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Armoroc Cement-Bonded Particle Board

Armoroc structural cement-bonded particleboard is made with portland cement and 28% pre-consumer wood fiber… Read more
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  • These products are environmentally attractive because they need to be replaced less frequently or their maintenance has very low impact, both of which can reduce costs as well as environmental impact.
    Robust answers on typical service life of products can be hard to come by, however. In GreenSpec we reserve this criterion for products where the material is clearly more durable than alternatives, such as an exceptionally traffic-resistant polyurethane floor finish. We refer to standardized tests for durability when they are available and appropriate.
    We also consider “appropriate durability”: long life is more important in a building envelope than in interior finish materials that will be replaced for aesthetic reasons. Here, reduced maintenance can be particularly important. An example is resilient flooring that doesn’t require regular waxing: an unnecessary use of resources and a health hazard.

  • Just how low the VOC level needs to be for a given product to qualify for inclusion in GreenSpec depends on the product category. For most products, we require certification to California’s health-based emissions standard, CDPH Std Method v1.1 standard (also referred to as California Section 01350), which tests a product’s resultant VOC concentrations in the space after a given period of time. For wet-applied products like paints, caulks, and adhesives, we still also look for VOC content instead of, or in addition to, verified low emissions; this is because emissions testing doesn’t adequately test initial offgassing, and VOC content is currently the only widely available proxy.

  • Periodic pesticide treatment around buildings can be a significant health and environmental hazard. Green alternatives obviate the need for pesticide treatments. Examples include physical termite barriers and bait systems that apply toxins in a much more targeted way than broad-based pesticide application.

  • While resilience—the ability to weather natural disasters and maintain livable conditions in the aftermath of disruptive events—is mostly an issue of building design and community preparedness, certain products can help. For example, almost all heating systems require electricity to operate even if their primary fuel is oil, gas, or wood pellets; systems that allow operation even if grid electricity is not available are more resilient in the event of power outages. Rainwater harvesting, water storage, composting toilets, and waterless urinals contribute to resilience not only in drought-prone areas but also during power outages in any home dependent on well water. Solar water heating systems that can operate without utility power, and back-up power systems that are more energy-efficient than standard generators, may have this attribute.

Armoroc structural cement-bonded particleboard is made with portland cement and 28% pre-consumer wood fiber. These panels can be machined and worked with typical carpentry tools; fasteners should be resistant to corrosion. This formaldehyde- and VOC-free particleboard is factory-sealed on all six sides and available in 4'x8' or 4'x10' sheets and in thicknesses from 5/16" to 1-1/2". Tongue-and-groove edges are available on two or four sides. The manufacturer claims that its higher percentage of wood fiber produces a stronger panel. Due to the energy intensity of the cement content, this product should not be considered a green substitute for particleboard except where significant resistance to fire, moisture, termites, or vermin is required.

Cement-based panels can offer durability and indoor-air-quality benefits when used where moisture, mold, or insects are a problem, or where fire-rated panels are specified, and GreenSpec lists them due to these benefits. However, their product is energy intensive, relative to conventional sheathing or wallboard.

Cementitious sheathing products are made from portland or magnesia (magnesium oxide; MgO) cements, fillers, and reinforcement. Both portland and MgO cements release carbon dioxide as result of calcination, but MgO is fired at a lower temperature (approximately 1290°F vs 2700°F, respectively) and for less time, resulting in approximately 20%-40% less manufacturing energy. Unfortunately, MgO panels are currently made in China and are not widely distributed in the U.S., so they can be expensive, whereas portland cement panels are often made regionally across the U.S.

LEED Credits

EQc4.4: Low-Emitting Materials—Composite Wood&Agrifiber Products

IEQc4.4: Low-Emitting Materials—Composite Wood and Agrifiber Products

Ratings and Commentary

Low-emitting - a life cycle perspective on Armoroc?

Is a cement-bonded board "low-emitting" and worthy of a LEED point for IEQ?

As EPA delays responding to the Supreme Court decision that requires it to address carbon dioxide emissions as a pollutant under the Clean Air Act, others, such as California, are taking action to reduce the CO2 emissions from the cement manufacturing process. Cement is one of the most greenhouse gas (GHG) intensive building materials used today. Substituting it for other binders in sheet materials like particleboard or fiberboard is hardly worthy of credit under LEED.

Well, you say, we are talking about indoor emissions here, not emissions in the manufacture of the product. I say, if you have to do something really bad elsewhere in the life cycle in order to get your LEED credit for a low-emitting product, then your are 'robbing Peter to pay Paul.'

Furthermore, we are at a point when any unnecessary or avoidable GHG emissions should be avoided if other alternatives are available. Buildings are the single most GHG intensive sector of the economy according to a new study published in the scholarly journal, Energy Policy, "Potentials and costs of carbon dioxide mitigation in the world’s buildings." It is authored by contributors to the IPCC's Nobel Prize-winning Fourth Assessment Report released last year, Diana Urge-Vorsatz and Aleksandra Novikova of the Department of Environmental Sciences and Policy, Central European University, Budapest, Hungary, and available in Energy Policy Volume 36 pages 642–661. Their paper was based on the assessment of 80 country- or regional-level mitigation studies throughout the world.

