Well you posted while I was typing so I understand it better now!
It's confusing because you use the terms interchangeably. They are different . The flooring sits on the floor joists. the joists sit on the support beam. Beams run horizontal, columns and posts run vertical.
One of the joists
in my crawlspace rotted out - the previous owner stuck a jack under the beam
and left it for me to deal with. So I'm gonna deal with it, but am not sure how to approach the fitting. The joist
is a 2 1/4" x 10" rough cut doug fir beam
. If i wanted to fit a 4x6 support column to the beam
, I'd have to carve a channel in the 4x6 to fit the joist
- at least a 2" deep channel, preferably 4" channel so that I can run a bolt through the assembly to tie them together. I can't use standard structural ties because the joist
isn't a "standard" width - they didn't use 2x10's, they used rough cut 2x10's.
Generally speaking when a joist rots, you "sister" it on both sides with similar width boards.
When a beam rots, you build a temporary header to support the joists and replace the beam.
When a post rots out you build a temporary post away from the original, remove the rotten one and replace it. Or, if the temporary one works, fits and makes sense, leave that in place. A screw jack or hydraulic bottle jack will prove invaluable.
Your question is then...Do I leave the column jack in place or replace it with a post?
I'd build up a raised portion of concrete or use a solid block and then put my new Pressure Treated post on that. I'd dunk the whole end in a buck of used motor oil overnight as well, or spray it with automotive undercoating and let it dry.
I have done this numerous times, kinda fun in a way. When you hear creaking noises and the lever on the bottle jack gets hard to push you know you've got some weight on top. I have worked with a lot of steel beams and steel posts, but the temporary ones were made of 2"x 10" s in a box form and the jack sat on a stack of plywood on top. If you are not comfortable doing this, better to have an "expert help" or do the entire job. BTW I have 3 automotive jacks, 4 bottle jacks, including a 20 ton, several screw jacks, and a 5 ft HD Off Road truck jack. Hydraulics are GREAT!