Spray foam for the eco-conscious - Fine Homebuilding

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The Deans of Green

The Deans of Green

Spray foam for the eco-conscious

comments (31) June 17th, 2009 in Blogs
RYagid Rob Yagid , senior editor

Hardworking crops. The oil from soybeans, which is also being considered to create alternative forms of energy, is replacing the petroleum in some spray foams.Click To Enlarge

Hardworking crops. The oil from soybeans, which is also being considered to create alternative forms of energy, is replacing the petroleum in some spray foams.

Photo: BioBased Insulation

I've gotten a lot of good feedback on an article I wrote for FHB#204 on spray foam. Many folks were concerned about the environmental impact of the foam itself and its toxicity to the resources we're ultimately trying to conserve. Below, I'll share a little bit about the make-up of the foam and also describe what makes some foam "green". For those of you interested in learning more about the various players in the spray-foam market right now, see the source list from my article toward the bottom of my post. And, of course, feel free to comment if you have opinions on the performance of spray-foam or its greater environmental impact.

Spray foam is made of a two-part mixture. The A part is isocyanate, a petroleum-based chemical made by only a handful of companies in the world. The B part contains a catalyst, polyol resin, a surfactant, and a blowing agent.

Consuming fossil fuels to make products intended to conserve fossil fuels makes little sense to a lot of people. All spray foams contain a certain level of petroleum in their A component and in their B component. Manufacturers such as BioBased Insulation, Demilec, and Icynene have created more environmentally benign spray-foam products by reducing the amount of petroleum used in their B component. They replace a portion of the polyol resin, which makes up 20% to 30% of the B component, with a renewable resource such as soybean or castor-bean oil. Apex even has a sucrose-based polyol. Manufacturers say that the transition to bean oil or sucrose doesn’t alter the look or the performance of open- or closed-cell foam in any way.

The amount of soybean, castor bean, or sucrose found in foam varies by manufacturer, so identifying the “greenest” foam might not be so easy. According to the U.S. Department of Agriculture, only 7% of a spray-foam product needs to be made of a renewable resource to be labeled as a bio-based foam. This, of course, doesn’t factor in the petroleum fueling the crop-cultivation process. I wonder how "green" these foams really are? Sure, they may be a bit more healthful than strictly petroleum based foams, but can manufacturers be doing more to produce a better spray foam product?

Although this is not a complete list of spray-foam manufacturers, it is representative of the larger national companies. For assistance in finding a spray-foam insulation contractor, visit the Spray Polyurethane Foam Alliance.

Apex Foam Industries     Fomo Products
                              Great Stuff
BioBased                        Icynene
CertainTeed                   NCFI
Chemical Design            Tiger Foam
Corbond                         Touch n' Seal
Demilec                          Urethane Soy Systems 
Foametix                        Versi-Foam Systems

Read the complete article...
Spray Foam: What Do You Really Know?
To get the full benefit of this superinsulation, you must understand the difference between open- and closed-cell foams, how they perform, and how they're installed
by Rob Yagid
Get   the PDF



posted in: Blogs, green building, insulation

Comments (31)

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Posted: 9:53 am on November 19th

ProblemSPF ProblemSPF writes: Continuing from last post...our SPF chamber tests showed levels of formeldahyde (which Demilec claims their SPF to be free off) along with 6 pages of other nasty chemicals. Many chemicals associated with flame retardants, which are bio accumlative and also leachs out as dust.
The chambers were set at a low temp during the testing which is not indicative of an underside of a roof deck. It would be probable to estimate higher levels of offgassing to occur during 9 months of the year when temp are higher than the low temp of the chambers.
Buyer Beware, is this another UFFI or asbestos???
The removal is not pretty, but has to be done since a demo of the house would cause the dust from the broken SPF to be an environmental hazard to the homes around us. Certainly not Green.
Posted: 1:41 am on January 4th

