WOOD-FIBER INSULATED CONCRETE FORMS 

Poster Image Citations:

https://commons.wikimedia.org/wiki/File:Limestone_quarry.jpg

https://en.wikipedia.org/wiki/Lake_freighter#/media/File:AMAnderson.jpg

https://en.wikipedia.org/wiki/Cement_kiln#/media/File:LDCement2StringPH.jpg

https://agricfarming.com/how-to-start-waste-wood-recycling-business/

Materials:

Afrah Said

Isadora Goldschneider, Gabriel Bruce

DES 40A

Professor Cogdell

Materials for Wood-fiber Insulated Concrete Forms

Wood-fiber ICF sometimes referred to as woodcrete ICF (insulated concrete form) is primarily made from a combination of wood and cement. It's a new renewable material used for building structures. According to Durisol, a woodcrete company based in the UK,  woodcrete ICFs were created in Belgium in 1937. It is a low-carbon alternative for building material and possesses many benefits for the constructed structure. The production of wood-fiber ICFs consists of three main materials: mineralized wood, cement, and in some cases polythene (polyethylene). Each of these is made up of a number of raw materials combined together. Through research, I will be exploring the raw materials in each of these three main materials, that go into the manufacture of a woodcrete block, and into its distribution, transportation, use/reuse/maintenance, recycling, and waste management.

Wood-fiber ICFs may seem like they contain only a few materials, but I will be explaining the raw materials that go into each step as well as what purpose it may add to the product. First, we have the wood, depending on the company, the wood could be made of multiple things, but through further research, most are made up of recycled wood and/or wood fibers which are then mineralized. Through researching the mineralization of wood, the materials of which are unclear, but possible materials may include calcium carbonate, which could stem from where the wood is sourced and geographically located. But I’m also led to believe that the mineralization processing of wood also varies depending on where it’s made. Durisol, for example, uses a chemical solution to neutralize the sugars and proteins within the woodchip, this is their mineralization process that fossilizes the woodchips. Although the materials for mineralizing the wood are unclear, the result of doing so takes out all organic matter and practically makes it inert, making the wood properties fire-resistant and unappealing to insects. “The results show that the struvite mineralization treatment is a bulk modification technique that improves the fire resistance of wood. The mineralization can significantly influence the thermal decomposition behavior of wood, which results in an enhanced char formation. This char layer is a fire barrier that slows down the heat and oxygen penetration.”(Huizhang). 

Next, we have cement, the second key ingredient when constructing a wood-fiber ICF. Like the wood, the materials of the cement vary depending on the company and manufacturer, some companies use recycled cement while others use standard Portland cement. Portland cement is primarily made up of lime, clay, and flux agents, with lime stemming from limestones found on and beneath earth surfaces, and clay, being made up of silica, alumina and/or magnesia, and water. Silica is in quartz, while magnesia is produced from magnesite, both can be found on the earth’s crust. The integration of cement in the ICFs works as a bonding agent, it can ensure stability and withstand environmental factors, while the cement poured into the ICF works as an insulate. 

Lastly, we have polythene, not all wood-fiber ICFs contain this material but it is included in some. Polythene is made up of Ethylene which contains Petroleum. When petroleum, a substance found beneath the earth’s surface, when it is heated to 800–900°C, it can create ethylene. The combination of ethylene C2H4 chains then creates polythene. In the Durisol production process, polythene serves as a setting agent. It prevents evaporation and creates a chemical reaction that produces heat.  The heat emitted from the chemical reaction is used to not only cure the ICFs but also regulate the temperature within the manufacturing facility. 

