Low Embodied Carbon Wallboard made with Biochar

The carbon impact of materials used in residential and commercial buildings is substantial. The building trade must urgently shift towards using materials with lower embodied carbon, or better yet, use materials that can sequester carbon over the life of the building and beyond. Drywall is used in enormous quantities and comes with a considerable carbon footprint. Cinterest has prototyped a wallboard material using biochar, organic binders and inorganic fillers (e.g., recycled glass). Biochar wallboard (BWB) could convert walls from high embodied carbon facades to large-scale, above ground carbon sinks while also potentially offering enhanced insulation, soundproofing and humidity control over contemporary drywall options. Early prototyping and peer review literature have shown that biochar can be utilized in a growing variety of building materials including concrete, asphalt, plaster and bioplastics. It can displace high embodied carbon or mined or high-cost materials such as carbon black, calcium carbonate and in our product, gypsum. The global drywall market is $45B which includes $13.57B in the US. In 2020, 26 billion ft2 of wallboard were sold using nearly 41 MMT of gypsum. Generally, drywall is sold through big box building material suppliers such as Home Depot, Lowe's or 84 Lumber. Purchases are generally made by home builders, contractors and less often homeowners themselves. Increasingly, builders, architects and homeowners are looking to build using more environmentally friendly materials to meet building standards such as LEED, Passive House and others. The benefit to using BWB goes beyond carbon sequestration. The gypsum used in wallboard comes from one of two sources: mined or synthetic. Mined gypsum, while plentiful, can leave behind degraded landscapes where erosion is common and local water bodies are negatively impacted. Synthetic gypsum comes from the smokestacks of coal fired power plants and may contain hazardous materials. Synthetic gypsum will also likely become more scarce as fossil fuel plants are targeted for retirement in order to meet emission reduction targets. Although gypsum can be recycled, both types most often end up in landfills where they produce hydrogen sulfide. The biochar in the BWB is not easily decomposed by microbes and will not emit odors in the event it ends up in landfills. It may end up being beneficial as an odor and toxin absorber. Unused or deconstructed BWB could be ground up on-site to enhance soil fertility or be used as sub-base for asphalt or as a liner for septic systems.