ProblemSPF ProblemSPF writes: Our family is removing our ENTIRE new home of its Demilec Sealection Open Cell spray foam in hopes of ridding the home of the chemical shown to be offgassing from it. We are in contact with 21 other families unable to live in their homes with the same product. Demilec is covering the cost of removal for a couple homes, but not ours or others who have already spent tens of thousands of dollars trying to remedy thier toxic homes.
People need to be informed of the greenwashing going on with SPF. It is not improving IAQ, it does not decrease asthma (isocyanates Are a SENSITIZER for asthma and can increase asthma via inhalation and skin contact). What is even scarier are the flame retardants used in side b( side b of ALL open cell SPF is composed of approx 70% trade secret ingredients - meaning no regulation). Our s

Posted: 1:27 am on January 4th

AKhiker AKhiker writes: A local commercial construction company specializing in foam has advised that the soy-foam will retain moisture and lead to mold and other problems. They put soy foam (open cell) and traditional closed-cell petro foam in a bucket of water. The soy foam absorbed a ton of water, but the other did not.

They also advised that the R value is lower, so you need a thicker layer of foam.

Has anyone heard of these issues?
Posted: 2:56 am on April 16th

mysteryman mysteryman writes: Seems like all of you are missing a main point. Either soy or corn based foam insulation is GMO. Would you want to breathe that in your house?
Posted: 12:41 am on March 30th

Dahveed Dahveed writes: Foam is an excellent insulation product. Its biggest downside is cost. If some of the petroleum used in the mix can be reduced by the use of plant based oils, then thats a good thing. My only complaint is that the consumer doesn't value the insulation in their home and only pays extra for nice countertops, not the actual mechanics of the home (at least in my neck of the woods). I guess that makes some sense - friends and family can see the nice countertops, but not the lower energy bills. Perhaps everyone should frame their energy bills by the front door to show off how well their house performs energy wise.

Regarding the whole food vs non-food use of the crops and/or the land that grows it I have this to say. If we have to use food crops to replace or reduce our energy usage we should. The US and its citizens are being CONSTANTLY attacked for using too much energy or creating too much pollution. When we actually try and do something about it with what we have available locally, we are attacked for taking food from starving people. The argument about food crops being used as energy taking away from staving people in Africa is a little like the "clean your plate" argument your parents might have used on you to get you to eat your veggies. People in Africa should be subsisting on locally grown food crops and we Americans need to reduce our dependence on oil and coal for energy and reduce our energy footprint.
Posted: 10:27 am on July 6th

RYagid RYagid writes: Bski, Bruce Harley recommends treating a crawl space like a small basement. A crawl space can be a huge source of moisture and mold in the home. Simply venting a crawl space doesn’t adequately remedy the situation. It’s best to insulate the crawlspace walls, seal up any outside air sources and install a class I vapor retarder over the floor (be sure all seams are taped). He also encourages water drainage to be integrated into the crawl space to manage any bulk water issues that may arise.
Posted: 2:42 pm on June 29th

RYagid RYagid writes: Zimmerdale, I'm not so sure how I feel about your solution. I suggest designing the house the way you want it, in a way that makes sense for future occupants. If someone does decide to opens those walls 30 years from now to remodel the home, I’m not sure they’ll know what to make of the chases you’ve installed. I can picture them just ripping them out and starting over, which just leads to a waste of resources, time and money on your part. If you do decide to go ahead with the plan be sure whatever plastic you choose to use as a chase can withstand the heat generated by the foam's exothermic reaction.
Posted: 2:31 pm on June 29th

zimmerdale zimmerdale writes: I am remodeling our small old house with Passivhaus standards in mind. I plan to use closed cell spray foam to maximum the R-value in our 2x4 walls (plus sheet foam on the exterior). I too am concerned about "gluing" wires and pipes into the cavities. I'm toying with ideas of using a kind of conduit that can be standardized in the walls for future changes. Plastic pipe run horizontally at approximately 16" and 48" high would allow for standard outlet/switch levels. Plastic pipe could be cut into to access the channel. This would probably work best in conjunction with 2x2 horizontal firring strips on the interior of the 2x4 walls. I'm also looking at the readily available flex conduit in a large enough size to allow future wire fishing.

