Metal Roof and Icynene Insulation

Guest User
8/11/2002
I am building a house and have installed a standing seam metal roof. While looking to insulate the house, I decided to use Icynene insulation on the roof. The insulation company told me that I would not need to worry about ventilating my attic with this type of insulation. Does this sound right? I did not install vents due to the roof manufacturer saying the installation of this type of roof automatically vented itself. I am confused as to what to do!
Todd Miller
Isaiah Industries, Inc.
8/11/2002
There is quite a bit of info on the internet about icynene. Also, ultimately, I think you should consult the insulation manufacturer. The theory, which makes sense and is gaining acceptance, is to use icynene to insulate roofs and walls and even floors. By using this moisture-resistant insulation right against the outside surfaces of the building envelope, you should not hit dewpoint at those places, meaning that condensation will not occur. In my opinion, it is highly critical that the icynene be well-installed and not have any voids or gaps in it. Gaps in it could allow moisture to sneak in between it and the exterior sheating and that could lead to troubles. Also, the icynene, if it is used beneath the roof-decking, should also be used in the walls. I'd be very concerned about using it only on the roof. For home comfort, you may need to control moisture sources inside the home. Letting indoor humidity go above 40 - 50% could be less than healthy and could very well lead to mold accumulating somewhere. Unless they are doing something different than the standard icynene application I am familiar with, it really would not be appropriate to say it is self-venting. It really doesn't allow moisture to escape the home. Again, I urge you to contact the insulation manufacturer and make sure things have been done properly. Use of icynene might necessitate some change in your HVAC system. Also, use of icynene beneath roof decks will, according to some people, shorten the lives of standard roofing shingles. It will not, however, shorten the life of metal roofing.
Guest User
2/14/2008
Todd, I just left you a voicemail and then I found this message from several years ago. I am building a new riverfront home in east central FL with standing seem metal. The insulation I want to use is either Icynene or an alternative called Agribalance by Demilac (open cell foam). One roofing contractor told me the metal roof needs to be installed onto furring strips to create air space for condensation above the decking otherwise the decking will rot from the dewpoint occurring within the plywood. The other contractors and foam insulation people say thats not necessary, they have had no problems using both products and further that installing the roof on furring strips won't pass wind requirements. Your thoughts would be great.
Todd Miller
Isaiah Industries, Inc.
2/15/2008
I do not think that the airspace is necessary at all if you are using icynene. I am unfamiliar with Agribalance. This point is perhaps moot now but as for the comment that putting metal roofing on battens will hurt its wind resistance ...that should not be the case with most products. However, keep in mind that not all metal roofing products can be installed on battens. I hope this helps.
Guest User
5/26/2008
I am also thinking of using this type of insulation. I have a cabin at 6800 feet elevation. We get quite a bit of snow. There is currently no insulation, except against knee wall. I can get in the knee wall area and spray the insulation up against the roof and into the cavity on the sloped roof, however I have a small section of flat ceiling. It kind of looks like this. http://www.paustian.org/bath.jpg I was debating about just spraying it on top of the ceiling by drilling holes, or if I needed to I have enough room to get into this area and spray right up against the roof. I am thinking maybe it would be better to do that.
Todd Miller
Isaiah Industries, Inc.
5/29/2008
You definitely want the insulation to be complete and full over the entire surface.
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