Let's not miss every oppotunity we have to cut GHG emissions as the net life cycle impact of the material and other design and construction choices we make.

Additional benefits to Armoroc


Your expertise in this area is acknowledged and appreciated. However, let’s not lose sight that Armoroc Structural Cement Board is taking a step in the right direction over traditional methods of fire-resistant construction.

In metropolitan areas where wood is not allowed in floor construction (New York City, Chicago, Etc.) there are limited cost-effective alternatives to pouring concrete on metal deck, especially in multi-story residential construction where this product is being used extensively.

Armoroc offers both economic and environmentally-friendly advantages over pouring concrete such as:

* 3/4" Armoroc weighs only 5 lbs/sf vs. 25 lbs (+/-). This reduces the overall weight of the building allowing reductions in structural support framing and/or foundation materials.

* 3/4" Armoroc is a thinner floor system than poured concrete. This may allow an overal reduction in building height, which directly translates into less building materials.

* Since Armoroc installs like plywood (by carpenters), you eliminate the entire wet-trade including concrete trucks, pumps (and the requirement to close down streets). This also eliminates metal decking, related accessories, as well as curing time and temporary heating requirements. Once Armoroc is delivered to site and installed, it's ready to finish.

Armoroc may utilize Portland Cement in it’s composition, but there are advantages to using this board over many other traditional systems. This is only one example – there are advantages to using Armoroc vs. FRT Plywood, built-up roofing systems, etc, etc.

Thanks for your feedback and consistent efforts to educate and increase awareness for sustainable construction. If there are additional questions please contact me directly at mike [at] ameriformllc.com

Best Regards,

Mike Kavanagh Ameriform LLC

Amoroc is very good, but is it good enough?

Hi Mike,

Thanks for your kind and generous remarks. Actually, the more I learn the more I know that my expertise is really limited -- mostly to knowing something about how little I really know compared to what needs to be known.

The additional benefits you listed are all valuable characteristics of your product. I concur that these are all important performance characteristics. They illustrate that uni-dimensional criteria for "Green" materials are dangerous at best.

This discussion and our respective comments illustrate the complexity of determining what is "green" or "sustainable." I presented a talk at the recent ASHRAE meeting with the title "what is a green material?" It can be downloaded from my web site -- http://buildingecology.com. Note that I am in the process of revising slide 11 which had some contradictory info in it. The goal was simply to show that as buildings last longer, embodied impacts count less relative to use phase impacts; but as buildings approach net zero operational energy, embodied energy becomes a larger fraction of total attributable energy impacts.

The theme is summarized well by H. L. Mencken: "For every complex problem there is an answer that is clear, simple, and wrong."

I was curious to know more details of your product's performance. So, I looked at the web site. It said: "Acoustic Performance: Has a density of 77lbs/ft3" (the MSDS says 78 lbs/ft3) -- if these are actual dimensions rather than nominal, this would translate to 4.8 lbs/sq ft for a 3/4" sheet, even better than you stated in your post.

It also said it won't support mold growth. I would be willing to bet that I could grow mold on it in a sufficiently moist environment, especially if surfaces were exposed to air with even normal air concentrations of typical particulate matter. Sure, if there are no nutrients, mold can't grow. But unless all surfaces are clean and protected from soiling or particle deposition, it will acquire a coating that can support mold. That's why mold can grow on window glass!

What I don't see on the web site and want to know is what gives it its tensile strength? I can only hypothesize the presence of fibers of some sort, but even so, an all-cement panel would need a real dense mesh to not break under a large, dynamic point load. I worked with undulating asbestos-cement panels (Eternit) when I was an Volunteer Architect in the Peace Corps during the 60s. The corrugations gave it structural depth and the fibers gave it tensile strength. What gives Amoroc its strength?

I look forward to learning more about the product. I also want to reiterate the importance -- even the urgency -- of reducing GHG emissions. While the board may last a long time in a very long-lived building, the production of Portland cement is still very GHG intensive. IMHO, we are in a crisis situation with respect to reducing the build-up of climate-forcing gases in the Earth's atmosphere.



OOPS! Wood fiber!


I'm sorry, I missed the wood fiber part that I saw after clicking "submit comment."

So, it is not VOC- or formaldehyde-free after all. Not a big deal if the fibers are thoroughly embedded in a very dense cement matrix, but a picky point that should not be ignored in promotional materials. All wood contains and emits formaldehyde; wood is essentially VOC molecules arranged in useful ways. Remember, wood is organic - it is made from organic chemicals. If a lot of them weren't volatile, wood wouldn't have any odor. As a gross rule, the more the odor, the more VOCs being emitted. Some of these will react with oxidants in the air and form even more formaldehyde, acetaldehyde, and higher molecular weight aldehydes.

There is no free lunch.


Keep Up The Good Work!


Much of the tensile strength comes from the mineralized, post-industrial wood fibers. We have called on the services of a product specialist to investigate your post and suggest any modifications as-needed. Thanks for your interest in Ameriform and our family of fire-rated building systems. We would like to extend an open invitation to continue any discussions regarding fire-resistant building systems & sustainable building practices on the Ameriform Message Board available here: http://pub33.bravenet.com/forum/2757503319/

Keep up the good work and good luck with your efforts to promote sustainable building practices.

Best Regards,


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