Any thoughts or suggestions?
Posted: 10:27 am on June 29th

Rozz Rozz writes: Bosn, you have a good point about problems with remodeling. One solution to this is too apply the foam only one to two inches thick against the exterior sheathing and fill the space between that and the finished wall with Batts. This provides EXCELLENT R value and still allows for remodeling. I did this in a home I recently built and it is amazing how well it holds heat and deadens sound. I would even argue that despite the reliance on fossil fuels for producing it there is less use in energy for heating/cooling in the short and long term.

Epernik was worried about the house being too tight. There is a simple solution to this. Use an Air/Heat Exchanger that is set to run either on a pressure basis, moisture basis, manual demand or percent time. This is a system that can connect the exhausts in the kitchen, baths and laundry rooms. It exchanges moist stale air for fresh air as well as transferring some of the out going heat to the incoming air. If you are using a wood burning stove, insert a dampered vent to the outside for additional incoming air.

I have used the do it yourself foam and the stuff is GREAT. I would never build another house without it!

Posted: 10:46 pm on June 28th

bski bski writes: I was wondering about the illustration showing insulating the inside of the crawlspace walls. I was taught that you should always vent a dirt crawl space, in which case insulating the inside of the walls is useless.
Posted: 10:34 pm on June 28th

bosn bosn writes: The only problem I have with spray foam is that it seals up a wall cavity so well that when you try to do work in the wall at a later date it is very difficult and costly. I am an electrician. I do alot of remodel and service work. Adding outlets and cables for whatever new technology is the thing is a commonplace request from customers.

Being able to fish a cable through a wall makes such a job easier and less costly. If a wall is insulated with anything that you can push a fishtape through and subsequently pull the cable through, you have few problems.

Unfortunately, foam fills the cavity and you can't push a tape through it. The solutions to this would be to use a flex bit to drill the foam, (but I have never heard of anyone having success with that), or removing wall board running the cable in a channel made in the foam and then patching the wall and wall finish. (Not a good option when the customer has an expensive wall treatment that is no longer available.

You can't plan for every contingencey when building a house, but when such a problem is commonplace (well, to electricians anyway), a method might be developed to allow for this in the future. Say, leaving an air space of one inch between the wallboard and the foam. Would that work? I don't know. Heck, I don't even know how you would do that quickly and easily, It's just something to consider.
Posted: 10:32 am on June 26th

RUSSR RUSSR writes: One aspect that I have never been able to get an answer on is- What about insect resistance. I have seen spray foam loaded with carpenter ants. You could watch the debris falling from the holes and clearly hear the chewing! The foam protected the ants well from the several bug sprays that were tried. I have talked to reps who did not know how to prevent the problem. What do you do?
Posted: 11:52 am on June 25th

RYagid RYagid writes: Mysticooks, I’ve never heard of spray foam shrinking over time. Open and closed cell foams certainly have different expansion rates, but not shrinkage rates. I’d question the installer who provided that information.
Posted: 11:14 am on June 25th

Ed_Pirnik Ed_Pirnik writes: Seems as though with the elimination of backing paper used on conventional fiberglass insulation, homeowners put yet another nail in the coffin of potential mold. Less cellulose material (food) for mold spores means a safer living environment. That plus the technology's effectiveness as an insulator equals a potential win, win situation.

I love this stuff however there is one thing that worries me. Aren't we effectively hermetically sealing (OK, perhaps that's a bit dramatic) our houses by using spray foam technology, and thus having to deal with stale air and the buildup of stray residual chemicals? Seem as though the tighter we seal up our homes, the more potential there is for certain problems to arise.

Just playing "devil's advocate here.



