50×120 Monitor-Style Ag Building — Washington County, OR

The project

The owner here runs a working agricultural operation, the kind that turns large equipment in and out all day and needs room to do it under cover. The goal was a lot of usable space on one footprint: a place to store and stage machinery, work on it out of the Oregon weather, and drive tall equipment straight in without ducking under a header. That meant high doors, high clear height, and a layout that kept everything connected. Miner Pole Buildings took that goal and built it on private acreage in Washington County.

The answer was a monitor-style building. A 50-by-120 ag-exempt main runs down the center at a 24-foot eave, raised above two 20-by-120 enclosed wings that run the full length along each side. A band of clerestory windows set into the raised center wall pulls daylight deep into the floor, and shared interior eaves open the main directly into each wing. The footprint comes to 10,800 square feet, and the open eaves between the main and the wings mean equipment can move through the whole structure without going back outside. The main carries four 20-by-14 overhead doors split across its two gable ends. MPB ran 96-inch high-lift track and chain-hoist operation on those doors so the openings clear the kind of tall equipment that doesn’t fit through a standard farm door, and so the door panels ride up out of the way instead of eating into the headroom underneath.

A 24-foot eave is tall for post-frame, and MPB built the structure to match. Laminated four-ply posts carry the wall loads at that height where a single solid post would be working too hard. On the roof, MPB specified scissor trusses on the main, which lift the interior ceiling line and keep the clearance under the trusses at roughly 22 feet, so the tall-door clearance carries all the way through the building rather than stopping at the opening. The whole structure is engineered for 25 psf snow load at 115 mph wind, the load case for this part of Washington County, with posts set about 60 inches deep on concrete pads and gravel-and-concrete backfill to hold that in wet valley ground.

The two wings handle the enclosed, finished side of the operation. Each one is closed to grade on three walls and opens to the main on the fourth, with its own pair of 12-by-12 overhead doors on the gable, vinyl windows for daylight, and walk-through man doors so people can get in and out without cycling a big door. MPB upgraded the roofs to half-inch plywood and felt across the whole building, which gives the operation a clean cavity to add insulation later without redoing the roof. The steel is 29-gauge Vantage Tuff-Rib with rat guard around the base to keep the closure tight where the metal meets the slab.

What the owner ended up with is one building doing several jobs: open drive-through bays for the big equipment, enclosed and lockable wings for the work that needs walls, and door clearances sized for the actual machinery instead of a catalog average. That combination of a tall main, real door height, and enclosed wings on a single connected footprint is exactly the kind of agricultural building MPB is set up to engineer and build.

Specifications

• Size: 50×120 main with two 20×120 enclosed side wings — 10,800 sq ft footprint
• Profile: Monitor style, a raised center over two lower full-length wings
• Eave height: 24’ at the main, 14’ at the outer wing walls
• Clearance under main trusses: roughly 22’
• Roof: 4/12 pitch with scissor trusses on the main for added interior height
• Engineered for: 25 psf snow load and 115 mph wind (Exposure B)
• Posts: laminated 4-ply columns, about 60” embedment on concrete pads with gravel-and-concrete backfill
• Cladding: 29-gauge Tuff-Rib steel roofing and siding with rat guard

Scope of work

• 50×120 ag-exempt main building with two attached 20×120 enclosed eave wings, a raised-center monitor profile sharing interior eaves
• Main closed to grade on both gable walls and open into the wings along the long eave walls; each wing closed to grade on three walls
• Four 20×14 chain-hoist overhead doors split across the main gable ends on 96” high-lift track
• Four 12×12 overhead doors on the wing gables, plus walk-through man doors for everyday access
• Operable vinyl windows across the wing walls and a clerestory window band in the raised center for natural daylight
• Half-inch plywood and felt across all roofs, leaving a clean cavity to add insulation later

Doors and windows

Type	Qty	Size	Notes
Overhead doors (main gables)	4	20’×14’	Commercial sectional, 96” high-lift track, chain-hoist, white
Overhead doors (wing gables)	4	12’×12’	Commercial sectional, low-headroom track, white
Man doors	10	3068	Steel-sided with lockset
Windows	—	5020	Operable white vinyl across the wing walls