of a dam of ice down at the eve of a roof... common with inadequately insulated roof assemblys. ice dams need a snow covering on the roof to occur,,, the snow on the roof over the heated portion of the structure melts due to the inadequate thermal insulation allowing heat to pass thru the roof thus melting the snow,, the water runs down the roof till it gets to the eve,,which doesnt have the heated structure under it and is at outdoor temps,, thus it refreezes here at the eve,,,and forms a layer of ice,, now if this snow base is maintained on the roof (new or existing snow) and the melting process continues,,the water runs down and hits the ice at the eve and "backs up" refreezing and laying out more ice,,a little thicker each time due to the layer below it giving it a daming effect..obviously this water backing up can get under the shingles above,,cause they are desinged to allow drainage down hill,,not uphill water exposure,,it is not unusual to see dams 6-8" thick round here and we have some pix of them with icecicles hangin off the front all the way to the ground 9' below the eve,,, these pix are on ice dams i have fixed with the conditioned lid assembly,,bunches of em.. regarding this article,,it doesnt tell me how the sidewall is insulated,,it doesnt tell me how the truss heels were blocked and insulated.. we have condition lid assembly to ballooned framed houses with little to no insulation in the sidewalls and these girls are rolling heat right up thru the wall and truss assembly if proper blockout and thermal insulation isnt installed,,and they can continue to melt the snow right at this area.. i stuck a meter in the air i took the readings,, i dont care i made it say what i wanted to say then i made the customer pony up and pay burma shave kinda like the filterglass installer round here that is doing his own heers rateings you can make the numbers say what ever you want them to say,,, green builders indeed... a nod is as good as a wink to a blind horse..
Posted: Apr 01, 2010 06:54 AM	Thanks for the reply. I love learning something new. Certainly not something we deal with in Louisiana!
quentin Posted: Apr 01, 2010 09:11 AM	Can I move there too? I spent a tour in the Marines as a Cold Weather Specialist and HATE the cold anymore! LOL Nothing like being forced to camp out in -40 degree weather to change you opinion about winter being nice!
mason Posted: Apr 01, 2010 11:41 AM	foamdude, appreciate the article, I signed up for the magazine but evidentally it does not include the online version. Don't have fax, can you send an electronic versions. (print,scan,email) masonknowles@aol.com By the way, I had bad ice damming on my townhome in Northern Virginia the winter of 2002. It cost around $17,000 in damages (drywall, wood replacment, carpet, painting, etc.) The insurance company paid for it but said it would not do it again. So, I took out the 14 inches of blown in cellulose in the attic and put in 3.5 inches of closed cell foam. No ice damming since even with the 5 ft of snow they got this year. Seems like it should have not worked according to the author of the article.
Posted: Apr 01, 2010 12:12 PM	mason,, now im an technology challenged,, old grey headed fart,, but i will see if i can figure out how to scan it up and send it to ya,,rofl dude
quentin Posted: Apr 01, 2010 01:37 PM	Not home right now but I can do it for you. Just fax it to me a 937-306-2444 and I will then scan it when I hit the home office tonight and ship it to Mason in any format he likes. Sometimes being a geek with an IT background can be handy. LOL
mason Posted: Apr 02, 2010 09:25 AM	Appreciate it foamdude and Quentin. I have a combination printer, scanner and fax maching in my office, But I have never been able to get the fax maching portion of it to work. I have found it easier to scan documents and article, so then I can email them to folks who want them.
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Apr 03, 2010 09:30 AM	Dude, Can you also send me a copy of it. If it's easier your can fax it to me and I'l forward it along since it comes into my email. Thanks 585-502-4181
Posted: Apr 17, 2010 05:15 AM	mason, jim, et al: whats the take on this article??? one of my foamfreindly builders,, whom i sprayed 6 hot lids last year (7" CC) is scared,,,now we dont have any ice damns hangin on any of these,,or the other 20 or so from years previous,,but its "been launched into the world for scruitiny",,,and it is being scruitinized...and our highly eductated customers(which is why they pay for the upgrade to spf)know how to read,,know how to google,,and frequently make informed decisions... so i am hopeing for some "official rebutals" on this topic,,,aint herein nuthin from the spfa tech director,, i grabbed some numbers from my butt i scribbled em down and erased alot i wrote a paper and made it say what i want got my name in real big fonts burma shave
mason Posted: Apr 17, 2010 11:06 AM	I did not receive the article yet. Happy to address the claims as soon as it comes.
