Lally columns, jack posts and floor jacks are a type of weight bearing support column that is permanent or temporary. They tend to be round, steel-walled structural column that is used to support weight-bearing beams which carry significant weight/load.
Lally column can be also referred to as a lally, steel column, lolly, lollie column, fixed length column or structural columns & piers. It refers to a non-adjustable, concrete filled support column whichhas a monolithic design which makes it stronger than the other two. While it can be used for both permanent and temporary structural projects, its fixed size makes it preferable for permanent structural projects rather than temporary structural projects.
If a lally column is used as a permanent support, it has to necessarily satisfy requirements such as tubing thickness and filling it with concrete. So, it is advisable to check with your local building inspector.
A mono post is can also be referred to as an adjustable building support column, steel column, structural columns & piers, teleposts or red-I-Posts. They are designed to be permanent building columns. They tend to be fully assembled, self-contained unit and are normally adjustable in lengths up to 12 feet.
According to ICC-ES reg, it is compulsory for the adjustment nut as well as the screw to be placed at the footer. It is also required for a beam plate or saddle plate to be placed t the top to secure the column to a support frame. An adjustable base set or end plat is needed at the bottom. This is in order to remove lateral movement.
Jack post tends to be designed to be temporary support columns and need to be assembled. They are generally fully adjustable. They also have double carriage nut and bolt for added strength and safety. Jack posts are generally adjustable in lengths not greater than 12 feet. They are also the weakest out of all support column types as they lose a percentage of load rating due to localized loading.
In order to reduce the chance of crushing the lumber or breaking through the concrete floor, a minimum of 1/2″ steel plate (3/4″ or 1″ is better) is required to be placed the under the ceiling joist (on top of the post) as well as on top of a 6×6 or 8×8 post (on the bottom of the post or bottle jacks).