Since there are not many materials that go into the creation of wood-fiber ICFs, the production of the woodcrete blocks is fairly simple. Now, of course, each company may have its own process of creating its product, but they are roughly similar.  First, they source softwood, break it down with an industrial grinder to then be left with chippings, which are then graded and assessed for precise graduation. After it passes the grading process it is then mineralized and mixed with cement. A block machine shapes the mixture, after molding they are laid out on the floor to dry (for Durisol, this is also where the blocks are covered with polythene for curation), once dried, the blocks are then put through another machine where they get trimmed top and bottom and framed for the cement placement, later on. The woodcrete ICFs are then packaged and shipped out. With these blocks, we can build sustainable structures such as houses, schools, etc. You can find these blockers being manufactured in Europe, North America, and possibly some other nations as well. With ICFs in general, “North America currently dominates the market for insulated concrete forms followed by Europe and APAC. The developing regions of South America and Asia Pacific are expected to increase its market share in the future owing to the growing construction activity in the developing countries.”(Global insulated concrete form market - growth, trends and forecasts to 2022). When it comes to transporting the blocks, for shorter journeys, the blocks are typically stacked in bundles and transported through semi-trailers. Although I couldn’t find sources on how they would be transported across lands, for longer journeys, such as crossing continents, or bodies of water, I would assume cargo ships would be used.

When researching the construction process for building a structure with wood-fiber ICFs, most sources covered the process broadly, Durisol was the only one I came across that gave a few more specific details. In their process, they start with the corners then create the rest of the parameters. The blocks are dry-stacked and after the first two layers, filled with cement. A damp proofing goes on, then the stacking of the blocks continues while the cavities get filled every 4 feet or so. The broad consensus is that the blocks are dry-stacked and filled with cement. Since it is still a fairly new system, structures created with these ICFs are still intact and in use. ICFs in general have a long lifespan, therefore information on deconstruction is inconclusive. In terms of disassembling, since concrete is poured into the block cavities, I don’t believe it can be disassembled either. If there is no conclusive information on deconstruction and disassembly, then can the blocks be recycled? As of right now, it doesn’t look like it can, but the blocks themselves are already made up of recycled material, so this is already a step ahead of some building processes, and possible recycling solutions post-construction may include repurposing the structure. If the blocks were recyclable, possible solutions for deconstruction may include pulverizing the cement for reuse.

Wood-fiber ICFs may be a low-carbon alternative for building material, but it also possesses many benefits for the structure being built. First and foremost, the mineralization of the wood chippings makes the wood fibers fire-resistant, termite-proof, and unsusceptible to rotting. The block itself does not suck in moisture, due to this, construction can take place regardless of weather conditions. The blocks are breathable, adaptable, and easy to cut, which allows for architectural flexibility and alternative exterior finishes. When constructing, the concrete-filled cavities provide insolation to the completed structures. Since the blocks incorporate recycled materials, it utilizes local resources and provide an affordable way of building.

Woodcrete insulated concrete forms are used to construct structures and provide a fireproof renewable alternative to traditional building methods. Although it may have been predominant in Europe, we can now see it being adopted in other nations as well. Woodcrete ICFs, containing many benefits, can be found in multiple locations and is a growing resource.

Materials - Bibliography

Aigbomian, Eboziegbe Patrick, and Mizi Fan. "Development of Wood-Crete building materials 

from sawdust and waste paper." Construction and Building materials 40 (2013): 361-366.

Bioinspired struvite mineralization for fire-resistant wood. ACS Publications. 

https://pubs.acs.org/doi/abs/10.1021/acsami.8b19967?casa_token=69zolNeiL2AAAAAA%3A49GaBrhg5d3ZhmtXe0OyKgkTB7jsQcUoTDK23oLD375Q7SVIf7k6O2ZgmYkPe69LCBQfn0CDEyaZaKU. 

Coutts, R. SP, and A. J. Michell. "Wood pulp fiber-cement composites." J. Appl. Polym. Sci.: 

Appl. Polym. Symp.;(United States). Vol. 37. No. CONF-8205234-Vol. 2. CSIRO Division of Chemical and Wood Tech., Clayton, Australia, 1983.

Flörke, Otto W., et al. "Silica." Ullmann's Encyclopedia of Industrial Chemistry (2000).

Garth, John Stuart. Experimental investigation of lateral cyclic behavior of wood-based 

screen-grid insulated concrete form walls. Diss. Portland State University, 2014.

