12770 El Camino Real -- Rendering courtesy of Kilroy Realty Corp.

12770 El Camino Real -- Rendering courtesy of Kilroy Realty Corp.

Kilroy Realty Corp. of Los Angeles has begun construction on a new $45 million office building, which officials said is the first speculative construction in eight years in San Diego’s Del Mar Heights submarket.

The 74,895-square-foot Class A building is set for completion in the fourth quarter of 2015, on a four-acre site at 12770 El Camino Real at Townsgate Drive. It will be the third building at The Heights at Del Mar, a 219,000-square-foot office campus that Kilroy acquired in 2013.

Officials said the new three-story building, designed by the architecture firm Gensler, is being developed to LEED Gold sustainability standards. It will include floor-to-ceiling glass, a top-floor balcony and indoor/outdoor workspaces.

The campus currently includes a fitness center, golf simulator and outdoor amphitheater. Brokerage company Cassidy Turley has been hired to handle leasing at the new building.

Kilroy Realty Corp. (NYSE: KRC) is a 65-year-old company that oversees a 13.5 million-square-foot portfolio of commercial properties, primarily on the West Coast. The real estate investment trust is among the largest holders of office properties in San Diego County.

San Diego officials are currently considering Kilroy’s plans for One Paseo, a $650 million mixed-use development planned for a site at Del Mar Heights Road and El Camino Real, adjacent to The Heights at Del Mar.