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It works fine in Florida so far. We don't have temperature extremes and condensation/freeze problems. The theory here is the attics are insulated but unventilated. Don't know what's gonna happen when roof leaks rot out the plywood roof sheathing and it's glued in place.
It works fine in Florida so far. We don't have temperature extremes and condensation/freeze problems. The theory here is the attics are insulated but unventilated. Don't know what's gonna happen when roof leaks rot out the plywood roof sheathing and it's glued in place.
....this stuff isn't sprayed on the roof sheathing, it's generally used on walls or the underside of floors. If one were to use it in the attic one would spray the attic floor.
This stuff if you sprayed it on a wooden structure that is leaning on a 45° angle, the hardened foam would make that structure rock solid! If that structure were to fall down at a later date it would be falling down as a one piece structure and could be restood back to it's former glory of a structure leaning on a 45° angle.
Per inch of thickness, I don't know of a better insulator........but the cost is definitely high....but it also doubles as an excellent vapor barrier and mositure barrier.
I recently had it done in a home I built and I am astounded at how good it is. I had all the exterior walls done as well as the roof. The folks that did mine were convinced there was no point in letting the attic get hot and then soak the heat into the dwelling, so they sprayed the underside of the roof sheeting and the rafters. I had the roof sheeted with Tech-Shield, which is not supposed to have anything applied to it, but I have not seen any negative effects from doing so. If I had it to do over, I would not have done the Tech-Shield, because it really hurts cell phone reception and I don't think it was needed with the Icynene. I did the walls at a 4 inch nominal thickness and the roof at 6"
The attic is sealed, so there are no eve or roof vents. You can be in the attic at mid day and it is not much different than being in the house. The place is amazingly quiet. You don't realize how much noise comes in through eve vents and then right down through the light fixtures. It is strange to see cars drive by, but you don't hear 'em. The stuff has only been in place for about a year, but so far, I am 100 percent sold on it.
Thanks guy's. I'm doing some work for a regular client and he asked me to check out his attic for insulation. I had my insulator come out to price blown-in and he suggested the Icynene. I've read a few horror stories but I'm told that those were "copy cats" of Icynene.
There are many "pro's" to it.
FWIW there is a local builder here spraying just an inch or so onto the sheathing then he uses FG. Foam keeps the drafts out and we all know about FG. I'm wondering if using dense pac would be a better option vs FG???
__________________ 2003 Boston Whaler 255 Conquest w/ twin 200 HPDI's
I've never been a racist. I don't like the white half either.
FWIW there is a local builder here spraying just an inch or so onto the sheathing then he uses FG. Foam keeps the drafts out and we all know about FG. I'm wondering if using dense pac would be a better option vs FG???
It depends on where he plans on putting the foam. Closed cell foam put under the roof sheathing will more than likely melt your shingles since none of the heat can transfer through the foam. We used open cell throughout our attic space and absolutely swear by the stuff. Here are some pics of the job we had done last year. The pics with the temp gauge show the outside and inside temps. Outside the temp was 92 degrees which normally translated into an attic temp well past 110 degrees.....notice the temp was in the low 80's with the icynene.
The trick is to completely seal the space above your house, including the soffit vents. We didn't do it but some folks even have the foam cover the windows.
FWIW there is a local builder here spraying just an inch or so onto the sheathing then he uses FG. Foam keeps the drafts out and we all know about FG. I'm wondering if using dense pac would be a better option vs FG???
My insulation guy's here call that "flash & pak". The way I have them do my work is to spray the ceiling ( icynene ) and BIB the walls. I used to use cellouse but I now use this BIB system it will not settle like the cellouse and it is a form of chopped fiberglass which does need the insecticide that is in the cellouse. http://www.bibca.org/?page=BlowInBlanketSystem
Here you have to spray paint the icynene with fire retardant paint if it is exposed. Another thing about icynene is that it is soft, you can squeeze it in your hand sort of like a sponge so it will soak up water vs the closed cell which the water more or less runs through it, the closed cell being hard.
One other thing about the BIB system is that I get a R-23 on a 2x6 wall.
The folks that did mine were convinced there was no point in letting the attic get hot and then soak the heat into the dwelling, so they sprayed the underside of the roof sheeting and the rafters.
Hmmm, that's a brand new one on me.
- Were would the benefit be in doing the sheathing/ rafters? I can definitely see the benefit for the insulation company....more sq. ft to spray equates to more money/ profit.
- This site has had a few topic posts on shingle warrantee issues and I’ve had first hand warrantee issues myself to deal with. What "if" one’s shingles goes for a sh!t a third of the way through it’s rated life span? From my experience I don’t see a hope in hell the shingle manufacture will back their warrantee if a problem were to arise!