Posted: 9:18 pm on June 24th

RYagid RYagid writes: LuckyPenny,

You bring up a really good point. Personally, my trust and faith in industrial agricultural run’s about as deep as it does for big oil. In my opinion, GM crops and monocultures for the sake of production and profit at the expense of the ecosystem (both local and global) is no better than the extraction and mass consumption/burning of petroleum. My fear is that these “green” foams are going to be fed to the market as a true alternative to petro based foams. They seem to be more environmentally benign, but I’m not convinced. I wonder if these companies are just moving the chess pieces around, allocating energy consumption in different ways that ultimately do little for ecological progress, but a lot for corporate branding. Is the focus on selling a new product to a “green” crazed consumer market, or is the focus on making a better product for the sake of doing it right, despite the potential loss in revenue or output? I’d love to see some numbers that show the real difference (including embodied energy) between these bio-based foams and standard foams. I’d like to see a consumer market that is a lot less complacent, and one that’s willing to keep pressure on manufacturers to develop better products. I’d also like to see what companies are doing to make improvements on the manufacturing of their foam.

Posted: 11:07 am on June 24th

mysticcooks mysticcooks writes: When we built our house 2 years ago on Tybee Island, GA, we were told that closed cell spray foam insulation shrinks more over time than open cell foam. What is the real shrinkage for both types of foam? We're about to insulate an addition on our niece's house in Westerly, RI and want to pick the best one!
Posted: 11:45 pm on June 23rd

Lavenderfoam Lavenderfoam writes: In response to NKHAN's post about HCFC's everyone should know that in the United States the use of HFC blowing agents was banned by the Montreal protocol. All closed cell spray foams use a zero ozone depleting blowing agent 245fa by Honeywell. This blowing agents has no adverse effects on the ozone, unlike the water blown spray foams that use CO2 as the blowing agent. I would also like it to be known that the use of PBDE fire retardents is not used by any of the major manufacture's of spray foam today.

When a life cycle analyst was completed on polyurethan spray foam it was determine that the embodied energy of SPF was higher than traditional air permeable insulation (fiberglass, cellulose, recycled blue jeans just to name a few low quality insulations), but it the amount of energy it saved every year, buy approximately the 3rd year in use, the SPF had half as much total energy useage (embodied energy + energy needed to heat and cool a building) compared to traditional air permeable insulations.

The choice is simple, use a small abount of pertoleum based insulation now and safe enormous amounts of fossil fules later, or use a low quality insulation such as fiberglass today and burn unneeded amounts of natural gas or coal tomorrow and in 15 years people will have to rebuild the structure because of all the mold that is allowed to grow in the wet, ineffectively insulated walls.

Oh ya, I almost forget, can anyone name which car recieved the award for the smallest carbon foot print?
Posted: 1:40 pm on June 23rd

nkhan nkhan writes: It takes 40 years of energy savings from the insulation (CO2 saved at the powerplant) to "pay back" the injection of HFC into the atmosphere that occurs when blowing foam using the typical spray foams. For this alone, if you have to use foam, at least go with the foams that have the reduced content of petroleum-based polyols, and that are water-blown, free of HFCs and PBDEs, until even better products come into the market. Like the Icynene - http://www.sprayfoam.com/npps/story.cfm?nppage=230. Air krete sounds interesting...

Posted: 11:40 am on June 23rd

luckypenny luckypenny writes: Because we don't eat building products made from agricultural products we don't tend to think about where they come from. The majority of soya beans grown in the U.S. are genetically modified crops that use a lot of pesticide. North America is way behind Europe in understanding how the devestating effect GM plants are having on natural ecosystems.

Most of the strongest voices warning the public and governments about human health hazards and the dangers to ecosystems are big names in the science community. Here are two big names: Steve Jones, Professor of Genetics at University College London, U.K.. author of Darwin's Ghost, a very readable updated version of The Origin of Species that has a good explaination of how GMO significantly messes up ecosystems which are by definition interconnected systems. Arpad Pusztai, also a British scientist. http://www.acresusa.com/toolbox/reprints/Feb04_Smith%20Interview.pdf)

For independant scientists and farmers vs business and politics of GMOs read Seeds of Deception by American Jeffery Smith: http://www.seedsofdeception.com/Public/Home/index.cfs

There is also a documentary film "The World According to Monsanto".
Posted: 12:34 am on June 23rd

ChristophW ChristophW writes: As the author stated, to some people it does not make sense to use a fossil-fuel consuming product to replace fossil fuel consumption. IN my opinion, you have to look at the savings and if there are significant savings in total fossil fuel consumption (also compared to other insulation technologies like blown cellulose), this alone will justify a technology like foam insulation.

