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We are having a new home constructed for us and our contractor uses corabond for ceilings and walls. We recently attended a Home Show and the Icynene product seemed to us to be the superior product. Total square footage will be 2215, including aprox. 600sq ft half story. The majority of our ceilings are vaulted. Our walls will be six inches, and our trusses will have to be site built. What, in your opinion, is the optimal insulating material? (We have to use propane for our heating source)
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What is "corabond"?
*Dan,Thanks for the e-mail. I am not at all familiar with "Corabond" or it's performance. Icynene is an impressive product. However, you should know that the people promoting products at Home shows are there to sell you. I am not going to say that they are unscrupulous but you need to understand where they are comming from. They want you to buy their product and they can be very persuasive.On the other hand, your builder has most likely been dealing with insulation subs in your area for some time. For whatever reason, he likes "Corabond." Kalamazoo is an area where reputable builders can not skimp on insulation so I suspect "Corabond" is a reliable and cost effective product.The fact that "Corabond" is a spray on rigid foam indicates (to me) it is an upgrade over fiberglass batts.One issue bothers me and you may want to discuss it with your builder. In your post you stated you will have 6" walls which I take to mean 2"x6" studs. In your e-mail you stated "Corabond" is sprayed on 2" thick. Why are you building 6" walls if your insulation is 2" thick? I suggest you talk to your builder about Icynene. He should not object to using it if you insist. However, Icynene may cost more than "Corabond" and that additional cost, along with the costs associated with any schedule interuptions will be your responsibility. It may pay you to talk directly with the insulation sub. You may come away as sold on "Corabond" as you were on Icynene.Your ultimate decision should be based on the initial costs of the insulation packages and their relative performance over time. A more expensive insulation package may pay for itself in reduced heating costs. These are difficult numbers for someone like you or me to work out but your insulation and HVAC contractors should be able to help. I am not a big fan of heating with propane. The only reason people use it is because natural gas is not available. Propane and natural gas are market commodities and subject to the kind of price fluxuations we are seeing in gasoline right now. Of the two, propane is the most volitile. To me, this favors spending more up front on insulation. Over the long haul both propane and, to a lesser extent, are more expensive than the only practical alternative - ground source heat pumps.When we built our current home we considered Icynene but ultimately went with wet spray cellulose in the walls and dry spray in the ceilings. The job was done by a subsidiary of the compay that built and installed our ground source heat pump. We are very pleased with the performance of both systems.Good luck,Steve Hansen
*As an Icynene dealer, maybe I can separate the two products. I believe Corabond (sp) is a rigid foam. Being a hard foam it would possibly have the same characteristics as other rigid products. Cracking, popping loose from the substrate or shrinkage. I'm not familiar with the product, so please do your homework. Icynene is a flexible foam. It may have a lower R-value per inch than Corabond. We usually recommend 3-1/2" of Icynene. Being flexible, it will move with the building. No cracks, no shrinkage. Icynene will not break down when exposed to light or water. I'm not sure about Corabond. If Corabond offgasses, you may be getting into a health issue, as well. Ask questions. Go with the product that gives you the answers you're looking for. Good luck.
*As a generalization, Icynene or cellulose are better choices for enclosed cavities and Corabond (or other polyurathane foams) are better when sprayed into open cavitys. Of course I am ignoring $/R/Sq.Ft. I have used all three plus my very last choice of fiberglass.Ron
*Corabond, I recall, is a proprietary version of closed-cell polyurethane, probably R7/inch -- if you want to know for sure, ask the mfr. It is doubtless quite expensive, so they only put a 2" skim coat in to get the Code minimum sidewall R-value. Don't recall what the blowing agent is -- the word is to avoid formaldehyde offgassing. Icynene is half the R/inch, so it needs to be twice as thick; it is supposed to stink for a brief time after installation. Cellulose would be the cheapest option, same R as Icynene, and air-sealing. But what your builder is familiar with is important. Check how much thought went into their choice -- many builders don't worry about thermal performance a whole lot, after all they won't be around to pay the heating/cooling bills. By far, air sealing is the most important issue -- don't let the house act as a big chjimney, pumping warm air out the top and sucking cold air in the bottom.
*In discussion concerning polyurethane and partially insulating a cavity assembly, the following approach offers a interesting mix. The skim-coat polyurethane approach uses a thin (0.75-1.5 inch) layering of polyurethane (less prone to gap or crack than thicker applications) with a subsequent layer of fibrous insulation to complete the cavity fill. This offers an opportunity to only use the costly insulation to provide an insulating, airsealing, vapor diffusion retarding layer while using the lower cost fibrous insulation for the bulk of the cavity fill. "What, in your opinion, is the optimal insulating material?" Except for "it depends," I don't have a one-insulation-fits-all answer for you. Dense-pack cellulose has become the insulation of choice of many energy-efficient homebuilders. I know some builders who traditionally used cellulose and now foam in polyurethane too. Rice Krispies will insulate if the assembly is designed appropriately to handle them.If you concentrate on airtightness with breathable construction and recommended (or above) insulation levels, your home should perform effectively. Remember to use sealed combustion HVAC, domestic hot water heating, etc., however, to limit backdrafting and other problems. The energy-efficient home is a system of elements that, like a vehicle, has to be well-designed to perform at its intended high level.Best wishes!Cameron
*Note that the Rice Krispies must first be treated with insecticide and, perhaps, fire retardant?
*Don't forget the milk! And...I like a touch of sugar....Snap! Crackle! Pop!Rich Beckman
*Dear Sue,As an Icynene dealer I have a question for you. Because the lumber used to build homes with these days has a higher moisture content. I wonder if the Icynene retains its bond with the lumber as it dries.Thank you. Greg.
Hi Sue,
I will be having Icynene installed in my rafter bays (plate to ridge). The agreement says R-30, but I don't recall how deep that is suppose to be. How deep is R-30?
Also, given an R-30 for Connecticut, have you ever seen ice dam issues?
Many thanks in advance.
Woodside
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We are having a new home constructed for us and our contractor uses corabond for ceilings and walls. We recently attended a Home Show and the Icynene product seemed to us to be the superior product. Total square footage will be 2215, including aprox. 600sq ft half story. The majority of our ceilings are vaulted. Our walls will be six inches, and our trusses will have to be site built. What, in your opinion, is the optimal insulating material? (We have to use propane for our heating source)