How Basement Supports Impact Floors Above: Adjustable Steel Columns

If you have a basement, or a crawl space, you probably have adjustable steel columns, also known as screw jacks and beam jacks.  These are hollow steel posts designed to provide structural support. An attached threaded adjustment mechanism is used to adjust the height of the post.  Adjustments can properly distribute support to the floors above, to prevent out of level conditions that might cause structural damage.  A professional home inspector can determine if these appear to be properly positioned and adjusted, or may suggest consulting a Structural Engineer.

​A few facts about adjustable steel columns:

• They are usually found in the basement.  In some places, these are called lally columns, but this term can also apply to columns that are concrete-filled and non-adjustable.
• Adjustable steel columns can be multi-part assemblies, sometimes called telescopic steel columns, or they can also be single-piece columns.

Defects that are often found in adjustable steel columns:

• The 2012 International Residential Code (IRC), Section R407.3, columns (including adjustable steel columns) says... Adjustable steel columns "shall not be less than 3-inch diameter standard pipe." 

It is possible that a 2½-inch post may be able to support the load above it. However, supports smaller than 3 inches in diameter would violate the IRC even if not necessarily defective. In some cases, a 4-inch diameter post could buckle if the load exceeds the structural capacity of the post - even if not defective.  Structural engineers -- not inspectors -- are the authority on whether adjustable steel posts are of adequate size. But a professional home inspector can render an opinion as to when to consult a  Structural Engineer.

Other Possible Defects In Structural Supports:

• Non Compliant Paint Allowing Rust To Form:  According to the IRC Section R407.2, All adjustable steel columns should be protected by rust-inhibitive paint.  It says, specifically, "All surfaces (inside and outside) of steel columns shall be given a shop coat of rust-inhibitive paint, except for corrosion-resistant steel and steel treated with coatings to provide corrosion resistance."   Inspectors will not be able to identify paint as rust-inhibitive, but may be able to observe the earliest stage of rust beginning to form and recommend further attention.  In dry climates where rust is not as much of a problem, rust-inhibitive paint may not be necessary. Visible signs of rust constitute a potential defect. Advanced rust will weaken the post and could cause structural collapse and extensive damage.
• The post is not straight. The post should not bend anywhere along it's length or especially at its mid-point. Bent Posts indicate that the column cannot bear the weight of the house.  The maximum load is affected by many factors, such as the height and diameter of the post. 
• The column is not connected to the floor. An inspector can determine whether a connection between the post and the floor exists as long as this connection has not been visually obscured.
• The column is not connected to the beam. To provide proper support, the post should connect to the beam above.  This connection provides additional resistance against lateral displacement.
• Too much extension:  If more than 3 inches of the screw thread are exposed the post may be overextended and thus have it's load bearing capacity reduced.
• There are cracks in upstairs walls. If a post is not properly adjusted, then cracks may appear in walls.  This would suggest a failure of the columns.