The joist was the beam that held up the floor. A length of wood running from wall to wall under the floorboards. You could not see the joist. You walked on the floor and the floor walked on the joist and the joist carried everything. Every piano and every bathtub and every argument that happened in the apartment sat on the joists. The joist did not care what happened above it. The joist just held.

The joist was sized. That was the engineering. A joist for a bedroom was a two-by-eight. A joist for a parlor was a two-by-ten because the parlor was wider. The carpenter measured the span and picked the lumber and the lumber carried the load and the load was people living their lives without thinking about what was under them. You do not think about the joist until the floor bounces. A bouncing floor is a joist asking for help.

The joist creaked. Every old building in New York had joists that creaked because the wood dried out and shrank and the nails loosened and the joist moved a sixteenth of an inch every time you stepped on it. The creak was the joist talking. The creak said I have been here a hundred years and I am still here and I will be here when you are gone. The engineered floor does not creak. The engineered floor is silent. Silence from a floor is not confidence. Silence from a floor is amnesia.

You could read a joist. A carpenter looked at the end grain and knew the tree. Old growth or new growth. The growth rings were tight on old growth timber and the tight rings meant the wood was strong. A joist cut from old growth hemlock in 1880 is still holding the floor. A joist cut from plantation pine in 2024 will bounce in ten years. The tree knew how long the floor needed to last. The mill does not ask the tree anymore.

They use engineered joists now. Plywood and glue pressed into an I-shape like a tiny steel beam. The engineered joist does not creak. The engineered joist does not shrink. The engineered joist is lighter and stronger and it has no story. The old joist was a tree. You could find the knot where the branch grew. You could find the stain where the tree bled sap. The engineered joist is a product. A product does not remember the forest.

See also: Cellar Stairs, Stairwell