In our 1905 three story home in New Hampshire last winter we had 4" closed cell foam sprayed under all the roof area, which spans the third story plus another attic floor. Additionally, we had some of the accessible wall surfaces sprayed (e.g. where we just did demolition). Shortly after Before the house was absolutely drafty and you could feel the wind blow through. Afterwards, the upper floors (incl. attic with all doors closed) stayed cozy warm.

We cannot truly measure the impact of our improvements because we also got the windows replaced and other work done in Janruay and February, and for days at a time we had "things" open and the heat running. However, just from a living comfort point of view, the foam insulation makes a huge difference. Just as in winter time the upper floors stay warm (even though heat rises not necessarily a given due to only two heating elements, a closed door between 2nd and 3rd floor and the large roof area), the upper floors did not significantly heat up during those few hot days in NH 2009 (I know because that's where my office is.

Next winter we'll be able to report on the total savings of our improvements.

@bfield: No experience with that but from what I know the cost is in the material. Labor is minimal compared to that. The combined price from all that I saw is usually around 1$ per inch per sqf (will vary slightly on the foam type and manufacturer). I found a DIY kit online (don't remember the link) that comes in two "propane" tanks. The price down the sqf and inch thickness was basically the same as the professional installation. One problem is that the tanks and the gun cannot be recycled -> waste and cost overhead. So unless you need to just insulate small areas, it's probably not worth it doing it yourself.
Posted: 11:22 am on June 22nd

DaveAdams DaveAdams writes: I am about to have a contractor spray polyurethane foam into my house and he has given me a choice between PolarFoam 7300 regular and PolarFoam 7300 soya. I am having difficulty deciding. My contractor prefers the regular stuff because it is easier to work with and has better coverage and therefore will price the job a little cheaper. On the other hand the soya based product has a GreenGuard certification.

As I understand it the difference between the two is in the blowing agent. The SOYA is zero ODS (ozone depleting substance) and has no HFC (hydro flouro carbons???). As far as health to the homeowner there is absolutely no difference. They both contain recycled products. The PF-7300 has a slightly higher Rvalue of 6.9 v 6.0 for the SOYA. Soya more environmentally friendly. All foam starting in 2010 will be SOYA or the type of blowing agent used by the soya due to government ruling.

Any comment to help me decide? Thanks in advance.

Posted: 10:15 am on June 22nd

colerdotcom colerdotcom writes: I use the soy based spray foam every working day. It is a great product which has a higher soy content than some of the competitive soy or bio content spray foams. As stated, the Polyol makes up 20-30% of the of the total spray foam raw materials and BioBased polyols are 97% pure. You do the math and I have yet to see a bio content material match or exceed this. This blows the government requirements of 7% minimum out of the water.

As far as competing with food sources, yes, Soy beans do, but soy has also been the number one exported agricultural product from the US for many years. Soy crops are also good because you can commonly get two crops within one growing season year. The soy availability has been hurt by the latest trend of farmers to grow corn because of the prooted demand for use to create ethanol. So, with a high availability of soy beans, the oil can be used for many purposes, and the soy pulp can be used for food or other as needed.

Flash-n-Batt: Some installers are using a 1/8"-1" thick layer of foam to seal the building and then putting fiberglass in the cavities. Our company does not supprot this practice and will refuse a project that has this specified. It goes against good building science principles where the foam does not block enough heta transfer to prevent condensation within the walls. We have heard from some prospective customers who chose to go this route and found water in their walls behind the fiberglass. The more cost effective route is using open cell foam at 3" or more in walls.

