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gregory beere Posted: Aug 31, 2006 12:46 PM	Roof Leak I am new to this forum so please let me know if there is a place I can locate this info. I am building a new home with a standard gabled roof truss package. The sheathing is 5/8" plywood. We taped the joints in the sheathing with window peal and stick flashing. We want to use foam insulation. Icynene or Polyurethane? We are leaning to Poly. I can not seem to get a strait answer on what happens if the roof has a leak. I can not be the first person with this question. Thanks in advance for any answers.
John Shockney Posted: Aug 31, 2006 02:45 PM	First of all, all SPF is Polyurethane based I think the diferince you are talking about is open cell (soft)foam or closed cell (rigid) foam. Icynene is a soft open cell foam that will let water pass through it, there are several manufactures of this type of foam and it is the only type of foam with code aproval to be installed on the underside of the roof. The thinking behind this is that if closed cell is used and the roof leaks the water would be traped in the sheating giving no indication of a roof leak. By the time you found that the roof was leaking the sheating and rafters would have to be replaced. Hope this helps Thanks Airpro
gregory beere Posted: Aug 31, 2006 07:39 PM	You are right. I just got a diagram from the closed cell foam people and they depend on the water finding its way to a seam in the sheathing and down a truss. The problem is we taped all the seams. It sounds like to me the water will stay in the roof and wood and rot the sheathing. I think we are going to have to go with open cell unless someone can tell me something otherwise.
John Shockney Posted: Aug 31, 2006 11:24 PM	If they have a diagram showing water finding the seams and flowing out. I can't undestand that happening because the SPF will find all those seams, flow into them, and expand, compleatly sealing those seams and cracks up to the tar-paper. Sounds like a salesman's answer. Was his lips moving? Thanks Airpro
Gerry Wagoner Posted: Sep 03, 2006 10:14 AM	NCFI has approval of Insulstar rigid foam sprayed as an unvented roof material (insulation envelope). The easy answer is to make sure your roof doesn't leak. Don't rely upon the insulation for the waterproofer. gcw
Dave Strnad Posted: Sep 03, 2006 11:26 AM	I agree make sure the roof doesn't leak. I don't know about you but I would rather have a product that is water proof over a giant sponge in my attic. I think I am going to have to start spraying open cell to compete. The local guys are claiming an R- 38 for 6 inches. I won't say the name I****** but they are marketing there product as something other than open cell. I just ended up in an argument with a customer that was told that it wasn't open cell, that it was something different. Also that it has an r-value of R-38 for 6 inches and wanted me to spray closed cell, which actually does have an r-38 for the same price. I was actually cheaper on my open cell bid. I gave them the website address and told them to look into it themselves. I really wish that everyone in this business would just give the facts instead of trying to mislead people. I think there is a place for both open and closed cell. This product sells itself when the facts are presented. I usually bid both, but haven't sprayed open cell yet.
SprayFoamSupply.com Posted: Sep 03, 2006 09:44 PM	I have started quoting 2 inches of closed to adress the vapor retarder with 7 inches of open in the roof to make my bids more competitive. George
gregory beere Posted: Sep 04, 2006 09:39 AM	So this is where I am.....We taped the seams. so the only place water can run through the roof is nail holes. It would have to be a pretty big leak to find it's way down the sheathing, through a nail hole, through the insulation, saturate the drywall eough to see the leak. The leak could go on for years. The fear is that the sheathing will rot out. The closed cell people say the water will find a path. If it doesn't crack away from the framing memeber where are the cracks. The open cell guys are saying that water will run right through it. Does open cell foam absorb water? Does the skin keep water out. I know that closed cell has a higher R value. I know that closed cell adds structural rigidity. My BIG QUESTION is, can either product guarantee that their product will not trap water if the rood leaks causing the sheathing to rot?
Dave Strnad Posted: Sep 04, 2006 06:05 PM	What type of roofing are you using? Is it succeptable to leaks? Techinchly water will just run right through open cell, however on each side of the foam a skin forms which can hold water. Probally worse case with open cell is a very large area of open cell becomes saturated with water. Could cut skin off, fix leak and let dry out or remove saturated foam. Closed cell should seal out the water, water will not go into closed cell. Probally would still get through eventually along a truss or pin hole. This is a tough one, but realistically even without spray foam small leaks can go undetected and eventually cause rotting. Unless it is a major leak it takes a long time for you to notice. Personally I would make sure you hire a a good roofer. Also most leaks are around penertrations through the roof. You could always put flashings around them so the foam is not sealed to your vent pipes. etc.
John Shockney Posted: Sep 04, 2006 07:42 PM	Ok, Greg Are you totaly confused yet?? This debate is on going one supplier says this, another says that. And no one can guarantee anything beyond their product for falure, if the roof leaks and the insulation traps water the insulation manufacture is going to blame the roofing company and so on. My best answer is based on economics if your house has room for the required R-value that you desire or is required by code spray open cell foam. I spray 10 inches or R-38 of open cell foam, you need 5.5 inches of closed cell to get the same R-value at a per inch cost of 3 times as much. 10 inches open cell foam $3.00 per sqft 5.5 inches closed cell foam $4.95 per sqft The only other factor is the added structural rigidity, are you in a huricane zone? Hope this helps Airpro
gregory beere Posted: Sep 04, 2006 08:45 PM	It seems I am getting closer to figuring this thing out. The shingles are 50 year 110 mph rated architectural shingles. We are using a good roofer. You are correct about slow leaks being hard to detect. We are in northeast Florida. Hurricane central.... We will install the roof and wait for a rain storm, and watch for leaks. Once we are sure the new roof is not leaking, we will apply the foam. Now I have a little monkey wrench in my pocket. The closed cell foam is $2000.00 less than the open cell guys. This is a 3200 sq. ft. two story house with a horse stable. Now I need to ask them what thickness they are spraying. I kind of have an apples and oranges thing going on here. By the way, thanks for everyone’s input, this site has been very helpful.