Global insulated concrete form market - growth, trends and forecasts to 2022 - research and 

markets. Global Insulated Concrete Form Market - Growth, Trends and Forecasts to 2022 - Research and Markets | Business Wire. (2017, September 11). Retrieved December 1, 2021, from https://www.businesswire.com/news/home/20170911005501/en/Global-Insulated-Concrete-Form-Market---Growth-Trends-and-Forecasts-to-2022---Research-and-Markets. 

Guo, Huizhang, et al. "Struvite mineralized wood as sustainable building material: mechanical 

and combustion behavior." ACS Sustainable Chemistry & Engineering 8.28 (2020): 10402-10412.

Hahn, Frederick C., Maurice L. Macht, and David A. Fletcher. "Polythene Physical and 

Chemical Properties." Industrial & Engineering Chemistry 37.6 (1945): 526-533.

Mustoe, George E., and Graham Beard. "Calcite-Mineralized Fossil Wood from Vancouver 

Island, British Columbia, Canada." Geosciences 11.2 (2021): 38.

Merk, Vivian, et al. "Mineralization of wood by calcium carbonate insertion for improved flame 

retardancy." Holzforschung 70.9 (2016): 867-876.

Nexcem, from https://nexcembuild.com. 

Pehanich, Jennifer L., Paul R. Blankenhorn, and Michael R. Silsbee. "Wood fiber surface 

treatment level effects on selected mechanical properties of wood fiber–cement composites." Cement and concrete research 34.1 (2004): 59-65.

Shand, Mark A. The chemistry and technology of magnesia. John Wiley & Sons, 2006.

Woodcrete ICF: Durisol ICF: Cost-effective, sustainable build. Durisol UK. (2019, February 12). 

Retrieved October 22, 2021, from https://www.durisoluk.com/icf-technical-advice/what-is-woodcrete-icf/.

YouTube. (2021). An Introduction to Durisol Woodcrete Icf for Developers. YouTube. Retrieved 

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https://www.youtube.com/watch?v=YmBuBf5lvDM. 

Energy:

Goldschneider, Isadora

Group: Afrah Said, Gabriel Bruce

Professor Cogdell

November 18, 2021

Energy Inputs for Wood Fiber Insulated Concrete Forms

Wood-Fiber Insulated Concrete Forms are marketed as energy efficient building materials for “high performance” homes. They are made from recycled woodchips that are mineralized and set with concrete into an insulated mold shape, into which concrete is poured. The energy input in the production of wood-fiber ICF’s comes in many phases and can generate harmful greenhouse gasses. Fossil fuels are required to extract and transport concrete aggregates, and the thermal energy needed to heat Portland cement to approximately 1500 degrees C, a necessary ingredient in concrete, is achieved by burning fossil fuels as well as industrial waste, contributing to greenhouse gases. The design of Faswall, one of the two wood-fiber ICF manufacturers in North America, is such that the amount of concrete used to create an insulated form is as low as 15%, with 85% of the block consisting of recycled and mineralized wood. Reducing the amount of concrete used in construction is beneficial for the environment considering concrete’s energy intensive production. Throughout its lifecycle, from extraction of raw materials through the creation of concrete to the manufacturing of wood-fiber ICF’s to the efficiency and longevity of the buildings, wood fiber insulated concrete forms rank as high performance for their energy efficiency. 

Although wood fiber ICF’s are considered a high-performance building material, the energy required for extracting primary and secondary raw materials and their transportation rely heavily on fossil fuels. Energy goes into extracting the raw materials of concrete, calcareous and argillaceous, or other silica-, alumina-, and iron oxide-bearing. Mining for limestone and aggregates, an extractive industry, are destructive for the environment, polluting water and destroying ecosystems. “According to National Stone, Sand and Gravel Association (NSSGA), and the Natural Stone Council (NSC), major energies used in mining and processing of limestone are electricity, coal, gasoline, natural gas, liquid fuel, and renewable energy (Mbah, 1)”. The energy used to process and transport industrial waste used for secondary raw materials in ICF production, including slag from steel production that is used in cement, and waste from the timber and construction industries also rely on fossil fuels. “Blast furnace slag (BFS) is the residue and solid waste from iron/steel metallurgical industry, whose storage not only occupies a large amount of land resources but also causes environmental pollution to the soil, underground water and atmosphere (Li, 221)”. Fly ash is a byproduct from chemical reactions during the burning of coal for electricity which are used in cement production. 

