80x120 Agricultural Steel Building

This page is ordered around height and clearance, because at 80x120 the 22-foot eave limits a agricultural building sooner than the plan does.

The footprint holds 16 stacking bays — 4 across by 4 deep — and the remaining 2 feet is marginal: the leftover is absorbed by the loader's turning circle at the stack face.

What distinguishes 80x120 is depth behaviour: 4 rows along 120 feet after 14 feet of circulation, with 2 feet unaccounted for at the end of the run. Judge the plan by what has to happen on the worst day of the year, not on an average one.

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 4 runs of stacking bays at 26 ft, leaving 16 ft over — the 16 ft is where the argument about this size actually happens. Taken purely as arithmetic, 80 by 120 gives 3 stacking bays across the 80 ft dimension once 14 ft is reserved for movement, and 4 deep along the 120 ft dimension. Run as a hay, feed and forage storage, 12 ft across is below the 14 ft this use needs to be worth planning, so the leftover is absorbed by the loader's turning circle at the stack face Feed, fuel and chemicals want separation from where people and machines work, and separation is easier to plan than to retrofit.

This footprint is planned as hay, feed and forage storage. Spent as a square 98 by 98 instead, the same 9,600 sq ft would stand 4 stacking bays across rather than 3, 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 4 stacking bays 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 building fills once and empties over months. That asymmetry is what distinguishes forage storage from every other farm use: the layout has to work in reverse, as the stack recedes and the working face moves. Neighboring structures already set the yard's traffic pattern, and a new building either respects that pattern or reroutes the whole yard.

Read this page as a use page, not a construction page. Agricultural building is a use category on this platform, not a construction method: it covers farm buildings by what they hold and how the operation runs, and the same use can be built as a clear-span steel frame, a post-frame building or another system. The question it answers is how useful a 80x120 footprint is for this use.

The stored configuration carries a 22-foot eave and computes to 35.3 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. Whoever operates the building daily should read the plan before it is frozen, because they know where the pinch points are.

Stack height drives the eave, and the eave has to clear a raised grapple over the top of the finished stack. This is the farm use where height is usually the binding dimension rather than footprint.

Ventilation across 9,600 square feet at this height: farm storage brings moisture in with it: green hay, wet machinery and any animals all release it, so ridge-to-eave airflow is a planning priority and a tightly sealed building is usually the wrong instinct here.

The second use this farm footprint tends to absorb is implement and towed-equipment storage: the leftover only allows a tongue to project past the last implement rather than a working space. Dividing the 9,600 sq ft by the 18 by 26 ft stacking bay gives roughly 12 positions before circulation is deducted a second time for cross movement. Whether the plan keeps 12 or drops to 8 comes back to the question this footprint is really answering: how much forage can be stacked under cover, and can the loader still reach the back of the stack in February?

Treating the last 2 feet as a room is the recurring planning error at 80x120: the leftover is absorbed by the loader's turning circle at the stack face. Rows that cannot be entered independently end up used as one long space.

The 8 feet of spare width runs the whole 120-foot length — 960 square feet of wall strip. It earns its keep as shelving, staging or a walking route, not as another stacking bay. Circulation width is the first thing surrendered under pressure and the first thing missed afterwards.

Spent as a square 98 by 98 instead, the same 9,600 sq ft would stand 4 stacking bays across rather than 3, 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 4 stacking bays 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 building fills once and empties over months. That asymmetry is what distinguishes forage storage from every other farm use: the layout has to work in reverse, as the stack recedes and the working face moves. Neighboring structures already set the yard's traffic pattern, and a new building either respects that pattern or reroutes the whole yard. That movement pattern, not the 9,600-square-foot total, is what decides whether the leftover 2 feet is useful here.

The 80-foot gable can carry 4 openings, one per stacking bay, with 8 feet of wall left for piers between and beside them — the arrangement that keeps each position independently reachable. Daylight placement changes how a floor is used far more than its cost suggests.

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 hay barn planning or forage storage height should be the first thing reached from the door.

Loading is done by machine from the apron, so the surface outside the door does as much work as the floor inside.

At 24-foot nominal bays the structure works with the layout instead of against it: one stacking bay per bay line, walls free of awkward half-positions. Two feet of spare width reads as nothing on a plan and as a great deal when a machine is being turned.

Depth here creates a hierarchy: 4 rows means front positions get used and rear positions get filled. Deciding which is which up front is what keeps 80x120 workable. The plan is only as good as the route into it, which is a site question rather than a building one.

Forage demand grows in whole seasons, so extra capacity is usually taken by extending the stack run lengthwise or adding an open bay rather than by conditioning existing space.

Configured as hay, feed and forage storage, 80x120 is judged on whether the 16 stacking bays it holds match the operation, and on whether the 8 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 is the widest implement that has to come in fully assembled, and does it ever come in with an operator in a hurry?
• Does the building need a drive-through route, or is single-end access acceptable?

• 50x80 moves the count from 16 to 9 stacking bays (3 across by 3 deep), which is the reason to choose between them.
• 40x100 moves the count from 16 to 4 stacking bays (2 across by 2 deep), which is the reason to choose between them.
• 60x80 moves the count from 16 to 4 stacking bays (2 across by 2 deep), which is the reason to choose between them.

Because this footprint is planned as hay, feed and forage storage, the useful next reads are different from the ones a differently shaped agricultural building suggests: hay barn planning, forage storage height, feed storage buildings.

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. Security and after-hours access are easier to design in the door layout than to bolt on later.

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 hay, feed and forage storage is the fit-out hay barn planning implies, along with framed openings and the height chosen for the 80 ft span.

• the clear width the widest fully assembled implement needs
• whether the floor is left as dirt or gravel, partly concreted for the working end, or fully slabbed
• how many bays stay open for machinery and how many are enclosed for inputs
• the apron and yard surface machinery turns on
• interior partitioning between feed, tool and machinery zones