Human activities have disrupted the balance of nature's ecosystems and resources, leading to unsustainable levels of consumption, population growth, and urbanization. The built environment, which has the greatest material flows, contributes significantly to embodied energy. To address these issues, there is an urgent need to reduce the human footprint, live within nature's means, and promote sustainability in the built environment. Various sustainable building materials and practices are discussed, including wood wool boards, Tec Eco cement, ferrocement, and the use of recycled materials. Organic fiber materials and fillers can also be used to create carbon sinks in cementitious building materials.