JFink, the product available at HomeDepot is SoySeal and it sounds like it was either cold or not shaken when you used it. There are materials inside that need to be properly mixed and at the proper temperature to make "good foam". We use the SoySeal products and they work great. We've found them to have a better end product than the great stuff products by Dow.

Airkrete is different from spray foams as it is more brittle once it sets up and the expansion and contraction of wood with moisture and temperature variations can cause it to crack or crumble within the cavities. It also commonly oozes into the electrical lboxes and can fill them if not carefull during the install.Spray foams are more flexible and more durable in the long run.

So, Yes, foam uses some petroleum to create the insulation materials in our buildings, but when you look at the overall life savings of petroleum it nets, the amount of oil used is minimal. A 2400 sqft house insulated with BioBased Insulations will use less than 175 gallons of petroleum based products. This is over 85 gallons less than a 100% petrolem based spray foam. Many houses we've worked in use more than this in one month of heating their home. In many of these same homes, we're seeing a 30-50% decrease in energy consumption. So, this is a savings of fuel oil at about 50 gallons per month and this continnues for the life of the building.

So, if you're still not in agreement, then look at the alternatives and the energy usage consumed to melt sand into glass and then melt glass and use massive amounts of electricity to compress air which is used ot blow the molten glass into fibers. There are HUGE amounts of energy used in the creation of fiberglass and it doesn't save what they claim it does as air passes right through it. It's the same material used in most furnace filters - only thicker so how can we expect it to perform differently?

DIY kits of spray foam are typically only a closed cell foam of a 1.7-2.0 lb/cuft density. These are typically much more expensive than even an installed price of a professional contractor using larger professional equipment. It's not easy to install properly and it's best left to someone who does it as their profession to make sure you are getting your best return on the investment. I've used the DIY kits and even sell them. They are very useful in small areas of repair or small applications, but larger areas are typically more cost effective with a professional's services (which includes install time and labor, and safety equipment).

Spray foam is the insulation product of the future and I believe it will completely replace the use of fiberglass insulation, once people understand how it works and they see/feel the benefits!

Posted: 9:23 am on June 22nd

sjdehner sjdehner writes: Our house is insulated with Icynene and we can report that it is a VERY effective insulation! Here in Maine we used less than 300 gallons of propane (along with a little wood) last year to heat our two story house from basement to attic. While not perfect Icynene insulation is certainly a reasonable end use for petroleum.

Another insulation we are considering for our next house is a product called Air Krete, made from magnesium oxide, and I quote from their website (www.airkrete.com):

1. air krete® Insulation sample was resistant to mold growth at both 75% and 95% relative humidity. Neither molds were found to amplify in the materials at either humidity.

2. air krete®, over time, maintains a very high insulation value. (R = 3.9 at 2.07 lbs/ft3)

3. air krete® seals very effectively around the edges from infiltrating air.

4. air krete® does not expand, shrink or settle and is 100% cavity filling. It fills around and behind any obstructions and crevices. ( Dimensional stability- ASTM C 951: zero shrinkage)

5. air krete® does not inflict damage to environment or man. Material is non-toxic, does not create any ozone-depleting CFC’s and does not contain any formaldehyde or carcinogenic fibers.

6. air krete® does not burn and does not release any smoke and is also used as fire-stop material. ( ASTM E 84: 0- flame spread, 0- fuel contribution, 0- smoke-Test extended to 30 minutes with no further flame progression)

7. air krete® has a de-oiling effect and deters any rodents or insects.

8. air krete® is fully recyclable and can be used to enrich soil.

9. air krete® is very flexible and adaptable in its use in wall, roof and ceiling cavities in new or old construction.

10. air krete® is very cost-effective.

11. air krete® has the ability to absorb moisture without loss of insulation value. It therefore tempers and regulates indoor air humidity and enhances healthy and comfortable air quality.

12. air krete® is also a soundproofing material and used very effectively in interior sound partitions. In encasing plumbing pipes, water noises are very effectively reduced.