Circle-D Posted: Apr 17, 2010 10:05 PM	I am in the middle of a home show this weekend and was asked about that article from a prospect. I have not seen it so I could not give an informed opinion. Waiting for yours. Thanks
Posted: Apr 20, 2010 06:04 AM	hey jimster,,quentin... faxed you guys the article so you could forward to mason... did you not get the fax???... since the tech dir of the spfa wont return my calls with a "statement of position" i sure would like to hear the ex-tech directors take on this,,, yours as well roger... and any engineers or other "credible" experts.. 'dude
JohnPeters Posted: Apr 20, 2010 10:08 AM	I live in the North East and JLC is like gospel up here. Someone with a PHD needs to respond back to this article and dispute the authors findings. The article is full of crap. Completely illogical and when the data is assessed it does not equate to the answer the author came up with....at all. The charts are laughable. How can a delta of 2" of snow on a roof deck effect the accumulation of ice damning? Hey Coler! You're an engineer. Get on this! Johnny
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Apr 25, 2010 12:14 PM	I know! I read the article too. I've been keeping it low lately, after a stroke in Dec. But now, I'm almost back to normal and can put up a figt here and there. Other issues are taking my time though - like running a busniess! I'd be happy to pitch in and address issues like these if someone was willing to pay me to do so, but that offer hasn't happened yet! So, for now I'll watching from the sidelines and gathering info! Jim
Posted: Apr 25, 2010 12:53 PM	jimster,, uh,,you said you would forward the article to mason for me..which is why i sent it to you... do i have to pay you to do that??? and if so,,will you pay me for providing you the article??? (ps:never did hear back about the icc-es issue either,,,) rofl,,infact,,pmpilsh you 2 quentin,,,you both said you would forward,,and mason says he's still looking for it...wtf,,did you guys start wearin wingtips?? buisness integrity 101: do what you "say" your gonna do,,even if it costs you money...it has something to do with credibility, reputation, and integrity.... respectfully 'dude
Circle-D Posted: Apr 25, 2010 08:19 PM	send it to me 'dude.I'll print it off and hand deliver it to him on Wednesday or Thursday.
mason Posted: Apr 26, 2010 11:42 AM	I would like to thank all of the folks who regularly contribute to this forum. As Jim C noted, none of us gets paid to provide this service to the SPF community, but we do it to help out the industry. Please forward a copy of the article and I will do my best to respond to the specific allegations. masonknowles@aol.com Thanks,
mason Posted: Apr 26, 2010 11:47 AM	Jim, Sorry of to hear of your recent stroke. I am very glad to hear you are back close to normal. Send me a separate email to masonknowles@aol.com and let me know how you are doing.
JohnPeters Posted: Apr 29, 2010 07:09 PM	After reading through the article a couple more times I've formulated a different opinion. The installer is to blame here. The data is fuzy in areas and should be reassessed. But the bottom line is the contractor messed up. 1.) He had R-30 on the roof deck sheathing. He should have has R-49 (per the climate zone of the case study). 2.) In this particular climate zone a soffitt baffle is REQUIRED. Check out the article at JLC online: http://www.jlconline.com/cgi-bin/jlconline.storefront/4bda11fe0877ad7127180a32100a066d/Product/View/1003anic Lazy/uneducated installer makes bad press for foam. Surprise, surprise...