Energy required for cement production is where most of the embedded energy lies in wood fiber ICF’s, a process which relies heavily on fossil fuels. Intensive energy is required to heat a mixture of limestone and shale in a kiln to a temperature of approximately 1500 degrees Celsius to create clinker. To reach this temperature, a massive amount of fossil fuels use is required, and the industry will burn industrial waste, to produce thermal energy and keep the cost of their cement low. Although cement has high embedded energy due to all these factors, the amount of cement used in wood fiber ICF blocks is quite low, only 15% of the mix in Faswall. Recycled wood makes up 85% of the product Faswall, one of the major ICF manufacturers. Recycled wood collection and processing entails transporting wood waste to a wood waste recycling plant, diesel for handling of the wood waste within the recycling plant and electricity for crushing and sizing wood waste to produce smaller wood aggregates.

The energy required for wood fiber ICF’s manufacturing includes mineralizing recycled wood aggregates which makes the woodchips comparable to crushed stone aggregates in concrete. It was difficult to find what woodchips are mineralized with, since companies such as Faswall market this step as a “proprietary process”, however I found an article which describes the mineralization of wood as soaking the woodchips in bypass cement kiln dust to make them inert, “the principle of wood mineralization, i.e. a natural phenomenon, which is generally based on the deposition of mineral substances that can partially or completely replace organic substances (Majstrikova 1).” In this example, wood chips are dipped in demineralized water that is mixed with bypass cement kiln dust and kept at 20 degrees Celsius at the atmospheric pressure of ≅ 100 kPa for up to 180 minutes. They are surface dried by applying filter paper. Manufacturing mineralized wood for wood fiber ICF’s require electricity for temperature/atmosphere regulation, as well as electricity for indoor equipment to move wood chips before and after mineralization. The wet mineralized wood is transferred to a blocking machine which also runs on electricity, where the blocks are created, and allowed to dry under specific atmospheric conditions. They do not require to be fired in a kiln like regular concrete blocks. Wood fiber ICF blocks are manufactured to order, from one of two manufacturers, Faswall in Oregon or Durisol in Canada (now Nexcem) and delivered by truck to the building cite. The efficiency of manufacturing to order reduces transportation cost, since the product is made and shipped directly to the building cite, cutting out the distributor.  Transporting cement and wood fiber to the manufacturing cite and transportation of the completed ICF blocks require fossil fuel energy. 

Benefits of building with wood fiber ICF blocks are the ease in which they can be built, due to their relatively light weight, interlocking tongue and grove design, the blocks can be stacked dry by hand onto horizontal and vertically stacked rebar which is then filled with concrete. This creates a grid like effect that is very strong with minimal steel and less concrete than an average concrete wall, and relatively quick.  Faswall wood fiber ICF blocks weigh approximately 30 pounds, making animate prime movers the primary energy source in construction. The energy required for the building phase of a wood-fiber ICF building relies on human labor, electricity for power tools and fossil fuels for transportation of materials, including the concrete truck for pouring concrete into the molds. Wood fiber ICF walls are designed such that less energy is expended at the construction site than timber frame homes. 

