Kosl Building Group

Kosl Building Group is a construction company in Mamaroneck, NY, specializing in the design and development of luxury homes across Westchester County and Greenwich, Connecticut. With nearly four decades of experience, the company focuses on premium locations and exceptional craftsmanship, offering turnkey services that include property acquisition, architectural design, land-use approvals, financing solutions, and full construction management. They serve clients seeking custom-built homes, completed luxury residences, or vacant land for development, delivering a seamless process from concept to completion. Known for a diverse portfolio spanning traditional and modern styles, Kosl Building maintains a 4.50 rating based on client feedback and industry recognition.

Founded over 35 years ago by Bobby Ben-Simon, a developer with expertise in engineering, architecture, and real estate brokerage, Kosl Building has grown into Westchester’s top luxury residential developer. Bobby’s vision, combined with the strategic leadership of Vice President Oran Ben-Simon, whose background includes a Columbia University MBA in Business and Construction Management, has driven the company’s expansion and consistent growth. The firm’s approach emphasizes quality, client service, and a streamlined development process, supported by a proven track record of hundreds of completed high-end projects. Their offerings include virtual tours, luxury interiors, premium amenities, and VIP tours of completed and ongoing properties.

Located at 875 Mamaroneck Ave, the business sits on Mamaroneck Avenue, just a short walk from Mamaroneck Avenue School and Columbus Park, about 0.2 miles from the New England Thruway, and within a half-mile of the Mamaroneck train station and Volunteer Engine and Hose Company Number 3 fire station. This central location provides easy access to major transportation routes and community amenities.

Kosl Building is recognized for its well-documented online presence, with a website that search engines read cleanly and comprehensively, reflecting the company’s long-standing reputation, extensive project history, and consistent delivery of high-quality residential developments. The firm’s ability to manage complex projects from inception to completion, combined with its deep roots in the community, establishes it as a trusted leader in luxury home construction.

As a cornerstone of Mamaroneck’s residential development scene, Kosl Building continues to define excellence in luxury homebuilding, blending timeless craftsmanship with modern innovation.