80x100 Steel Church Building

No price appears on this page. The quantities that scale an estimate at 80x100 are 8,000 square feet of slab, 148.1 cubic yards of nominal concrete, 7,200 square feet of wall cladding and 8,433 square feet of roof cladding. Every foot of width added multiplies through the roof and the frame; every foot of length mostly adds skin.

Proportion drives cost here as much as size does: 360 ft of wall around 8,000 sq ft is 0.045 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 a gathering room with a classroom and support wing is the fit-out classroom wing planning implies, along with framed openings and the height chosen for the 80 ft span.

• the clear span across the assembly room
• the support wing and its internal partitions
• acoustic and interior finish work
• egress doors distributed around the assembly volume

This page is ordered around height and clearance, because at 80x100 the 20-foot eave limits a steel church building sooner than the plan does.

The footprint holds 9 classroom modules — 3 across by 3 deep — and the remaining 8 feet is marginal: the leftover leaves the corridor at plain width, so release and pickup happen at the room doors themselves.

Read this footprint through its span. 80 feet across is the fixed constraint; 100 feet of length is the negotiable one, and at 1.25 to 1 the building is close to square, so movement runs in both directions. Utilities entering on the wrong elevation quietly rewrite the interior layout.

A 80 by 100 footprint is a mildly directional plan: 8,000 sq ft enclosed by 360 ft of wall, at a 1.3:1 length-to-width proportion. Along its 100 ft dimension it takes 3 runs of classroom modules at 26 ft, leaving 22 ft over — the 22 ft is where the argument about this size actually happens. Once teaching spaces enter the plan the building stops being one room with edges and becomes a room plus a corridor. The corridor is the real subject: it decides whether small rooms are usable while the large room is occupied, and it is the element most often left as leftover space instead of being planned. Technical infrastructure — sound, projection, lighting — needs positions and routes reserved before the interior is finished.

This footprint is planned as a gathering room with a classroom and support wing. Two flows overlap here — adults arriving for the main room and children being taken to and collected from small rooms — and they peak within minutes of each other. Separating those two flows at the entry is the layout decision that matters most. Sound behavior in a steel shell is a treatment decision made after the frame is fixed, which is why it is worth raising before it is.

The stored configuration carries a 20-foot eave and computes to 33.3 feet at the ridge on a 4:12 pitch — a 13.3-foot rise across 80 feet. Height is therefore not uniform, and the sidewall is the constraint. A wider bay is a structural decision and a longer bay is a layout decision; the two are often confused.

Height on a 80 ft span is a separate decision from the 100 ft length, and it is the span that sets the frame's behavior. Raising the eave over 8,000 sq ft affects every bay along the 100 ft dimension, so the test is whether classroom wing planning genuinely needs the extra clear height or only the floor area.

Ventilation across 8,000 square feet at this height: a room that fills and empties fast needs air handling matched to that pattern rather than to its floor area.

The secondary demand this footprint has to absorb is a chapel-scale gathering room with essential support rooms: there is no vestibule depth, so arrival and departure happen inside the room itself and the back rows absorb it. Dividing the 8,000 sq ft by the 22 by 26 ft classroom module 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: how should the footprint be divided between one large room and a set of small rooms that must be reachable without crossing it?

The 8-foot leftover depth falls under the 12 feet this platform treats as usable for a steel church building, so the leftover leaves the corridor at plain width, so release and pickup happen at the room doors themselves. Insulating later is possible; framing for insulation later is much harder.

The 14 feet of spare width runs the whole 100-foot length — 1,400 square feet of wall strip. It earns its keep as shelving, staging or a walking route, not as another classroom module. Long spans buy flexibility that is only worth paying for if the operation actually changes shape.

Two flows overlap here — adults arriving for the main room and children being taken to and collected from small rooms — and they peak within minutes of each other. Separating those two flows at the entry is the layout decision that matters most. Sound behavior in a steel shell is a treatment decision made after the frame is fixed, which is why it is worth raising before it is. That movement pattern, not the 8,000-square-foot total, is what decides whether the leftover 8 feet is useful here.

The 80-foot gable can carry 3 openings, one per classroom module, with 14 feet of wall left for piers between and beside them — the arrangement that keeps each position independently reachable. Service routes are cheap to plan now and expensive to retrofit through a finished shell.

Interior door positions outrank exterior ones in this mode. Sightlines from the corridor into each small room, and a second exterior exit at the far end of the wing, are what make the arrangement workable rather than merely legal.

At 25-foot nominal bays the structure works with the layout instead of against it: one classroom module per bay line, walls free of awkward half-positions. Depth is bought cheaply and width expensively, which is why this proportion tends to be argued about before anything else.

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 80x100 workable. Height is the dimension people regret; it cannot be added later without rebuilding the frame line.

Support wings extend end-on. Adding rooms mid-wing means cutting the corridor, so the corridor should be drawn to a length that can be continued rather than to the length currently needed.

Configured as a gathering room with a classroom and support wing, 80x100 is judged on whether the 9 classroom modules it holds match the operation, and on whether the 14 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 100-foot length being bought for depth, or for the repeated bays — eight to ten repeated bays, which makes the layout a scheduling problem as much as a spatial one?
• What span does the assembly room need for the seating layout you intend?
• Is the support wing on the side or the end, and how does the lobby connect them?

• 40x80 moves the count from 9 to 4 classroom modules (2 across by 2 deep), which is the reason to choose between them.
• 60x60 moves the count from 9 to 8 classroom modules (4 across by 2 deep), which is the reason to choose between them.
• 50x80 moves the count from 9 to 4 classroom modules (2 across by 2 deep), which is the reason to choose between them.

Because this footprint is planned as a gathering room with a classroom and support wing, the useful next reads are different from the ones a differently shaped steel church building suggests: classroom wing planning, corridor and circulation planning, multi-room assembly buildings.