The 706 Mission project team celebrated a major milestone on Wednesday, November 13.

A “Final Pour / Topping Off” ceremony marked the last structural concrete pour of the project, which is expected to open next summer as the Four Seasons Private Residences adjacent to Jessie Square Plaza and Yerba Buena Gardens in downtown San Francisco.

“Today is the last of 140 pours of concrete to create all the decks of this 48-story building,”

said Senior Safety Manager Ray Ramierez, who was one of the organizers of the event.  Since August 2018, 31,000 cubic yards of concrete have been poured for the 700,000 gross square foot development, according to Webcor Concrete Project Manager Kenny Hua.

Similar to beam signings to mark the topping out of steel-beam buildings, final pour ceremonies commemorate the topping out of concrete structures.  During Wednesday’s event workers used permanent markers to sign their names on a symbolic bucket that was soon used to pour the final load of concrete.  (See image at left.) The signatures on the bucket represent all the hard work to get the project to this stage.

After everyone had signed, a crane lowered a hook so the bucket with an unfurled American flag and a fir tree could be hoisted to the top of the building.  The evergreen tree continues a tradition that can be traced to ancient Scandinavia to appease the tree-dwelling spirits displaced in the construction of timber-frame buildings.

Construction Manager Mike Poole told the crowd that today the tree has come to mean good luck for the building.  He pointed out that during World War II American flags were included in topping off ceremonies, and that tradition continues.

To date, approximately 400 Webcor Concrete Division workers have been involved in the concrete portion of the project, with about 70 concrete workers on-site on an average day.

“It’s all rebar and concrete holding up this entire building,” said Superintendent Matt Borland. “This structure was designed with concrete decks and columns, and there is no steel for the main structure of the building,” he added.

Vice President Kurt Ricci spoke proudly of the team’s progress to date: “We’re three and a half years into this project.  We have about five months left ‘til our first temporary certificate of occupancy and only seven months until the building owner wants to start moving in.”

Highrise residential buildings built by Webcor are always concrete, while office buildings tend to be structural steel, Kurt explained.

“Concrete minimizes sound transmission, which matters more in a residential building than in an office building.  With concrete, each deck is only about eight inches thick, and the underside of the deck – what we skim-finish – is the exposed ceiling in the residential unit.  A steel beam building requires about 14 or 15 inches of thickness between floors, so by the time you get up to the height of a building like this, you could lose a floor or more,” he said.

In keeping with tradition after topping out ceremonies, Webcor treated all workers to commemorative t-shirts and a catered lunch.

Others on hand for the event included representatives of the building’s ownership group.