80x120 Steel Office Building

This page is ordered around the enclosed space that supports the open floor, because focus and call rooms are what make open desking usable and are the first thing cut.

The footprint holds 30 team zones — 5 across by 6 deep — and leaves 15 feet of depth for focus and call rooms at the floor's edge, so concentrated work has somewhere to go without booking a meeting room.

Read this footprint through its span. 80 feet across is the fixed constraint; 120 feet of length is the negotiable one, and at 1.5 to 1 the building is close to square, so movement runs in both directions. Two feet of spare width reads as nothing on a plan and as a great deal when a machine is being turned.

A 80 by 120 footprint is a clearly directional plan: 9,600 sq ft enclosed by 400 ft of wall, at a 1.5:1 length-to-width proportion. Along its 120 ft dimension it takes 7 runs of team zones at 16 ft, leaving 8 ft over — the 8 ft is where the argument about this size actually happens. Taken purely as arithmetic, 80 by 120 gives 5 team zones across the 80 ft dimension once 9 ft is reserved for movement, and 7 deep along the 120 ft dimension. Run as a an open working floor with enclosed space for the work that needs it, 1 ft across is below the 10 ft this use needs to be worth planning, so there are no focus rooms, so calls happen at desks and the open floor's noise becomes its defining feature Acoustic separation is specified for the specific partitions and ceilings rather than assumed from a layout.

This footprint is planned as an open working floor with enclosed space for the work that needs it. Spent as a square 98 by 98 instead, the same 9,600 sq ft would stand 6 team zones across rather than 5, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. Compared with a 80 by 90 of the same width, the extra depth here adds run rather than reach: it buys about 7 team zones in line, and every position past the second is retrieved by moving what stands in front of it. A building of this size behaves like a small yard under a roof: zones need to be defined, signed and left alone, or they migrate. The floor is occupied all day at varying densities, so circulation and acoustic separation matter more than desk count. Daylight depth from the window line shapes where desks are worth placing.

The work pattern this floor could equally be planned around is an office of individual rooms, planned around privacy and corridors: there is no support core, so shared functions sit in the corridor and every use of them is heard through two doors. Open desking in the centre with enclosed rooms on the perimeter, keeping daylight shared rather than walled into offices.

Depth arithmetic leaves a working end zone here. 1,200 square feet sits past the last row, which is why 80x120 tends to be planned with focus and call rooms at the floor's edge, so concentrated work has somewhere to go without booking a meeting room designed in rather than added later. The plan is only as good as the route into it, which is a site question rather than a building one.

Spare width is the more valuable of the two leftovers here: a continuous 10-foot strip beats the same area stranded at the end of the run, because it touches every position along the way. Whoever operates the building daily should read the plan before it is frozen, because they know where the pinch points are.

Spent as a square 98 by 98 instead, the same 9,600 sq ft would stand 6 team zones across rather than 5, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. Compared with a 80 by 90 of the same width, the extra depth here adds run rather than reach: it buys about 7 team zones in line, and every position past the second is retrieved by moving what stands in front of it. A building of this size behaves like a small yard under a roof: zones need to be defined, signed and left alone, or they migrate. The floor is occupied all day at varying densities, so circulation and acoustic separation matter more than desk count. Daylight depth from the window line shapes where desks are worth placing. That movement pattern, not the 9,600-square-foot total, is what decides whether the leftover 15 feet is useful here.

Nominal bay division computes to 5 bays at about 24 feet, wider than the 14-foot module — so a position can sit inside a bay without a frame line splitting it. Daylight placement changes how a floor is used far more than its cost suggests.

Two-plus rows change the access question entirely. Every rear position at 80x120 needs either its own opening or an aisle, and 10 feet of spare width is what that aisle has to come from. Security and after-hours access are easier to design in the door layout than to bolt on later.

Density increases before area does, which makes the initial provision of enclosed rooms a decision about the floor's future rather than its present.

Configured as an open working floor with enclosed space for the work that needs it, 80x120 is judged on whether the 30 team zones it holds match the operation, and on whether the 10 feet of spare width leaves the route this mode depends on.

• Does the work need racking or work zones on both sides with a full vehicle lane down the middle, or does it need a second lane that this 80-foot span cannot give?
• Is the 120-foot length being bought for depth, or for the repeated bays — a long repeating bay sequence, so segment boundaries are set by bay lines rather than by walls?
• What finished ceiling height do you want, and what service zone sits above it?
• Where does the service core go, and does the desk plan work around it?

Across a 80-foot span the 4:12 pitch adds 13.3 feet between eave and ridge. The centreline measures 35.3 feet; anything parked or stacked near a wall lives with the 22-foot eave. The span is the commitment; everything inside it is rearrangeable later, and the 80-foot dimension is not.

Height affects acoustics and services distribution. Acoustic treatment is specified for the specific floor plate.

Ventilation across 9,600 square feet at this height: continuous occupancy at desk density makes air handling a core system rather than an accessory.

One opening per position works on this gable: 5 across 80 feet, with 10 feet of wall to distribute as piers. Splitting that margin evenly is what keeps the elevation buildable. Doors and their approaches decide more about daily use here than the enclosed area does.

The 80 ft ends and the 120 ft sides offer very different opening budgets: 80 ft of end wall has room for one wide opening or two modest ones, while 120 ft of side wall can carry several without the openings competing. On this plan the deciding factor is whether open plan office floor or focus and call rooms should be the first thing reached from the door.

• 50x80 moves the count from 30 to 12 team zones (3 across by 4 deep), which is the reason to choose between them.
• 40x100 moves the count from 30 to 18 team zones (3 across by 6 deep), which is the reason to choose between them.
• 60x80 moves the count from 30 to 16 team zones (4 across by 4 deep), which is the reason to choose between them.

Because this footprint is planned as an open working floor with enclosed space for the work that needs it, the useful next reads are different from the ones a differently shaped steel office building suggests: open plan office floor, focus and call rooms, daylight distribution.

Quantities, not prices, are publishable here: roof cladding runs 10,119 square feet — 5% above the 9,600-square-foot floor at a 4:12 pitch — with 177.8 cubic yards of nominal slab beneath it. The building is fixed for decades while the operation inside it changes every few years, and the plan has to survive that.

Proportion drives cost here as much as size does: 400 ft of wall around 9,600 sq ft is 0.042 ft of wall per enclosed square foot, and a squarer plan of the same area would carry less. What moves the figure further on a an open working floor with enclosed space for the work that needs it is the fit-out open plan office floor implies, along with framed openings and the height chosen for the 80 ft span.

• interior partitions, ceilings and finishes across the whole floor
• the service core with restrooms and kitchen
• air handling for continuous occupancy
• small-power and data distribution density