An Accessory Dwelling Unit (ADU) is one of the most flexible ways to expand your living space and add long-term value to your property. Whether you’re building a detached backyard cottage, converting your garage, or turning a basement into a complete living space, Biviano GC handles the entire process—from planning and permits to construction and finishing details. With decades of local experience and a strong reputation across Marshfield, Duxbury, and the South Shore, we build ADUs that are safe, comfortable, code-compliant, and designed to meet your exact goals—whether it’s rental income, family housing, or a private guest suite.