Energy efficiency, durability and longevity are some factors that get wood fiber ICF’s into the sustainable building materials category. With an R value from 21-25, wood fiber ICF homes benefit from passive solar heating by absorbing heat from the sun during the day that gradually radiates into the building’s interior during the day. There are building methods that can increase the R-value to 30, such as adding polystyrene foam to the outside of the building. The wood fiber ICF manufacturer Faswall claims that homes built with their product can last up to 200 years due to mineralized wood’s anti-microbial properties, which are vapor-permeable, are of hygroscopic nature and do not allow mold spores to grow within the walls. If a home can withstand weather for as long as 200 years compared to a timber frame home which requires routine maintenance to combat moisture damage and mold over the course of 30 to 100 years, the energy savings are considerable. In the life span of a wood fiber ICF building, a timber frame building of its same size would need to be repaired or demolished and rebuilt. A high fire rating of 4 hours means that buildings made with wood fiber ICF’s are more defensible against wildfire which is a growing concern with climate change. Durability against moisture makes this an ideal building material for flood prone areas. All these factors improve the performance of the building material, reducing the energy needed to operate and maintain the home. 

The embedded energy in wood fiber ICF blocks is high due to the raw material acquisition and the manufacturing process of the concrete but compared to the building’s life span and its energy efficiency, durability and high insulation properties, this building material is considered sustainable and economic. A designed material such as wood fiber ICF’s helps to reduce the amount of unused waste from other industries such as timber and steel, while reducing energy consumption over centuries. Further increasing the energy efficiency of concrete production and minimizing the quantity in which concrete is used will continue to help reduce the impact of building construction on the environment.

Energy - Works Cited

Aigbomian, Eboziegbe Patrick. Development of wood-crete building material. Diss. Brunel University, 2013.

Amiri Fard, Farhad, et al. “Comparative Assessment of Insulated Concrete Wall Technologies and 

Wood-Frame Walls in Residential Buildings: a Multi-Criteria Analysis of Hygrothermal Performance, 

Cost, and Environmental Footprints.” Advances in Building Energy Research, vol. 15, no. 4, Taylor & 

Francis, 2021, pp. 466–98, doi:10.1080/17512549.2019.1600583.

Berger, F., et al. “The Recycling Potential of Wood Waste into Wood-Wool/Cement Composite.” 

Construction and Building Materials, vol. 260, 2020, p. 119786. Crossref, 

doi:10.1016/j.conbuildmat.2020.119786.

Chandra, Satish. Waste materials used in concrete manufacturing. Elsevier, 1996.

Durisol UK. “Product Safety Data Sheet Issue Date April 2018 - Durisol UK.” Durisol UK, Apr. 2018, https://www.durisoluk.com/app/uploads/2018/04/Durisol-SDS-Sheet-V-10.0-APR18.pdf. 

Falk, Bob. "Wood Recycling: Opportunities for the Woodwaste Resource." Forest Products Journal, vol. 47,

no. 6, 1997, pp. 17-22. ProQuest, https://www.proquest.com/scholarly-journals/wood-recycling-opportunities-woodwaste-resource/docview/214627739/se-2?accountid=14505.

 Glenn, Jim. "Wood Residuals Find Big Uses in Small Pieces." Biocycle, vol. 37, no. 12, 1996, pp. 35-38. 

ProQuest, https://www.proquest.com/trade-journals/wood-residuals-find-big-uses-small-pieces/docview/236881471/se-2?accountid=14505.

  Hossain, Md. Uzzal, and Chi Sun Poon. “Comparative LCA of Wood Waste Management Strategies Generated from Building Construction Activities.” Journal of Cleaner Production, vol. 177, Elsevier Ltd, 2018, pp. 387–97, https://doi.org/10.1016/j.jclepro.2017.12.233.

Hornby, Rachelle. "A Review of Alternative Building Materials in comparison to CMU: Hempcrete, Woodcrete, Papercrete." (2017).

“Intro to ICFS and Alternative ICFS.” ICF Builder Magazine, 7 July 2021, https://www.icfmag.com/2021/07/intro-to-icfs-and-alternative-icfs/. 

  Lea, F. M. (Frederick Measham), and P. C. Hewlett. Lea’s Chemistry of Cement and Concrete. Fourth edition / edited by Peter C. Hewlett., Arnold, 1998.