- No venting in the attic....hmmmmmm......that means stale stagnant air where air born bacteria can grow and thrive unchecked and un-flushed ......hmmmmm, that can’t be good! I guess that wouldn’t matter any if one sprayed the attic floor as well.....but if one sprayed the floor then why would one spray the sheathing??? If one didn’t spray foam the attic floor I still believe there would be some sort of convection happening even if one blew in Cellulose insulation. If there’s any form of convection happening then there is the possibilities of poor quality air in the living space....and that can’t be good!
As I said, this is all new to me.......I’m just thinking outloud.
You don't shoot the icynene between the living space and the attic....that would create a lot of very dead air space. By sealing the attic from the outside air, the attic air comes from the house and it can be recycled, albeit slowly.
Isn't this where the R2000 home design runs into problems....not enough exchange of air. Yes a R2000 home is suppose to have an HRV installed, but the home owner is supposed to change the filters regularly and run the system. Those that don't run into a problem with the air quality inside the house being much worse than the outside air.
Every shingle manufacturer I spoke to was requiring a cold roof system just for the reason you stated. At the time I was going to build a P&B home and use structural insulated panels for side walls and the roof system. They told me that if I didn't cold roof the house they were not going to honor the warranty on the shingles.
I didn't end up building that P&B and I'm still fighting with IKO for bad shingles over a cold roof anyway.
__________________ 2003 Boston Whaler 255 Conquest w/ twin 200 HPDI's
I've never been a racist. I don't like the white half either.
Isn't this where the R2000 home design runs into problems....not enough exchange of air. Yes a R2000 home is suppose to have an HRV installed, but the home owner is supposed to change the filters regularly and run the system. Those that don't run into a problem with the air quality inside the house being much worse than the outside air.
I don't know anything about this R2000 stuff you are talking about. What I do know is the space below my attic is over 50 years old and we don't have any problem with the air being exchanged throughout the day. The attic was built when we had an extensive renovation done 5 years ago.
I may be late to this discussion but I have a very simple question. What is the best bang for the buck if I want to add insulation to the attic space? So far, my answers are skewed to who I am talking to. In other words, the spray foam guy says spray foam, the guy who blows in insulation says blown in insulation, etc. Thanks for the help.
Icynene has been proven to be the most effective method of eliminating any means for outside air to infiltrate a space....the downside is it is more expensive to apply.
My buddies building contractor used it on their new home. He not only did the outside walls but they also did all of the interior walls. The house is so quite its not even funny
__________________ God doesn't bother me. His fan clubs do.
A mind is like a parachute, it only works when its open
We are HVAC contractors and I had my first experience with spray polyurathane foam in 1997. (Home and condo dream home I believe)
My home built in 2000 is a cracker style (cupola, garage below) has foam on underside of roof sheeting, exterior frame walls and trussed floor.
It also gives back all duct heat gain from ducts in hot attics.
Reduces the infiltration load on the a/c equipment.
Icynene is a Canadian company so it is also used in the cold weather climates. Check the Icynene folks and they will point you in the direction of qualified contractors.
There are obviously trade offs here. You need to look at the issue of condensation in the attic if you live in high humidity. Insulating the rafters may promote less condensation than insulating the ceiling, but any condensation can lead to mold and mildew problem. I've seen enough mold in attics to feel that leaving the attic un-insulated is not the cure to that problem.
If you are in an area where radon or some other fume/gas/toxin accumulation is a problem, having a sealed dwelling may not be the best choice. But I live in a hot and surprisingly dusty place with high utility costs. So, I'd rather my A/C units and ducting were running in an 85 degree area, rather than in 135 degrees. Likewise, the new house is a lot less dusty than the old house.
As long as I am paying to cool the air, I'd rather it stuck around as long as possible. I don't smoke or create unusual toxins in the house, so I feel there is less total "stuff" that would come through the house if it is sealed than if it were designed for air exchange.
The issue of any shingle damage does not apply because I have clay roof tile.
If you insulate the rafters as shown in the pics and as described above, why have the attic? Is it simply to have a place for wiring and HVAC or for ease of later modifications? Why not just use larger rafters with plenty of insulation and a vaulted ceiling with no attic?
__________________
"Of all tyrannies a tyranny sincerely exercised for the good
of its victim may be the most oppressive." ~ C.S.Lewis
Icynene Insulation 
....this stuff isn't sprayed on the roof sheathing, it's generally used on walls or the underside of floors. If one were to use it in the attic one would spray the attic floor.
