Screw Jacks or?

[wfopete]

I'm going to need to support a floor temporary with something until I get the final post in place. I figured I wanted to do it with some type of screw jack. The distance will be about 9 feet from the floor to the beam.

Any suggestions on sources for these or a better solution?

 

[rieferman]

Screw/post jacks are very useful to have around and will do the trick inexpensively. Available at home depot (or similar) for around $50 or less for the size you'd want.

Be careful to use a stable and strong base for them to set on since in many situations you need to build up to get to the desired height.

That said.. for a temporary support, I'll often just use some spare building material (like 2x6's) cut a 1/2" longer than needed.. kick in the bottom side to provide upward lift.

my barn thread (see signature) on the early pages shows some application shots of post jacks.

 

[blkhonda1991]

Be careful to use a stable and strong base for them to set on since in many situations you need to build up to get to the desired height.

That

this is the most important part...you are putting a point load somewhere that was not designed for one too so you should spread the load out by putting down some cribbing to spread it a bit

 

[rieferman]

I keep scrap 4x6 and 6x6 lengths for this purpose. When layed on their side, they're very stable, and the pressure won't split it. I would NOT recommend using 2xAnything material layed flat as it will split under pressure.

Do NOT use a cinder block with the flat surface up, it is not designed for load. Do NOT use bricks, they crush too.

You don't want to use a post jack at an angle as it can slip out. Use a level once you have it roughly in position, don't eyeball it. For 2 seconds spent checking, it makes it safer.

 

[wfopete]

I have a slab floor 6-8" thick. If I go with straight lumber I'll use a 4x4 and a concrete "deck block" as a base. I think that will provide a stable base and help spread the load, yes?

 

[diogenes]

For bases on my temporary jack posts I use these railroad rail plates. The prior owner of my house picked some up somewhere and they work fine.

The above link is for clarification only, I have no idea if they are a good source of them. The minimum order is only 10K pieces, BTW.

 

[rieferman]

from the sounds of what you're doing, a piece of 4x4 on a concrete floor will be plenty sturdy in my opinion.

edit: Btw, don't use a bottle jack for this type of operation. It's tempting to do so, and they're quite good at the initial picking up of a structure. BUT, the seals can go (and often do so at the worst time), so bottle jacks are best for picking something up where you plan to support it with a solid post once it's up. (I think this the same advice car guys would give you about using bottle jacks to pickup a car... pick it up, put jack stands in.. in a building situation, pick it up, put a post in)