  Li, Yao, et al. “Environmental Impact Analysis of Blast Furnace Slag Applied to Ordinary Portland Cement Production.” Journal of Cleaner Production, vol. 120, Elsevier Ltd, 2016, pp. 221–30, doi:10.1016/j.jclepro.2015.12.071.  

Majstrikova, T., et al. "Mineralization of wooden elements by bypass cement kiln dust." IOP Conference Series: Materials Science and Engineering. Vol. 1039. No. 1. IOP Publishing, 2021.

Mbah, Tawum Juvert, et al. "Using LSTM and ARIMA to Simulate and Predict Limestone Price Variations." Mining, Metallurgy & Exploration 38.2 (2021): 913-926.

“No Mold - Vapor + Water in Wet Climates: Faswall ICF Healthy Blocks.” Healthy, High Performance ICF Building System | Faswall Blocks, 24 Sept. 2019, https://faswall.com/sustainable-wet-climates/. 

Riazanov, A A et al. “Resource Saving and Energy Saving at the Simultaneous Production of Two Types of Cement.” IOP Conference Series. Materials Science and Engineering. Vol. 907. Bristol: IOP Publishing, 2020. 12034–. Web. 

Sokolova, Yulia, et al. “The Study of Structure Formation and Mechanical Strength Properties of 

Sulfur-Containing Woodcrete Composites Exposed to Permanently Acting Loads.” IOP Conference 

Series. Materials Science and Engineering, vol. 869, no. 3, IOP Publishing, 2020, p. 32005–, 

doi:10.1088/1757-899X/869/3/032005.

Taranth, S D. “Unit 2 Binding Materials - Wordpress.com.” Wordpress.com, Alliance University, 2016, 

https://allbtechblog.files.wordpress.com/2016/08/unit-2-binding-materials.pdf. 

Weeks, Jennifer. "BIOBASED MATERIALS TEAM UP WITH RENEWABLE POWER."Biocycle, vol. 46, no. 

12, 2005, pp. 46-49. ProQuest, https://www.proquest.com/trade-journals/biobased-materials-team-up-with-renewable-power/docview/236921793/se-2?accountid=14505.

WBCSD-CSI (World Business Council for Sustainable Development e 

Cement Sus- tainability Initiative), 2009. Cement Technology Roadmap: 

Carbon Emissions Reductions up to 2050. http://www.wbcsdcement.org/pdf/technology/WBCSD-

IEA_Cement %20Roadmap.pdf.

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International Conference on Sustainable Buildings and Structures (Suzhou, P.R. China, 29 October - 1 November 2015) (1st ed.). CRC Press. https://doi.org/10.1201/b19239

Waste:

Bruce, Gabriel

Group: Afrah Said, Isadora Goldschneider

Professor Cogdell

December 1, 2021

Waste produced by Wood-Fiber Insulated Concrete Forms

Wood-fiber insulated concrete forms are a tremendously efficient and intuitive system for building walls in residential structures. They are compact and uniform, built for modular construction, and require significantly less technical knowhow in order to build with them than traditional wall construction techniques. However, in the more recent swell in their popularity, it has been their environmental impact which has been most widely advertised as their primary feature. Compared to their polystyrene counterparts, this is not a stretch, and the exploration of alternatives to that and other fossil fuel based materials is a tremendous boon to more environmentally friendly construction. However, the advertised veneer of a completely non-toxic new solution is inaccurate, both in its newness and in its impact on the environment. 

To understand these claims and their reality, it's helpful first to understand the makeup and history of ICFs. Insulated Concrete Forms are fundamentally modular molds for concrete. They are built out of some sort of lightweight material and come in hollow brick like forms that when stacked like legos make up a hollow wall that can then be filled with concrete. These bricks also are built with insulated linings provided the insulation needed for interior construction. According to Robert J. Pierson from Green Harbor Building Systems, ICFs were first “developed in Belgium in 1937 by the Swiss nationals August Schnell and Alex Bosshard”, founding Durisol AG the following year. Not long after they found great success with the end of WWII in the growing need of quick domestic construction with largely unskilled labor. These ICFs were made from wood fibers, bonded with cement. The company Durisol UK has endured until this day producing wood-fiber ICFs for over 80 years(Pierson). 

