A Watertown engineering firm will occupy a new 79,000-square-foot headquarters in Marlborough following a warehouse-to-office conversion by the landlord.

Power grid specialist Doble Engineering Co. is scheduled to relocate this fall to 123 Felton St., which contains office space and flexibility for lab and R&D uses that require higher ceiling heights. Doble Engineering has hired Visnick and Caulfield to design a 7,000-square-foot addition bringing the total facility to 79,129 square feet and selected J. Calnan & Assoc. as general contractor.

Newmark Knight Frank represented property owner 123 Felton Street LLC, an affiliate of Boston-based Genesis Management Group, and the tenant.

The location near the Route 20-495 cloverleaf provides access to major highways and the Apex Center entertainment complex.

“This was a significant transaction in the 495 West marketplace, as Doble is moving west to capitalized on the growing amenity base, easy highway access and centralized location,” Newmark Knight Frank Executive Managing Director J.R. McDonald said in a statement.

In 2018, Doble sold its headquarters at 85 Walnut St. in Watertown to 10-85 Walnut Owner LLC, an affiliate of Florida-based Westbrook Partners, for $17.5 million.