We create a sustainable, high-performance alternative to traditional lumber made from Sargassum seaweed and recycled plastics. Sargassum rapidly grows up to ten times faster than trees and naturally sequesters carbon, giving our material a strong climate advantage. We convert these abundant waste streams into durable, isothermal, water, pest, rot, and rust-resistant building materials. Our technology reduces deforestation, lowers embodied carbon, and delivers a circular solution for construction