Adjustable steel columns are hollow steel support members that support beams and joists in buildings. They are generally found in basements and crawlspaces. They are sometimes called jack posts or screw jacks due to their threaded adjustment. This threaded adjustment allows them to be used at varying heights.
A few facts regarding steel columns:
- Adjustable steel columns are sometimes referred to as lally columns although this term sometimes is used to describe non adjustable columns.
- They can be manufactured as two part assemblies which are sometimes called telescoping columns.
Some common defects with steel columns:
- Columns less than 3 inches in diameter – Many residential codes require that steel support columns be a minimum of 3 inches in diameter to adequate support the required loads. Often times a 2 1/2 in post may be adequate but that is for a structural engineer to decide.
- The post is not coated with paint. All steel columns must be coated with rust inhibitive paint – All surfaces inside and outside must be coated to protect the columns from deterioration.
- The post is not straight. As a general rule steel columns should be installed plumb, a 1 inch displacement from top to bottom is the max. Any bending within the post is also an indication of failure.
- The column is not mechanically connected to the floor.
- The column is not connected to the beam. Both ends of steel columns must be secured to protect the connections from lateral displacement.
- More than 3 inches of threads exposed at the adjustment screws. If the adjustment screw is turned out too far the adjustment end can become unstable.
The inspection of the basement support system is an integral part of a home inspection. I often find deficiencies with support columns. Any bending or displacement with the columns can indicate larger issues, although a structural engineer may be necessary to confirm serious issues.
As always, I hope you took some value from this post and if you have any home related questions, please let me know at the email address below.
-AZ
Aaron M. Zuehlke is the owner and a Certified Master Inspector® at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing, Mold Testing/inspection, Well Inspections/Well Water Testing, Residential Thermal Imaging, and Manufactured Home Foundation Certifications. He also manages several rental properties through Zuehlke Properties, LLC. He can be reached by email at Aaron@Zuehlkeinspections.com or by calling the office at 608-931-7485.