13. Because air krete® is Magnesium Oxide (MGO), a refractory cement it is ideal for high temperature applications.

While I have not used Air Krete it seems to be a "greener" product than any of the other spray-foams mentioned with several added benefits such as being non-flammable and 100% recyclable, et al. This product is impressive.

Great article by the way.

Posted: 8:06 am on June 22nd

iMarc iMarc writes: I was hoping the FHB#204 article on spray foam might include some discussion of Peter Pfeiffer's detail that shows a 1" flash coat of closed cell foam sprayed onto the backside of the exterior sheathing with the remaining depth of the stud space insulated using damp-blown cellulose.

I have my doubts about considering any type of spray foam to be a truly green or environmentally friendly product, yet it does have some specific advantages that other loose-fill or blown-in products don't have. I think there's some validity to the idea of using minimal quantities of spray foam specifically for air sealing and for insulating at rim joist and difficult to access areas, but I would prefer to use cellulose for the bulk of the insulation. Cellulose uses less energy in production than any other insulation material, it contains no petrochemicals, it's recycled content is 100%, it's blowing agent is simply air and it further minimizes greenhouse gas emissions by diverting newspaper from landfills.

Another issue that is rarely considered when building a new home is that the insulation won't be used forever. What is done with any particular material at the end of its useful life span is a factor that must also be considered when evaluating how green a material may be. When a foam-insulated building is demolished, will it be practical to remove the lumber, wiring and plumbing pipes from the adhered foam so that they can be reused or recycled or will it be so difficult to separate materials that the whole thing will go into a landfill?

I would be very interested to hear more from Peter Pfeiffer about his theories behind the detail shown in the article.
Posted: 6:14 am on June 22nd

builderwill builderwill writes: To bfield:

I have used the DIY kit from RHH Foam Systems. I have superintended a number of jobs that used coated foam roofing applied using a truck mounted distributing system. Compared to those, the DIY kit I purchased costs more per CF. I purchased aprx 10 CF for about $350 for a roof repair. The system came with easy to understand directions and was simple to operate. It did not produce a foam surface that was as uniform and consistent as a truck mounted rig but that matters more for roofing than for wall insulation. The performance of what I installed seems to be identical with what I would expect for a truck mounted distributing system. As with most trades the actual results will vary with the skill of the applicator.
Posted: 8:18 pm on June 19th

RYagid RYagid writes: Foamwiz,

Do you know more about the cultivation of the castor bean? I'm hoping someone can weigh in on the real difference from a strong agricultural perspective. When I first researched castor oil being used in spray foam, I was alarmed to find that the deadly poison, Ricin, comes from the castor bean. I later found out that the toxic chemical is only found in the bean's shell. Manufacturers are careful to extract the oil from the bean without contaminating it with Ricin. It seems like a dicey operation, and my hope is that any manufacturer using castor isn't skimping on quality control measures or disposal practices.

Posted: 12:50 pm on June 19th

Lavenderfoam Lavenderfoam writes: What about recycled polyols? Also I have heard the bio-based polyols require more petroleum to get the same amount finished product. This requires more barrels and more freight to transport the materials resulting in an increase in the total amount of petro used.
Posted: 10:58 am on June 19th

JFink JFink writes: The only "green" foam I've tried is the disposable can version from Home Depot - I don't recall the name, but the foam was soy-based. I was disappointed with it's performance, though. When the foam hardened it was very brittle to the touch, almost to the point of collapsing or shattering if disturbed. The poly and latex based foams have a much more resilient performance, by comparison. I wonder if the foams for full insulation perform the same?
Posted: 10:05 am on June 19th

foamwiz foamwiz writes: There is a better idea. Foam using castor bean oil instead of petro based or soy oil based is available. Castor plants do not compete with food crops (as does soy beans) for land and water.
Posted: 9:42 am on June 19th

bfield bfield writes: Anyone out there have any experience with the "do it yourself" spray foams?
Posted: 9:39 am on June 19th

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