BuildZero² was created to tackle one of the largest and most overlooked sources of plastic waste in the construction industry. It builds on the proven material foundation developed at SayHay, where bio-based, home-compostable polymers were deployed at commercial scale in the FMCG sector under strict performance, hygiene, and cost constraints. That experience de-risked the materials, manufacturing, and quality control challenges that typically prevent sustainable alternatives from scaling. BuildZero² takes this validated platform and re-engineers it for construction, adapting materials to higher loads, harsher site conditions, and tighter tolerances, while enabling a closed-loop, compostable end-of-life pathway that replaces short-life construction plastics with circular, site-ready solutions.