Looking to replace the granite posts on our porch with metal columns. (see
pictures of porch http://mysite.verizon.net/stamkis/ )
Need to jack up and support the porch in order to remove the granite
footings and granite posts. The footings are about 10 or so inches in
height and stand on edge. They've shifted over the years and the granite
columns are in bad shape too. I would like to keep the granite base and
posts as a facade hiding the new metal(filled with concrete or lally)
columns.

Since the porch is so unstable I would like to support it in multiple
locations before I begin jacking it up. To be honest, I've never used a
house jack before and this particular porch setup is challenging.

A few people have given me ideas, but I'm not confident in using any of
them. Everyone seems to be in agreement that the front corner of the porch
needs to be handled first.

I'll go through some of the ideas below.
1. Place a big turn-style house jack two feet or so behind the corner
granite post.
Place a 4x4 pressure treated post vertically above the jack. (I assume
that is how they work.)
Run a 4x6 beam diagonally across two adjacent band joists. Jack up
very slowly as necessary supporting both bands with the one cross beam using
a vertical 4x4.
Then dig a hole for sauna tube directly behind the corner granite
posts. Fill with concrete. Let it harden. And, basically do the same
thing for the permanent structure. Run a short support beam diagonally
across the two band joist and put a lally column beneath it... resting on
the new concrete.

Personally, I would want to move the granite out and put the steel post
directly in the corner where the original granite post were. Almost seems
there should be two metal post there. I prefer not to use pressure treated
wood because in 15 years or better they will have to be replaced.

I don't know anything about construction practices but the first cross beam
idea seems a bit scary and running a cross beam to support the porch doesn't
appeal to me. I'm also a bit worried about digging and jacking without the
rest of the porch being better supported.

2. Idea # 2 Similar to the first except using a longer and stronger 8x8
beam to run across the diagonal. The beam would be supported on the two
outer sides of the porch using a platform at one end and a jack on the
other. Couldn't quite get the concept of what this person meant by
platform. Something solid for sure.

He also suggested similar scenarios for supporting the rest of the porch at
the same time.
Again, I was a bit puzzled about how this would work. What I like about his
idea is that there would be a lot of room to work. And, no digging would
take place near jacks.

3. Idea #3 Get a 2x12 rest it flat side under the bank. Angle it so the
bottom rest on some solid wood. Drive two 2x4's a couple feet into the
ground behind the wood to keep the 2x12 from slipping. Also, nail two
pieces of wood along the top side of the 2x12 at the bank joist to keep it
from slipping side to side.

Previous to this, the corner could be jacked up using the existing granite
base. Then, let it rest on the 2x12. Once the porch is supported then move
the granite base and columns and dig the sauna tubes. Then place posts. My
main concern is how do you keep the 2x12 board from slipping forward at the
band?

I like this idea. I'm just not over-confident in it. Don't worry, I will
have someone more knowledgeable help me doing this.

My main problem in jacking this porch up are as follows. I want to move the
granite base and still support the porch at the same time. If it were
simply a matter of jacking the house up vertically on the base, that would
be a piece of cake. However, I would like to move the base and dig in the
same area to put in the sauna tubes. Thus, I most likely need to be away
from the area when jacking it up. Any ideas on how to jack up this porch
are appreciated. A web site with diagrams might be even more helpful.

As you can probably tell I am not getting the best advice. One contractor
recommended I put up some 4x4's under a number of the joists. Then, run
2x8's perpendicular to the existing joists, supported by 4x4 posts. I put
in a few 4x4's and everyone started telling me all I was doing was holding
up part of the floor, not the porch. They said the same would happen when I
ran the 2x8's under the floor joists. So, I abandoned that plan because the
bands were not directly supported.