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Metal Building Lingo- If I can learn it, so can you!

Updated: Dec 24, 2020

A-Z, the buzz words you should get familiar with.

Diagram courtesy of Gonzales Construction

Approval Drawing:

A product drawing sent to the customer to verify design and dimensions and to

verify the sales contract description of materials and services the manufacturer

has agreed to furnish.


A structural member which is ordinarily subject to bending and is usually a horizontal member carrying vertical loads.

Clear Span:

A clear span building has no internal supports. The entire space under the roof is usable.


A tapered pin used to align holes in steel members to be connected. Also called "Spud Wrench".


The on-site assembly of pre-engineered components to form complete structure.

Fixed base:

A vertical structural member, bolted to and positioned at 90 degree to a sidewall column to provide additional base fastening and to prevent column rotation.


(1) In metal products, a number designating a specific thickness of metal sheet, or diameter of wire, cable or fastener shank tabulated in a standardized series, each of which represents a decimal fraction of an inch (or millimeter).

(2) Distance in inches (or millimeters) between adjacent lines of holes or fasteners.

High Tensile Steel:

Structural steel having a yield stress in excess of 36,000 pounds per square inch.


Insulation is any material used in building construction to reduce heat transfer. The most common steel building insulation used is vinyl backed fiberglass. Insulation is available in different thicknesses depending on the application and the R-value required.


Joists are supporting open web beams used in the roof or the floor of a mezzanine. Joists are a cost effective solution for supporting large loads or spanning large distances.

Knee (or Haunch):

Also known as Haunch. The deepened portion of a column or rafter, designed to accommodate the high stress where column and rafter intersect and connect. The rigid frame column and rafter come together to form the knee. The knee will be the lowest point in the roof of a building.


A lean-to structure has only one slope or pitch, similar to a single slope, but is supported by a column on one side and another structure on the other. Lean-To buildings can be attached to standard steel building or any solid structure with the ability to carry the additional load.


More than one building tied together; multiple gable buildings.

Electric/Air Nibbler:

An electric hand tool used to cut steel roof or wall sheet openings.


A wavy appearance in a metal panel that is aggravated by expansion of the metal.


A secondary, cold formed horizontal structural member located in the roof to support sheeting, that is itself supported by the primary structure framing.

Roof Slope or Pitch:

Slope of a roof plane expressed as a ratio of vertical rise per unit of horizontal run.

Structural Steel Members:

Load carrying members, may be hot rolled sections, cold formed shapes, or builtup shapes.

Turn of Nut Method:

Turn of the nut method is a tightening specification for structural bolts in a connection. A rotation of the nut from one position to a final snug position will produce at least the desired minimum tension on the bolt. ("Snug" is defined as the point at which the material between the bolt head and nut is rigid. If power tolls are used, "snug" would typically be the point at which the wrench began to impact.)


Wind load on a building which causes a load in the upward direction.

Vapor Barrier:

Material used to retard the flow of vapor (moisture) into walls and thus prevent condensation within them. Can be used on the inside of the wall assembly (Cold climate) or the outside (Hot/humid climate)

Wall Covering:

The exterior wall skin consisting of panels or sheets and their attachments, trim fascia and weather sealants.


Used in buildings to provide additional bracing and strength. This can be done with steel cables, rods or even angle in severe cases.

Yield Stress:

The stress at which the strain ceases to be directly proportional to the stress. The stress by which steel is identified such as A-36 indicated 36,000 psi yield.

"Z" Section:

A member of cold-formed from steel sheet in the shape of a block "Z".

There ya go, Friend! A little something to help you sound like you know what's going on when you start calling salesmen.

These words and their definitions were taken from a PDF document created by Federal Steel Systems. The the original PDF can be found here:

Download PDF • 274KB

This PDF is 16 pages of building terms specific to metal buildings. Knowing some of these terms may be helpful for you while shopping for your building. You may think, "well its not that important to know all of this stuff, I'm not building it myself." but keep in mind, it's a lot easier to sell someone junk when they have no clue its junk.

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Alex Ramirez
Alex Ramirez
Jun 13, 2021

Thank you! Definitely helps out in the learning process.


Megan Woodworth
Megan Woodworth
Aug 21, 2020

You’re so welcome, Allen!



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