Polyurethane Vs. Icynene Foam

Icynene foam is a relatively new type of foam when compared to polyurethane foam. Icynene foam is quite different from polyurethane foam, both in structure and in applications. While polyurethane based foam is used in foam roofing, Icynene is used more for insulation type applications. Polyurethane foam must be sprayed, while Icynene foam can be poured or sprayed. Icynene foam also uses an open cell structure, while polyurethane foam uses a closed cell structure. A case study example of an Icynene foam application will be provided after our discussion of some key differences between Polyurethane and Icynene foam.

icynene foam insulation
This image displays Icynene foam sprayed between a series of attic trusses. Effectively, icynene foam and polyurethane foam look nearly identical. However, polyurethane foam is 100% plastics based, while Icynene foam is 15% or more castor oil.

Polyurethane Foam Qualities

Polyurethane foam (commonly used in foam roofing and insulation) is based on petroleum byproducts, although there are ‘green’ versions, made partly from soy byproducts (instead of pure petroleum), which contain less HCFC and CFC gases. All types of sprayed polyurethane foam contain millions of tiny closed cells filled with HCFC or CFC gases. A blowing agent agitates the plastics causing the bubbles to form, and the material hardens within about one minute. Sprayed polyurethane foam is inherently water resistant due to its closed cell structure.

polyurethane foam samples
Polyurethane foams are known for qualities including: light weight, resiliency, and insulation quality.

Icynene Foam Qualities

Icynene foam is different because it is based on Castor oil (not plastics, also known as petroleum by-products) and it does not trap air in the cells. The resulting Icynene cells are open–which means no gases are trapped in the cells, so air-infiltration is possible. Due to air and vapor movement, Icynene foam does not insulate as well as closed cell foam. In contrast, closed cell foam completely traps vapors, completely blocking air migration–which enhances the insulating capacity of polyurethane foam. Icynene foam is more ideal for applications where some air or vapor must pass through the foam, while polyurethane foam completely blocks air and vapor transmission.

R-Value Comparison, Icynene Foam vs Polyurethane Foam

Although Icynene foam has lower R-Values than polyurethane foam (less thermal resistance and less insulation capacity), it still has valuable uses for insulation depending on the scenario. R-Value is a benchmark for insulation quality, and generally 1 inch of wood equates to an R-Value of 1. In contract one inch of medium density polyurethane foam (typically used for foam roofing as well as insulation) has an R-Value between 7 and 8. In other words, one inch of polyurethane foam is as effective an insulator as 7-8 inches of wood. In contrast, Icynene foam usually has R-Values of 3.6 to 4. The R-value of Icynene foam is lower than polyurethane foam due to the open cell structure. Aside from the base thermal resistance indicated by R-values, Icynene foam does not block vapor transmission like polyurethane so the actual insulation effectiveness is substantially less than the R-value discrepancy indicates.

Spray Foam is Manufactured on Site

The reason why both types of foam have R-Value ranges (e.g. polyurethane foam ranges from 7 to 8 normally) instead of specific R-Values is that spray foam is unique in that it is manufactured on site. Relative humidity, temperature, substrate, wind and other factors can all result in varying R-values. Generally, polyurethane foam must be sprayed in dry, warm conditions. Icynene foam however, has an advantage, because some formulations can be sprayed, even in moist, damp–even wet conditions (see the case study below). So although polyurethane foam must be sprayed in dry conditions, Icynene does not have this restriction due to the fact that there are water blown formulations of Icynene.

Icynene foam advantages

As already mentioned, Icynene can be sprayed in damp conditions (in an extreme situation). Icynene is also more flexible than polyurethane foam (rigid forms of polyurethane foam are used for both insulation and foam roofing). Icynene can also be ‘poured’ (not just sprayed). Sometimes installers drill holes in walls, then pour Icynene foam inside to fill otherwise impossible to insulate areas. Although Icynene is not impervious to air infiltration, it does trap air much more effectively than cellulose or fiberglass (despite the open cell structure of Icynene).