gregory beere Posted: Sep 05, 2006 05:04 PM	OK.....More info. The closed cell guys are spraying 3.5" which they say is = to R7 per inch, but it has an efficiency rate of 92%. They are saying that this gives me the equivalent of a R63.7 for the 3.5". They are also saying that the open cell has an efficiency rate of 44% and R3.5 per inch, but because of the lower efficiency rate, the recognized R value is 13.72 for the 3.5" sprayed. To cap it off, they say this info comes from the US Dept of Energy, National Laboratory System, Science and Technology Info. Can anyone tell me how to find this DOE document? Can anyone disprove these statements? Thanks in advance....
Gerry Wagoner Posted: Sep 06, 2006 06:45 PM	Try Roger Morrison at NCFI. Very bright individual. olger
Posted: Sep 07, 2006 01:20 PM	I would ask these guys to provide proof to you from a third party independent testing facility. I have heard these same claims before but have yet to see anything in writing from an unbiased source. Having said that, I still believe that, in the end, either type of foam (properly installed and at proper depths) will provide you with excellent insulation value and will keep your energy bills as low as possible. We spray about 80% of our jobs using open cell and have not had any problems on a roof deck, water leaks or otherwise. I have been in a house that we finished the roof deck on and a heavy rain came down (south Alabama storm). After about 10 minutes there was one area that water was dripping through the foam (6" open cell). After the rain stopped I went on top with the homeowner and we found the source of the leak about 10" above the area it came through. The next day the foam was completely dried out. However, the argument about roof leaks is plausible but weak. Thermal insulating value is what you are looking for and 3" of closed cell or 5.5" of open cell will give you what you want. And yes, there is an abundance of data to back up this claim. If these guys provide you with documented evidence concerning the R63.7 claim, please post it. I'll hold my breath.
Tony Huber Posted: Sep 07, 2006 01:52 PM	Hey all, new to forum and this this type of product. The info I have is not to use a closed cell foam on a roof system -also known as a 2# foam and is used mainly in walk in coolers because it is a vapor barrier- because it will definitely cause the sheathing and framing members to rot reguardless of a leak here in FLA. The moisture/humidity will be trapped between the foam and the roofing membrane if it finds its way in
gregory beere Posted: Sep 07, 2006 06:30 PM	Now I have guys throwing claims out on this forum with no proof. How do I know you are not bidding on my job with open cell foam? Why is it so hard to get the facts. How can you say not to use closed cell 2# foam in Florida. No one else in the country has high humidity? (Roof shingles shed water, they don't seal it out. If moister gets in, it can get out....in my uneducated opinion) Please give me a link to this info. What are the K values of open and closed cell foam. If open cell has a higher perm rating it is definately loosing R value rating. It sounds like both have +'s and -'s. If I had to choose right now, I would use closed cell and take my chances with any roof leak. Florida has these big storms that can tear your roof off. I will go with the higher insulation value and structural stability. p.s. If anyone is able to find any facts (Not already mentioned) about this stuff, please let me know.
Gerry Wagoner Posted: Sep 08, 2006 07:06 PM	Tony: Your claim, however well-meaning is not accurate at all. Either one of the foam "flavors" will work well. How do I know? We have been spraying foam for 23-years and have hundreds of case histories we can provide. Both are winners. This whole debate is a waste of energy and foam saves energy. :). gcw
John Shockney Posted: Sep 11, 2006 11:44 PM	Now I know you are totaly confused!!! I did some checking on the net and the only thing that I could find is about all spray foam insulation:.... Their ability to fill even the smallest cavities gives them twice the R-value per inch than traditional batt insulation. <<<<this link is where I found this info!!! Now for the math these "pro's" gave you 3.5 inches x r7 = r24.5 they say it's = to r63.7 or 260% of it's manufactures rating not 92%. And open cell is 3.5 inches x r3.8 = 13.3 they say it's = to r13.72 or 103% of it's manufactures rating not 44%. My only other question is equivalent to what? for their comparisons. I'll stop complaning about their trying to over sell their product and say that due to your location I would recomend the closed cell foam and the 3.5 to 4 inches should be ok based on the eere comsumers guide. Hope this helps you. Thanks for a good question and a good debate. Airpro
Aaron Scurlock Posted: Sep 12, 2006 07:20 AM	I am a roofer. I install roofs. If I were you, I would have a tile roof installed in low rise, then foam the underside of the deck. The low rise will keep the tiles from blowing off in a hurricane. These are the best-performing roofs down that way (next to SPF flat decks adhered straight to the deck) for this purpose (hurricanes). A good roofer will be able to keep you dry. A good foamer will keep you cool. I do not see how, if the roof is intact and properly installed, that the foam would cause the roof deck to rot. The open cell seems to be the best deal....if you have a good roofer.
Posted: Sep 12, 2006 09:25 AM	Greg, I don't blame you for being cynical. The endless debates, usually with unsubstantiated claims or just plain opinions, is very tiring. I am not a degreed engineer, chemical, structural or otherwise, but I am a licensed homebuilder and have close to 300 foam installs in the last 3 years. This does not make me any kind of "expert", but I have seen and studied enough to be confident in the ability of either type of foam to do the job you want. However, with your situation in FL and the potential for high wind conditions, I would lean as well in the direction of closed cell foam. I believe the desire for increased structural rigidity would outweigh the potential for moisture entrapment. Of course, using an impermeable roofing membrane instead of felt under the shingles would also be a good idea.