Contemporary use & marketing:

But most ICFs distributed today, especially in the US, aren't built from cement bonded, mineralized wood-fiber. Instead, the majority of ICFs on the market are made out of the lightweight and cheaper polystyrene. As also described by Pierson on Green Harbor Building Systems website(a manufacturer of polystyrene ICFs), Polystyrene is a chemically produced clear plastic that when baked produces a white foam, known as expandable polystyrene foam. This foam is in of itself a great insulator, and in the late 1960s the contractor Werner Gregori was inspired to build ICFs out of the insulating material thereby alleviating the need for built in or up insulation within/on top wood-fiber ICFs. Polystyrene ICFs have since took off and become quite common. Because it is so lightweight and easy to order, they have also become a go to for consumers who wish to build their own homes. 

However, Polystyrene is a plastic, and in its foam form it poses many of the same problems the fossil fuels it was made from do: significant toxicity made worse by its high flammability. Fire retardants are now often used to reduce fire risks in these products, but they notoriously make them even more toxic. Today with green design in vogue and sustainability on the minds of consumers, returning to ICFs made of not only organic matter, but organic waste seems like a logical next step.

A few companies actively producing Wood-fiber ICFs include Durisol UK, Nexcem, and Fastwall. All of the above advertise their sustainability, Durisol UK stating first on their website “Durisol woodcrete ICF blocks are the simple and sustainable alternative”, Fastwall’s stats “Healthy, High Performance ICF Building System”, and Nexcem’s site simply states “superior design by nature”. While claiming that your highly specific construction system is ‘designed by nature’ might be a stretch, it makes sense that the market for woodcrete ICFs are making a clear differentiation between their products and the plastic foam products currently dominating the market. Regardless of their competition, these products are not entirely green, and in fact produce significant and dangerous waste emissions in their life cycle from materials to manufacturing to the construction and maintenance of a home. 

Extraction and processing of raw materials:

Wood Fiber ICFs waste impacts start in their raw materials. The primary and most advertised material is the wood fiber that contributes to the body of the ICF. Wood, from trees, is a carbon sink, and therefore reduces the carbon from the atmosphere and the impact of the final product. According to a study by ACS Sustainable Chemistry & Engineering, wood can store “nearly one ton of CO2 per cubic meter”(Guo, Huizhang, et al., p. 01). This effect is further accentuated by the source of most wood fiber for ICFs coming from wood waste. This displaces waste that would otherwise end up in landfills or be incinerated releasing all of that previously captured carbon. The impact of these two facets are undeniable and contribute greatly to the benefit of this construction system, but the retrieval of wood-fiber is far from the final step and is unfortunately the last carbon negative one in the progression to the construction and end of life of these products.

Next, wood-fibers, often in the form of wood-chips, must be alleviated of one of the same drawbacks that Polystyrene faces: flammability. To reduce combustion and increase charring, wood-chips are mineralized, a process of impregnating the wood fiber with a variety of fire retardant chemicals under various conditions of temperature and vacuum. While the chemicals used vary from company to company, common chemicals used include magnesium sulfate(MgSO4), potassium dihydrogen phosphate(KH2CO4), and Ammonia gas (NH4) among others(Guo, Huizhang, et al., p. 02). According to the same study by ACS Sustainable Chemistry & Engineering, these chemicals are known to be released from finished ICF products and can cause significant environmental and health concerns(Guo, Huizhang, et al., p. 01).