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Apr 30, 2010 09:12 PM	Ok, now it's time for me to chime in. I don't believe that the open cell foamis to blame. I recently ran across an open cell job which was done poorly and they had ice dams. This was with an unvented roof in upstate NY. The open cell was sprayed in to the cavities and some of the fiberglass still remained at the tops of the walls. So, we tooks it upon ourselves to take out the fiberglass from the tops of the walls and seal it in with more open cell. There were also openings within the open cell where it had shrunk back and left fissions in the foam and there were even whole bays which were missed. So, we're spending the next week or so repairing it. So, what's my point? Well, my point is open cell can be used jsut fine in upstate NY with cold winters and high HDDs. You had better just make sure that you'dve sealed it to the top of the wall and done a good job! I've seen many open cell foam jobs done with only 6" of open cell and no moisture accumulating in the foam. So, I would tend to agree that it was due to operator error, but not the error that you're talking about. I've done a number of jobs where we've been able to eliminate ice damming altogether with only 6" of open cell foam sprayed directly to the roof deck. When you understand the prinicples at hand, you can start to eliminate them from the causes. So, open ceel directly to the roof deck is fine and doesn't cause ice damms, it can correct ice dammswhen it's applied right!! Thanks, Jim
quentin Posted: May 01, 2010 06:16 PM	Sorry about that Dude, had a family emergency here and as a result missed the fax. I am setting up a different one since it means no more having to turn on and off the stupid answeriung machine or etc.
mason Posted: May 02, 2010 05:15 PM	I received the article from multiple sources. Thanks all> I am on a cruise this week with my wife and her family and away from my resources and network of trusted associates. I will address this article when I get back in the office next week. Although after reading the article, I must agree with others who have opined that the calculations must be screwed up.
Posted: May 06, 2010 09:16 PM	an engineer got paid some bucks what he said caused yuk yuk yuks it goes to show that money talks specially when the opinion sux burma shave :)~
Posted: May 19, 2010 06:12 AM	re: "I will address this article when I get back in the office next week." bump
mason Posted: May 19, 2010 04:46 PM	As I am not an engineer, I need to contact some of my associates to run the numbers. I would rather do this right and take a little time than to do it quick and have some inaccuracies that would just make the issue stronger.
mason Posted: May 20, 2010 10:01 AM	I have asked the assistance of Roger Morrison and Rick Duncan on analyzing the article and providing a response. But, there are a few things that are pretty glaring; 1. The author did not measure the roof deck temperature for his calculations, but instead measured the temperature of the walls of the garage, extrapolated the assumed R value of the foam based on inside and outside temperatures and then used that as a basis for calculations of the roof deck. I do not know why he did not just measure the temperature of the roof deck at the foam/deck interface. 2. I cannot see what R value he ascribes to the snow. My research shows that snow has an equivalent R value of 1 per inch. However, field measurments of snow and substrates in outside situations indicate that the snow/substrate interface remain at 32 degrees unless there is a heat source directly under the snow. So the question is, how much resistance to heat transer did the sprayfoam provide and how much of the snow melt was from the sun and how much from a roof deck temperature rising above freezing? I also want to look more closely at the roof/outside wall juncture. The details do not tell me how the applicator separated the outside and the inside of the soffit.
steven argus Posted: Apr 22, 2011 08:32 AM	Did we lay this issue to rest? Just had a potential customer refer me to the article in JLC. How can a great mag like JLC publish an article like this?
Posted: Apr 26, 2011 04:04 AM	how did we put it to rest...??? engineers are like lawyers,,,you can pay some of them to say whatever you want them to say... data can be,,and is,,manipulated to give the outcome needed for the study funded,,, dont believe everything your read,,specially on the beloved internet,,, anecdotally,,,we have remediated hundreds of ice dam problems,,,zone 5,,lots of snow,,ice,,rain,,all at once,,2x4 heels,,2x6 heels,,,conditioned lid assemblies,,non-vented,, to the peak,,, and what these consumers have paid$$ the general and the foamdude to remediate these ice dams we surely would have heard if the solution we offered didnt work,,,it did,,and it does,,quite handsomely(much like georgous goergous!!) there was much rebuttal in the jlc letters in the months following,,,all pretty much dispelling the bunk,,with the wingtipped geek standing by his claim the whole way,,,offering no real basis to substaitate his findings (such as the details mason eluded to),,, good luck,,, dude