Icynene foam disadvantages

Icynene foam can soak up water just like fiberglass. Extreme care must be taken to avoid a situation where moisture is retained close to wood and other building and structural materials. Moisture can migrate through Icynene to condense on cold surfaces. This destroys insulating value.

Sprayed Polyurethane Foam’s two big advantages

Sprayed polyurethane foam is the only insulating material that does not soak up water or allow easy moisture vapor migration to pass through.

Sprayed polyurethane foam’s rigid nature increases structural rigidity and strength significantly.

More about Icynene foam

Icynene is a newer technology than polyurethane foam; polyurethane foam has been used both for foam roofing and insulation for decades. Icynene does have some advantages vs polyurethane foam; pouring, damn substrates, etc. However, all of these applications are for insulation and not for foam roofing applications. It is newer and not as well tested as polyurethane foam. And if installed incorrectly, there are reports of Icynene foam creating toxic odors. This is not cited as an inherent disadvantage, so much as an incorrect installation issue (new products often have installation issues–like solar panels did a few decades ago when usage exploded). Icynene is also more expensive than polyurethane foam, but perhaps more environmentally friendly (Castor oil vs petroleum base). Not to say that polyurethane foam roofing or insulation is not environmentally friendly, both are very green products. Icynene is just more environmentally friendly, but only applicable to insulation usages, due to the open cell structure. Icynene does have some very interesting application specific uses, see our case study below for a great example.

Icynene Foam Case Study

Boulineau’s Grocery store Myrtle Beach, South Carolina had some unique problems that required a creative insulation solution. A series of un-insulated walk-in freezers on their second floor had no insulation. This created a myriad of problems due to constant big drops of condensation dripping on to the floor, then eventually seeping through the floor and into ceiling tiles, creating ugly mold and discoloration right above the shopping area of the grocery store.

Boulineau’s Grocery Store: A Heavy Condensation Issue

Boulineau’s Grocery store needed insulation between the first and second floor, however, standard insulation such as fiberglass or cellulose was useless due to the fact that water was constantly seeping through. When the hot South Carolina air came into the store from the outside, the un-insulated freezers created a constant and perpetual heavy dew, which constantly dripped. The corrugated steel substrate was littered with patches of calcification and rust.

Ugly aesthetics aside, the constant dripping created a hazard for shoppers who might fall and slip. This created some potential liability issues for the store as well (no one likes getting sued). The owner of Boulineau’s found Spray-seal Insulation through their local yellow pages. Mark Winslow, a veteran of polyurethane foam insulation (20 years experience) was assigned to the job.

Sprayseal Insulation Assesses The Requirements

Mark Winslow of Sprayseal Insulation had to first assess the situation and determine what type of insulation could deal with the constant condensation issues in a permanent, cost effective way. He noted the constant condensation dripping from un-insulated freezer pipes, the ugly stains and customer slipping hazards as well as the size of the project. About 600 square feet total area would require insulation coverage. The store management did not allow Mark to build a scaffold because this would block shoppers from using the store. Also, the walk-in freezers could not be shut down (food was stored here)–which meant, the condensation would continue, even during the job. The 90% humidity of the Myrtle Beach South Carolina air also meant, that the condensation would continue around the walk-in freezers store even during installation.

Sprayseal Insulation: The Solution

In order to make the installation happen without a scaffold, only one ceiling tile would be removed at a time by the 1-man team. The prep work and subsequent insulation would be done from a top a 20 foot ladder with plastic draped below to trap any vapors, and allow customers to continue shopping, even during the installation. Since only 1 ceiling tile was removed at a time during installation, the remaining ceiling tiles would help catch any over-spray. A test spray confirmed that no odor would permeate the store so Winslow was given the go-ahead to start the job, while the store continued to remain open for business. The corrugated steel substrate between the second and first floor was prepared with Ospho, a rust inhibiting coating. With a brush, Mark Winslow applied Ospho to the corrugated steel ceiling deck. Any rust left on the steel was chemically altered by the Ospho changing it into iron phosphate, a hard black substance.

