Metal & Steel Building Anatomy

Metal Buildings 101: The Metal Building Anatomy

It helps to know the basic terminology for steel and metal buildings so that you can convey your needs clearly and effectively to your Arco sales representative.

Arco steel or metal buildings have three basic dimensions: width, length, and eave height. The width is the distance from the outside of the sidewall girt on one side to the outside of the sidewall girt on the opposite side. The length is the distance from the outside of the endwall girt on one endwall to the outside of the endwall girt on the other endwall. Eave height is the distance from the bottom of the base plate to the top of the eave strut.

Most metal buildings have four outside walls. Two of these walls are called sidewalls. This is the wall where the roof meets the wall and the contact point aligns parallel with the finished floor. This wall also determines the length of the building. The other two walls, called endwalls, show a rising line where the walls meet the roof and the height of the wall changes. On a gabled building this is the wall where the peak of the roof is obvious. On a single-slope building or lean-to the endwall shows the wall sloping from a high to low side. The endwall determines the building width.



The point where the sidewalls meet the roof is called the eave. Eave trim finishes the raw edges of the panels, or one might choose to add a gutter system to catch the rain flow from the roof. Eave height is determined by measuring the distance from the bottom of the base plate to the point where the roof and sidewall intersect. It is important to keep in mind that eave height and clear height inside the building are not the same. If you have a need for specific clearance inside your building, please speak to your sales representative so that they can help you to determine the necessary eave height that you will need.
The roof pitch or roof slope is usually shown as a ratio to 12 (i.e., ½:12, 1:12, 4:12, etc.). When inches are used as a basic unit, a 2:12 roof pitch means that the roof rises 2 inches in every 12 inches measured horizontally across the width of the building from the sidewall to the peak of the building. The point where the two rising halves of the roof meet at the endwall is called the peak. If you travel along the peak of the roof from endwall to opposite endwall, this is known as the ridgeline.


EXAMPLE: If the above building is 40' wide and has a 12' eave height, the height at the peak of the roof would be 18'8" with a 4:12 pitch.

20' (to centerline) x [4"/12"] = 6'8" (of rise) + 12' eave height = 18'8"

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