Second Key was founded by New York City real estate developers who know firsthand how stressful and expensive construction can be. As real estate experts and licensed general contractors, we simplify the process for homeowners who want to create beautiful second homes on their unused land. We take pride in finding creative and innovative ways to maximize the value and utility of our clients’ properties.

With decades of experience, we deliver quality work the right way - on time, on budget, and with no surprises. We are an ADU general contractor that specializes in building detached, backyard ADUs in Staten Island, Queens, Brooklyn and the Bronx. Our ADU construction services are designed to provide a simple, efficient, cost-saving solution for property owners interested in building an ADU on their property.