Mark Winslow chose water-based Icynene foam as the insulation product. Mark Winslow, a member of Icynene Dealer Network since 1997, was familiar with Icynene foam and he knew it would be effective for the unique requirements of the project. The water based Icynene solution used could be sprayed onto a damp substrate but still seal. The Icynene foam would also be flexible enough to stay firmly adhered despite heavy floor vibration due to both shoppers, and store employees. Winslow used an air gun to clear off most of the water, then sprayed the Icynene foam to a 3″ depth with just one pass at a time with a Gusmer H-2000 and a Probler Gun. Winslow stated he used only one full pass because this allowed the foam to adhere better than flashing, which is more effective with cold or oily substrates. Winslow wore transparent headgear and a full fresh air supply during the spray foam installation.

Why Water Based Icynene Spray Foam Was Used:

  • The insulation had to be applied to a wet surface–Icynene could adhere effectively to a damp surface.
  • The insulation had to be sprayed during store hours–Icynene is odor free and could be used safely during store hours.
  • The insulation had to be flexible enough to adhere despite second level floor and ceiling vibration and flexing: Icynene foam met this requirement as well.


The store is now cool and dry despite hot outdoor conditions, the Icynene foam effectively insulated the freezer pipes, preventing new condensation from forming. The Icynene foam also adhered to the substrate well, and is reported to still be functioning and effectively preventing condensation, even a few years after the installation. The Icynene foam effectively created a barrier between the most warm outdoor air and the cool walk in freezers.

19 thoughts on “Icynene Foam vs Polyurethane Foam”

  1. This type of new foam is really fascinating, I wonder if anyone who has tried it out can comment on what they think of it. I have read some complaints that the foam created a toxic odor for some people. However, I wonder if this is because it’s a new type of foam and maybe the contractor or manufacturer botched something in those cases. I only say this because most of the feedback I see for icynene foam is positive. What’s really amazing about this kind of foam is that it can actually be sprayed on to a wet surface. That’s really amazing-normal polyurethane foam wont stick at all on a wet surface–it really needs dry conditions. I’m guessing the castor oil or water base of icynene foam is allowing it to adhere completely in spite of wet conditions. I’m guessing once the foam cured new moisture stopped forming since the contractor reported good conditions when asked to update. I think if the foam had not completely insulated the refrigerators there would be wetness & mold. I heard icynene foam is supposed to be new or superior in some ways–but it honestly sounded inferior when I heard it was open cell (and had lower R-values). I think I understand better now that it’s both environmentally friendly and versatile for some applications–like this really unique condensation issue in the case study.

  2. I think it is strange to hear they have developed a foam that can actually stick to a wet surface. I wonder if anyone has had a personal experience with icynene foam insulation. While most people are very happy with it, I have heard some people complain about headaches. I just wonder if there’s any truth to this.

  3. Your blog keeps getting better and better! Your older articles are not as good as newer ones you have a lot more creativity and originality now. Keep it up!
    And according to this article, I totally agree with your opinion, but only this time! 🙂

  4. Icynene has a closed cell two pound foam, as well as open cell half pound foam. Both are great products. I have been in the same room as someone spaying Ld-c-50 open cell. I had no mask, and experienced no headach.

  5. I agree, this is a best article.A successful blog needs unique, useful content that interests the readers

  6. I have been installing foam insulation for 16 years. Both Icynene and Poly foams work very well at thermal insulation. I have successfully sprayed both, and they each have their good points. The only thing I would have to disagree with in this article, is that the open cell foams are still an air barrier, and will suffer no infiltration of outside air under normal circumstances. The porosity is extremely low, despite the “open cell” name. The closed cell foams have a much stronger odor problem, primarily because they use hydromethanes and propates, to inflate it. They are also extremely rigid and difficult to work with, but they insulate very well, and are more suitable for wet areas, or extremes in temperature, such as a walk in freezer, or such.
    Since they are really industrial foams, Closed / Poly foams are also more trick to work with because they cure very hot, and the operator must be cautious, or it can start a spontaneous combustion. Definitely not a do it yourself project. Cheers.