Next, the mineralized wood-fibers must be bound together and molded to form the structure of the ICF brick, this is done with portland cement. Portland cement, a component of concrete, is widely known to be incredibly environmentally costly with the waste that it produces. The process of extracting stone, grinding, heating, and compressing it requires an incredible amount of energy. Historically cement plants have used vast amounts of coal to power their production process. Recent controversies have motivated the industry to find alternatives, one of which has been in the burning of waste tires, which in of its self releases great quantities of toxic gasses into the air. Within the manufacturing process of cement, especially the ‘clinker phase’, gasses such as sulfur dioxide(SO2), nitric oxide(NO), carbon dioxide (CO2), as well as micro-pollutants of different varieties are released into the air.  This is in addition to the dust, noise, heat, and incredible vibrations that the local area experiences as a result of such cement plants(CEMEX, et al., p. 10). 

Manufacturing and transportation:

The impact of cement within the construction of wood-fiber ICFs is perhaps the most significant, however waste continues with the manufacturing of the ICF blocks themselves, as well as the transportation of their raw materials and the finished products to site. All of these processes rely on fossil fuels through internal combustion vehicles or power plants. These produce carbon dioxide (CO2), the greenhouse gas most associated with climate change. 

Construction, use and maintenance:

Once wood-fiber ICFs are manufactured and delivered to the construction sites on which they are used to build houses further CO2 is released in the process of moving and sometimes lifting the relatively heavy bricks. More importantly however, the ICF finally plays its intended role. After arranged in a wall formation, the Insulated Concrete Forms are filled with concrete. Although slightly varying on the brand, the amount of concrete used is close to a third to a half of the mass of the ICF per ICF placed. This is a tremendous amount of concrete, all of which has the environmental impact of cement previously discussed, plus additional emissions for the further processing into mixed concrete. The CO2 output alone of concrete is estimated to be around 410 kg per cubic meter of concrete. 

On the construction site further waste products from the building construction process are released based on procedure and accidents. Despite the ICFs containing built in wood wool insulation, oftentimes Polystyrene panels are attached to the outside to create extra insulation, requiring further plastic and fossil fuel burning, and can lead to further waste as the house ages and panels are disposed of. As the house is constructed in the open air, the fire retardant chemicals used in mineralizing the wood-fiber will often be released and can be further activated by prolonged sun exposure. 

After the house is completed, similar small chemical leaching can occur although it is not as thoroughly researched. Similarly, the deconstruction of houses built with these materials, despite their long history, is also lacking in academic study. 

Conclusion:

Wood fiber ICFs are an incredible improvement on polystyrene alternatives, however the fundamental use of concrete, and the use of other harsh chemicals to address fire retardancy concerns jeopardize the validity of this construction system as an environmentally friendly option. There is no way at this time for concrete and cement to be used in a green way, and to market the product as otherwise is misleading. However the use of wood and wood-waste products is a positive and should be used as a standard to strive for on all levels of a technologies development and manufacturing. 

Waste - Bibliography 

“British-Made Sustainable, ECO Friendly Woodcrete ICF | Durisol.” Durisol UK, 12 Oct. 2021, 

www.durisoluk.com.

CEMEX, et al. “The Cement Sustainability Initiative - Our Agenda for Action.” 

Web.Archive.Org, World Business Council for Sustainable Development, 2002, web.archive.org/web/20070714085318/http://www.wbcsd.org/DocRoot/1IBetslPgkEie83rTa0J/cement-action-plan.pdf

Guo, Huizhang, et al. "Struvite mineralized wood as sustainable building material: mechanical 

and combustion behavior." ACS Sustainable Chemistry & Engineering 8.28 (2020): 10402-10412. 

“Nexcem - Insulated Concrete Forms (Canada and the US).” Nexcem, 4 Dec. 2021, 

nexcembuild.com.

Pierson, Robert. “History of Insulated Concrete Forms ICF’s - Best since 1966 - GH Building 

Systems GA.” Http://Www.Icf-Green-Building-Systems-Ga.Com/, Green Harbor Building Systems GA, , www.icf-green-building-systems-ga.com/insulating-concrete-forms-green-building-materials-information-georgia/history-of-insulated-concrete-forms.html.

Salvia, Vanessa. “Efficient and Affordable ICCF Family Home.” Healthy, High Performance 

ICF Building System | Faswall Blocks, 29 July 2021, faswall.com.