KOSL Building Group is an established residential development firm, focusing on luxury residences in Westchester County, New York, and Greenwich, Connecticut. With decades of experience, KOSL offers a holistic development process that supports customers from concept formation to move-in completion Known for their high building standards and personalized service, KOSL’s prominent reputation in the luxury home market has been consistently upheld for nearly 40 years.

KOSL Building has drastically transformed dozens of communities throughout the most affluent districts of Westchester County, including Scarsdale, Rye, Larchmont and many others. The company goes beyond just building houses, creating estates for longevity that blend exquisite craftsmanship with lifestyle alignment. From early planning and design to final building details, KOSL’s full-service offerings ensure an enjoyable experience. Whether customers want a personalized home or a ready-to-move into property, the company's extensive portfolio has solutions that meet a wide range of needs. With continual dedication to quality work and attentive customer service, KOSL brings every customer's vision to reality.

The industry leader has completed over 250 luxury homes and won countless awards over the years, establishing itself as one of the top high-end developers in the region. Each project illustrates KOSL’s dedication to intricate design, practical layouts, and lasting quality, all of which is oriented around customer satisfaction. This effort has solidified KOSL's position as a trusted frontrunner in the residential sector.

KOSL operates as a fully integrated business with three major divisions that are KOSL Building, KOSL Realty, and KOSL Consulting. These teams work closely to offer a complete development process from start to finish. By handling every step, KOSL reduces delays, maintains high quality standards, and offers customers with a clear, trustworthy development experience.

A Seamless, All-Inclusive Development Process

One of KOSL Building Group's major benefits is its completely integrated approach to building homes. Rather than focusing on just one part of the process, KOSL acts as an entire development partner, supporting customers from the first phases of planning to final completion. KOSL handles every element of the project. This includes site planning, structural work, finishes, and managerial coordination until final completion. Each step is closely monitored to ensure quality, safety, and accuracy. The company's direct approach allows it to maintain high standards and ensure that each home sustains its long-term efficiency and quality.

KOSL Realty, the business's exclusive brokerage section, plays a key role in finding and buying premium properties. KOSL Realty, a boutique real estate firm that focuses on securing top tier properties through a process of heightened scrutiny and developer diligence. Its staff evaluates opportunities from both a broker and a builder perspective, providing keen insight on aspects often overlooked by standard brokerages. This knowledge allows KOSL to identify strong locations, evaluate development feasibility, and create new opportunities esoterically.

KOSL Consulting supports both divisions by offering strategic guidance on development planning, financial structuring, and regulatory approvals. KOSL Consulting helps to avoid delays and reduce risk by handling planning requirements, development approvals, and financial options at early stages. This proactive preparation yields heightened transparency and successful outcomes.

KOSL fills the gap between architects, builders, brokers, and consultants by combining these services as a consolidated asset. Whether a customer begins with vacant property, architectural blueprints, or previously approved plans, KOSL ensures that all details are addressed and syndicated.

Navigating Market Change with Experience and Insight

Economic conditions, changes in regulations, and world events all have an effect on the luxury real estate market. To succeed in these situations, more than just experience, planning, flexibility, and decisiveness are required. Oran Ben-Simon, Vice President of KOSL Building Group, highlighted that each market cycle has unique challenges. As new circumstances inevitably arise, the key to navigate various obstacles is an adaptive road map. This approach has helped KOSL both mitigate and manage decades of economic changes, regulatory reforms, and times of uncertainty.

Oran describes the complex nature of real estate development as a "multitude-of-levels," where compounded knowledge and critical thinking foster professional resilience. From navigating legislative and zoning reform to evolving market demands, KOSL’s distinguished performance is attributed to years of experience, allowing the organization to overcome new situations in a realistic and effective manner.

Luxury Homes Designed for Everyday Living

Building a home is one of the most monumental investments anyone can make, both financially and personally. With so many decisions to be made, ranging from the right property to the perfect aesthetics, working with a trusted construction company is fundamental. Versatility is an important component when selecting the right building partner, as it ensures flexible accommodation. KOSL Building has a vast portfolio of completed projects with designs extending from traditionally classic estates to modern residences, illustrating their ability to meet a wide range of custom needs while maintaining high quality performance. KOSL’s consistent reliability for building homes that blend attractive design with useful function while delivering unwavering client engagement has awarded them with this trusted reputation.

Every KOSL home is built with careful attention to detail. Layouts are created with thoughtful flow and functionality, and materials are selected for their durability and aesthetic value. Rather than following temporary fads, KOSL stresses timeless design that remains relevant throughout cyclical trends.

Customer service is a core value of the company. KOSL provides a personalized process that allows customers to prioritize their needs without compromise, allowing homeowners to enjoy their experience while remaining confident in the final result.

Carrying the KOSL Legacy Forward

KOSL Building Group is defined not by showy branding, but by consistent success and lasting results. The business's ability to support customers from buying a property to building completion has earned it a strong track record in luxury home development. As KOSL expands and grows, its impact on Westchester County, the Hudson Valley, and Greenwich remains significant. Each project shows the business's dedication to quality, attention to detail, and lasting value.

With Bobby Ben-Simon and Oran Ben-Simon leading the way, KOSL's future is linked to its past, built on trust, skill, and a desire for excellence. As the journey continues, KOSL stays dedicated to building houses that improve customer’s quality of life and stand the test of time.

Bobby Ben-Simon |  President

Bobby Ben-Simon is the Founding President of KOSL Building, who aimed to become the trusted residential builder the company is recognized for today. With years of expertise in engineering, architecture, and real estate development, Bobby established a business focused on steady development, outstanding construction, and a strong emphasis on customer satisfaction.

Oran Ben-Simon | Vice President

Oran Ben-Simon, KOSL Building Group's Vice President, has significantly enhanced the thriving business through project expansion, portfolio diversity, and brand development activities. Having extensive experience in business and construction management from a young age, Oran continues to work closely with Bobby Ben-Simon to advance KOSL's expansion and steady growth in the world of luxury residential development.

“KOSL Building provides a seamless, start-to-finish construction experience. Their turnkey services—including property acquisition, design planning, land-use approvals, financing, and construction management ensure a streamlined and stress-free process for every client.”