100x120 Steel Gymnasium Building

Quantities, not prices, are publishable here: roof cladding runs 12,369 square feet — 3% above the 12,000-square-foot floor at a 3:12 pitch — with 148.1 cubic yards of nominal slab beneath it. Fire separation, egress and occupancy are determined for the specific building and can reshape this plan entirely.

Dividing equipment, its structural support and the controls for it are the cost distinguishing this from an open floor, and they are frame-dependent rather than a later addition.

• clear height above the playing surface
• the clear span across the court and its run-off
• the support wing with changing rooms
• impact-resistant lighting and interior surfaces

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

The footprint holds 6 divided bays — 3 across by 2 deep — and leaves 24 feet of depth for a cross-aisle at one end so a group can reach its own bay without crossing another one in use.

Commitment first: 60% of the 12,000 square feet goes to divided bays at 1200 square feet each, and 3,600 square feet survives as edge strip. A footprint is worth its own decision when that split lands where the work does. Noise from this floor reaches the office, the neighbours and the yard, and separation is a plan decision.

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 divided bays at 40 ft, leaving 0 ft over — the 0 ft is where the argument about this size actually happens. Once a floor is divided, the subject stops being area and becomes separation. Netting, curtains, marked buffers and access routes decide whether three groups can genuinely work at once or whether each is distracted by the others. Egress and occupancy for a room holding a gathering are determined by the local authority for that building.

At 100x120 the operating question is a specific one: how are two or three simultaneous activities separated without any of them losing usable width? That is a different question from the one a steel gymnasium of another shape has to answer, and it is why this footprint is planned as a divisible floor carrying more than one activity at once rather than as generic covered area.

One opening per position works on this gable: 3 across 100 feet, with 10 feet of wall to distribute as piers. Splitting that margin evenly is what keeps the elevation buildable. Snow, wind and site exposure change what this shape costs to build long before the interior plan does.

Each bay wants reachable entry from the shared route, and one wide opening still handles equipment for all of them. Where every bay has its own external door, the perimeter loses the wall the activity needed.

The columns win at this footprint: 24-foot nominal bays against a 30-foot module means every layout decision starts from where the frames fall. Access, not area, is what makes a plan feel small once it is in use.

Depth here creates a hierarchy: 2 rows means front positions get used and rear positions get filled. Deciding which is which up front is what keeps 100x120 workable. Set the openings before the interior, because the openings cannot move and the interior can.

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 160 adds a 4th run of divided bays — useful if the constraint is divided bays rather than the 0 ft already spare at the far end.

Configured as a divisible floor carrying more than one activity at once, 100x120 is judged on whether the 6 divided bays 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 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?
• What clear height does the activity need, measured to the lowest obstruction?
• Are the run-off margins protected from storage and seating?

The activity pattern this floor could equally be planned around is an activity floor with a permanent spectator side: there is no concourse behind the seating, so spectators queue and stand at the floor edge. Dividing the 12,000 sq ft by the 30 by 40 ft divided bay gives roughly 6 positions before circulation is deducted a second time for cross movement. Whether the plan keeps 6 or drops to 3 comes back to the question this footprint is really answering: how are two or three simultaneous activities separated without any of them losing usable width?

Because 24 feet clears the 12 feet this platform treats as usable, the end of the run is a room rather than a gap: 2,400 square feet for a cross-aisle at one end so a group can reach its own bay without crossing another one in use. Temperature swing on a steel shell drives condensation decisions that outrank most layout preferences.

The 10 feet of spare width runs the whole 120-foot length — 1,200 square feet of wall strip. It earns its keep as shelving, staging or a walking route, not as another divided bay. The count of working positions, not the headline area, is the figure that survives contact with the operation.

Several timetables run in parallel and change over at different times, so movement into and out of the building is continuous rather than concentrated. Access to each bay from a shared edge is the whole design question. Acoustics in a hard-surfaced hall affect whether instruction can be heard, which is a usability question rather than a comfort one. That movement pattern, not the 12,000-square-foot total, is what decides whether the leftover 24 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. Where the building sits on the site changes how much of this floor is genuinely reachable.

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 divisible sports floor planning genuinely needs the extra clear height or only the floor area.

Ventilation across 12,000 square feet at this height: an intensively occupied volume with high activity levels, where air handling is planned for the occupied peak.

• 60x80 moves the count from 6 to 4 divided bays (2 across by 2 deep), which is the reason to choose between them.
• 40x120 moves the count from 6 to 3 divided bays (1 across by 3 deep), which is the reason to choose between them.
• 50x100 moves the count from 6 to 2 divided bays (1 across by 2 deep), which is the reason to choose between them.

Because this footprint is planned as a divisible floor carrying more than one activity at once, the useful next reads are different from the ones a differently shaped steel gymnasium suggests: divisible sports floor planning, activity bay separation, shared access routes.