Who Builds a Tower (trades by floor)

A tower is built from the bottom by a relay of trades, and every trade on this list is a program at VoTechWorks. Read it as a curriculum.

Below grade

The surveyor sets control and stakes the lines. Heavy-equipment operators excavate; pile drillers and caisson crews reach bedrock. Ironworkers tie the rebar mat; carpenters build the perimeter forms; the concrete crew pours the foundation in one night (see The 3 a.m. Concrete Pour). Waterproofers wrap the basement; plumbers set the site drainage and the sump.

Ground floor

Masons build the lobby walls; glaziers set the storefront; electricians bring in the service entrance and build the main switchgear room; fire-sprinkler fitters set the riser and the fire pump; elevator mechanics build the pits.

The core

The concrete core climbs on a jump form, a floor every three or four days; ironworkers place its reinforcement. Inside the core, elevator mechanics set rails and machines; electricians run the risers; plumbers stack the drain and supply lines; HVAC crews build the shafts; telecom technicians pull the fiber riser.

The typical floor

Ironworkers place the steel deck; welders make the connections; the concrete crew pours the slab. Glaziers hang the curtain wall. Then the fit-out: drywall, electricians (branch circuits), plumbers (restrooms), HVAC (ducts and terminal units), fire-alarm technicians, painters, flooring, millwork. The same sequence repeats sixty times.

The mechanical floor

Chillers, boilers, air handlers, pumps, transformers, generators: HVAC technicians, industrial-maintenance technicians, electricians and controls technicians build the building's engine room, usually twice — one low, one high.

The roof

Roofers lay the membrane; the crane operator dismantles the tower crane from the top down; riggers install the window-washing rig.

After the ribbon

The building engineer runs the plant. The elevator mechanic returns every year for the inspection. Housekeeping, the front desk, the dry cleaner's linen run, the data-center technician in the basement, the fire inspector: the tower employs trades for its whole life.

Count them: more than thirty programs. A tower is a school with floors.