Steel columns and other framing components make up the structural skeleton of homes and businesses. These columns support walls and ceilings, and give the building its basic shape. Engineers and builders must choose from different types of steel columns based on budget, durability and aesthetic appeal. In many applications, the column design also reflects local building code requirements aimed at creating safe and stable structures.
Solid Angles and Channels
Solid angles and channels consist of single lengths of steel used as both vertical columns and horizontal beams to frame a building. They are not adjustable, and must be ordered based on size and length. Solid steel columns include I-beams, U-shaped channels and simple angle brackets. These components can be used individually to form a column, or combined for added support. They must be joined together at intersections or corners using metal bolts or welding techniques. Some installers add steel angle plates to increase the security of the connection between columns and beams.
While solid steel columns are frequently found in commercial structures, they are used less frequently in residential homes. Some builders choose steel rather than wood framing because of its added strength and durability, as well as its resistance to rot, termites and other pests.
Builders must typically spray steel columns with fireproofing materials to help prevent structural failure during a fire. This cementitious spray has a significant impact on the appearance of the column, making it difficult to leave columns exposed, and limiting the design potential of the space. To eliminate the need for spray fireproofing, builders may swap solid steel beams and angles for hollow steel tubes. These tubes can be filled with concrete to add fire protection, leaving the outside of the column free for paint or other finishes. The concrete may be reinforced with rebar or wire mesh to add additional strength to the column, or in accordance with local code requirements. These square or round cement-filled columns are known as lollys or lolly columns in some regions.
Adjustable columns consist of a hollow steel tube with a steel plate attached to either end. The installer can adjust the height of the column on site during installation to fit different applications. Some adjustable columns may feature multiple tubes surrounding one another in a telescoping design. These telescoping columns, or jackposts may not be used in permanent applications according to the American Society of Home Inspectors. Only adjustable columns with a single tube can be used in permanent applications. Telescoping models are designed for temporary repairs and renovations, and do not meet the majority of building safety codes.