Cosman Construction – Boulder, Colorado

About Cosman Construction

Cosman Construction is Boulder’s trusted name in custom deck building, proudly serving homeowners throughout the area with exceptional craftsmanship and personalized service. With extensive experience in the construction industry, we specialize in transforming outdoor spaces into functional, stunning retreats—using premium materials like Deckorators Voyage Decking and Fortress steel framing.

Since 2013, we’ve completed hundreds of successful projects, each one designed with precision and built to withstand Colorado’s dynamic climate. Our reputation is built on quality, integrity, and unmatched attention to detail at every stage of the process.

Founded by Boulder native Alex Cosman, we bring a local’s perspective and a homeowner’s care to every project. When you request a quote, you’ll speak directly with Alex, who personally oversees each job site to ensure a seamless, high-standard experience from consultation to completion.

Deck Building

Cosman Construction strives to be the premier Deck builder serving families across the Front Range.

Cosman Construction strives to be the premier deck builder serving families across Boulder & the Front Range of Colorado. Specializing in deck building, we utilize top-of-the-line materials such as Deckorators Voyage Composite. Our expertise in deck building ensures we meet your unique requirements with customized solutions. With meticulous attention to detail and personalized customer service, we guarantee exceptional results throughout your deck-building project.

Deckorators Mineral-Based Composite Decking with SureStone technology is the most sought-after choice due to its remarkable advantages, eliminating the need for painting or staining. Say goodbye to maintenance headaches with our low-maintenance, worry-free composites, which effortlessly maintain the timeless appearance of a natural wood deck. Trust us to guide you toward selecting the ideal decking option that aligns perfectly with your lifestyle needs.