What you need to know about jack posts

You may often require the use of a steel post that would allow the temporary support of ceilings, walls and trenches, for the process that is commonly known as shoring. Shoring is the process which is used to temporarily support a building, vessel structure or a trench with shores or props during times when there is a danger of collapse or during repairs or alterations. The term shoring is derived from the idea of shore a timber or metal prop. It can be vertical, horizontal or even angled.

The type of steel post often used for the shoring process is called the jack post. They also have a number of other trade names affiliated with them, which include lally column and acrow prop. They are widely standardized. They have a structure that is telescopic tubular, and consist of two primary parts. Their ends are usually fitted with flat plates which tend to provide additional support area. Jack posts are usually split into two in the middle, with the upper end carrying the jack specifically designed to support the lower portion. Length can be adjusted by pulling a pin and sliding the two sections within each other till they almost fill the gap. Jack post is not used for scaffolding; rather, they are used for building repair or alteration work. One way it is typically used is for shoring purpose is as a temporary support while the original supports are being removed or repaired. If the masonry itself us to be supported, the brickwork first has holes knocked through it, and then a strong ‘needle’ or ‘strong boy’ is placed through the hole. It may also be used to directly support existing windows or doorways, or support them via needles. Since the end plates of the posts are usually small, there is little sideways support offered by them. Hence, in case sideways force exists, props should be strutted or laced with scaffolding poles.

Jack post or Acrow Props are now described commonly by a British Standard BS$) &$:1982. A similar lightweight European prop design exists. These have a maximum capacity of only 5 kilonewtons.