100x120 Commercial Steel Building

No price appears on this page. The quantities that scale an estimate at 100x120 are 12,000 square feet of slab, 148.1 cubic yards of nominal concrete, 6,160 square feet of wall cladding and 12,369 square feet of roof cladding. The building is fixed for decades while the operation inside it changes every few years, and the plan has to survive that.

The finished office area carries a much higher fit-out rate than the storage floor, so the office share of the footprint moves the estimate more than the total area does.

• the public elevation and its glazing
• interior partitions for tenant subdivision
• restroom and service cores
• parking and site work at the front

This page is ordered around access, because on a 100-foot endwall the opening arrangement settles how a commercial building at 100x120 is actually used.

The footprint holds 12 storage bays — 4 across by 3 deep — and the remaining 10 feet is marginal: there is no staging zone, so assembled orders occupy the loading area and block it during the busiest hour.

Commitment first: 70% of the 12,000 square feet goes to storage bays at 704 square feet each, and 2,440 square feet survives as edge strip. A footprint is worth its own decision when that split lands where the work does. Two feet of spare width reads as nothing on a plan and as a great deal when a machine is being turned.

A 100 by 120 footprint is a mildly directional plan: 12,000 sq ft enclosed by 440 ft of wall, at a 1.2:1 length-to-width proportion. Along its 120 ft dimension it takes 3 runs of storage bays at 32 ft, leaving 24 ft over — the 24 ft is where the argument about this size actually happens. This mode is really two buildings in one shell, joined at a boundary that has to be drawn deliberately. The office needs quiet, daylight and a visitor route; the warehouse needs height, hard floor and vehicle access. The plan is judged on how cleanly it keeps those two from interfering. A commercial shell outlives its first occupier, so the plan is partly written for a tenant nobody has met.

At 100x120 the operating question is a specific one: what share of this footprint should be finished office, and where does the boundary between quiet and loud sit? That is a different question from the one a commercial building of another shape has to answer, and it is why this footprint is planned as an office front with a warehouse floor behind it rather than as generic covered area.

The 100-foot gable can carry 4 openings, one per storage bay, with 12 feet of wall left for piers between and beside them — the arrangement that keeps each position independently reachable. Doors and their approaches decide more about daily use here than the enclosed area does.

Three door types with three purposes: a visitor entrance that never sees a pallet, a goods opening sized for the handling equipment, and a staff door that avoids both. Combining any two of them is a false economy.

Deliveries arrive at a rear or side opening and travel through service space, never through the public area.

At 24-foot nominal bays the structure works with the layout instead of against it: one storage bay per bay line, walls free of awkward half-positions. Daylight placement changes how a floor is used far more than its cost suggests.

Depth here creates a hierarchy: 3 rows means front positions get used and rear positions get filled. Deciding which is which up front is what keeps 100x120 workable. Security and after-hours access are easier to design in the door layout than to bolt on later.

Extension is cheapest along the 120 ft dimension, where each added bay repeats work already framed; widening past 100 ft is a different frame rather than a longer one. Growing to 100 by 152 adds a 4th run of storage bays — useful if the constraint is storage bays rather than the 24 ft already spare at the far end.

Configured as an office front with a warehouse floor behind it, 100x120 is judged on whether the 12 storage bays it holds match the operation, and on whether the 12 feet of spare width leaves the route this mode depends on.

• Does the work need an interior street with independent zones on both sides and turning room at each end, or does it need a second lane that this 100-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?
• How deep is the public zone, and what is behind it?
• Will the shell be subdivided, and are services planned for that?

The alternative reading of the same footprint is a light commercial unit run by a small resident team: welfare space has to be carved out of a work area rather than found at the end of the run. Dividing the 12,000 sq ft by the 22 by 32 ft storage bay gives roughly 9 positions before circulation is deducted a second time for cross movement. Whether the plan keeps 9 or drops to 6 comes back to the question this footprint is really answering: what share of this footprint should be finished office, and where does the boundary between quiet and loud sit?

Treating the last 10 feet as a room is the recurring planning error at 100x120: there is no staging zone, so assembled orders occupy the loading area and block it during the busiest hour. 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 12-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.

Goods run front to back or side to side and people run front to middle. Where the two routes cross is the point to design, because it is where accidents, delays and noise complaints all concentrate. Staff welfare space is the first thing squeezed and the first thing that causes complaints. That movement pattern, not the 12,000-square-foot total, is what decides whether the leftover 10 feet is useful here.

Across a 100-foot span the 3:12 pitch adds 12.5 feet between eave and ridge. The centreline measures 26.5 feet; anything parked or stacked near a wall lives with the 14-foot eave. The span is the commitment; everything inside it is rearrangeable later, and the 100-foot dimension is not.

Height on a 100 ft span is a separate decision from the 120 ft length, and it is the span that sets the frame's behavior. Raising the eave over 12,000 sq ft affects every bay along the 120 ft dimension, so the test is whether office and warehouse split genuinely needs the extra clear height or only the floor area.

• 60x80 moves the count from 12 to 6 storage bays (3 across by 2 deep), which is the reason to choose between them.
• 40x120 moves the count from 12 to 6 storage bays (2 across by 3 deep), which is the reason to choose between them.
• 50x100 moves the count from 12 to 6 storage bays (2 across by 3 deep), which is the reason to choose between them.

Because this footprint is planned as an office front with a warehouse floor behind it, the useful next reads are different from the ones a differently shaped commercial building suggests: office and warehouse split, loading and staging planning, racking height planning.