Off-site construction – SIPS
I have had a strong interest in off-site construction. Through the last 11 months I have been comparing site-built vs. off-site construction using volumetric modular and determined due to the delivery costs it made sense to shift to on-site construction which I will very likely execute in the same time frame.
Recently, I had watched a video that Matt Risinger posted regarding SIPS construction using Extreme Panel and it peaked my interest.
After looking into the costs again with SIPS the overall costs seemed to be a factor and since the house design didn’t allow the roof panels to work I again tabled the idea for this particular house.
Then in researching further I found a company that is local to my area called Eco Panels. This could align well and now I am thinking while not on this particular project maybe I am able to consider this in the future. I was able to meet the founder and he gave me a factory tour.
My question: From a green building point of view coupled with energy efficiency the difference between EPS and Spray foam…but, what Eco-Panels says is a proprietary blend of closed cell polyurethane foam created in part from a poly-alcohol derived from post process sugar-beets, what questions should I be asking or considering?
Is this marketing or is this a better version of foam?
This is from their website:
https://www.eco-panels.com/
Flame Retardant and Organic-Based Foam Core
We’ve never seen anyone else take a less than one-inch thick piece of insulation on their upturned palm and hold a 3,600° F torch on it for long periods of time like we can (please do not try this with your own insulation!). Our custom blend of closed cell polyurethane foam core is without peer for its structural and adhesive strength, thermal insulating ability and it is free of any formaldehyde, styrenes or VOCs, and rated with an ozone depleting potential (ODP) of zero and a global warming potential (GWP) of less than one. While most SIPs on the market use a urethane adhesive to bond the foam core to the siding materials, our injected foam itself is the only adhesive that bonds together all components of our building panels with a force of almost 50 lbs per square inch. That’s around 14,000 pounds of bonding force for every panel square foot! By comparison a typical stud frame wall system has only one hundred to two hundred pounds of bonding force per square foot with nails and sheathing. With our panels having a bonding force this strong, significantly fewer fasteners are needed to build a very strong home or structure.
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Replies
"Bio-derived" foam resin is almost entirely greenwashing. Typically a small percentage of the raw material is grown rather than extracted from petroleum, but not enough to make a significant difference.
My former employer used to take a handful of cellulose insulation, place a penny on top and melt the penny with a torch. It is impressive that they can do the same with foam; it just means that they are using a high percentage of flame retardant, and probably not the bio-friendly mineral borate that is used in good-quality cellulose and wood fiber.
"Zero ozone-depletion potential" is something foam manufacturers love to tout. It means they are following a law put into place over ten years ago.
By convention and not by fact or common sense, for some reason foam manufacturers don't include the carbon impact of anything except the blowing agent when reporting on global warming potential.
They are using hydrofluoroolefin (HFO) as a blowing agent, now industry standard for several years, which does have a low global warming potential when measured with conventional means, which among other things spreads the impact out over 100 years. We don't have 100 years to recover the damage done, and recent studies show that HFO may combine with other compounds to dwarf the impact of legacy, HFC blowing agents.
There are many advantages of using off-site construction. Using foam as the basis for offsite construction is a waste. There are many alternatives that use little to no foam or other climate-damaging materials.
Thank you for the response. In a world with so much information and varying opinions forums like this are helpful.
You're welcome, and I agree! To be clear, I think foam is an amazing material; it can do things that other types of insulation simply can't do. I just consider it the precious resource that it is and use it only where needed, rather than indiscriminately just because it's easy.
In the Huntsman (Canada) closed cell foam HFO blowing agent foam - it states that it "contains 22% renewable soybean oil and recycled plastic".
https://huntsmanbuildingsolutions.com/en-CA/products/closed-cell-insulation/heatlok-soya-hfo
I don't know about eco-panel, but whether or not 22% is small or makes a significant difference I'm not sure, but it is in my opinion - encouraging ...
I agree that using 22% recycled or bio-based materials is probably a good thing. But the fact that Huntsman's EPD combines Heatlok and Heatlok Soya into a single analysis shows that the soy element doesn't change the GWP by much, if at all, or else they would have separated the them.
It's also a good example of a true GWP. While they claim a GWP of less than one, if you add up the GWP100, IPCC AR5, you get about 2.5 kg/CO2e for every 10.85 board feet (12"x12"x1").
It also assumes that only 24% of the blowing agent is off-gassed over a 75-year lifespan, and that the foam remains in place without change for that 75 years. Both may vary significantly.
https://huntsmanbuildingsolutions.com/en-CA/sites/en_ca/files/2021-07/Final%20-%20Hunstman%20-%20EPD%20-%20Heatlok%20HFO%20and%20Heatlok%20Soya%20HFO%20-%20ENG.pdf