Light gauge metal telescoping jack posts are often used as a quick, economical way to reinforce a structural member that needs additional support. There have been some mixed messages on when you can use them and when you should not. Telescoping jack posts are capable of carrying a 4000 to 6000 lb. allowable load depending on the extension length and manufacturer, which is a pretty good capacity for most retrofit and reinforcement situations. Most jack posts we see in the field are installed upside down. The screw thread should be on the bottom. There is also nothing that really holds the post assembly together with other than the initial force created when tightening the post against the framing. For that reason, we have seen many jack post failures when they lose their initial tightening force.
Here are our suggestions of when you can use light gauge telescoping jack posts in lieu of masonry piers.
- When adding additional reinforcement to a floor system to take “bounce out of a floor” when the floor already meets Code without the posts.
- When jacking against an existing masonry foundation wall such as a basement half wall.
- When using for temporary shoring during renovations.
Light gauge jack posts that are commonly found at many hardware stores are typically not the kind that should be used for permanent support. For those, we recommend a structural steel telescoping post such as SmartJacks or Ellis Manufacturing Light Duty shoring column.