  7. I got this website from my friend who told me regarding this web site
    and at the moment this time I am browsing this web page and reading very informative content at
    this time.

  8. I’d appreciate an advice on using Icynene open-cell foam in the house – small area crawl space, and a small part of an attic bedroom (between the roof and wall). I’ve read a lot and it seems that the safety of this foam still hasn’t been fully cleared… My worries are of a mother, I don’t want my family to deal with any off gassing over a long-time period. Does anyone have a credible information on the likelihood of it? The EPA questions the safety of Icynene in a long-run, while some other websites claim the absolute safety after a 24-hour post-installation time… Any thoughts, please?

  9. I don’t know if this is a factor of the article being older and technology advanced, or what, but some of this isn’t correct. For example, you write about Polyurethane foam…

    “there are ‘green’ versions, made partly from soy byproducts (instead of pure petroleum), which contain less HCFC and CFC gases.”

    That’s partly true. For example the product we currently use in our spray foam insulation applications do contain up to 15% recycled/renewable content, but they also contain absolutely NO urea formaldahyde, NO CFC’s and NO HCFC’s.

    However I’m not sure if this is just because it’s a fairly new and advanced foam, and so might not have been available at the time of writing.

    Just thought I would point that out!

    1. Hello, I am shopping now to insulate my new home…well a new home built in 1995…my electric bill is telling me that I’m needing to insulate my attic. Can you tell me please the name of the green product you referenced here, because I have two children and I am very worried about the use of any toxic product, to the extent that I can do as much to prevent its use. Mostly the urea formaldahyde is of great concern to me. I would appreciate any direction or information you can give me. Thanks!

  10. I need to insulate the area defined by the top of my basement wall and the floor joist cavity around the exterior perimeter. We get mice. They bring in acorns! I’ve got cavities I can’t see to plug and hope the foam will do that. In one are there is a moisture problem. Other than that icynene sounds better and is 25% less. I’d love to save the money but suspect I should go with closed cell

  11. I want to insulate my loft with foam. Mainly to stop the heat getting in! I have a metal roof and I know temps reach 200F plus in the summer up there. Literally an oven! My garage also gets very hot and I am thinking of doing the inside of my garage door also as it faces westerly. Icynene sounds the way to go. Can any one comment or advise please.

  12. All previous comments very informative. I have only heard of icynene this month September 2017. It seems to have pros and cons so its horses for courses. It has a lower insulation value than PUR roughly 50% less. It can be applied to wet surfaces and PUR cant so that gives it advantages when insulating older properties. This product is now sold in Northern Ireland United Kingdom. One thing no one has mentioned is how flammable is it compared to PUR or PIR or styrene. Would it be safe to use if it burns readily. Rockwool mineral fibre insulation does not burn so how does it compare to that. Of course rockwool cannot be fitted into nooks and cranies.

  13. Is this foam fire retardant? One installer says he blocks the foam off of recessed lights or electrical connection boxes by a couple of inches. Didn’t know is this was for neatness or because of a danger from heat. LED lights generate little heat, and this was the application I had to consider.
    Thanks for any information you can provide.

    1. Electrical and heating appliances often require a minimum air gap separation from surrounding materials (e.g. 1″). Be sure to check the product design guides. Spray foam performs well in fire rating classifications, but is not considered a non-combustible material (e.g. concrete). Also, because of acceptable flame spread performance, spray foam insulation typically does not require an ignition barrier in crawl spaces and attics.

Leave a Reply

Your email address will not be published. Required fields are marked *