"Alan McKay" wrote in message
.. .
Folks,

I've got a bit of a saggy floor in my 130 year old home, and want to
jack it a bit. I've already had a structural engineer look at it and he
told me what has to be done, but not how to do it.

I've got to put 12 feet of 6" I-beam in, with 3 posts. OK, easy.
I need a good hydralic jack. Ok, easy.

1) You only use a hydralic jack if you want to lift a heavy load relatively
quickly and then put something under the load and remove the jack. If the
circumstances are as I describe them (e.g.: wood wedges or packing can be
emplaced to hold the load after the jack is removed) then hydralic jacks are
fine. They are easy to use and with a little calculaton you can determine
how much lifting force you are employing.

2) Most folks use the steel poles purchased at a "home store" like Home
Depot. At one time "they" made them so that one pole could roughly adjust
from about 4' to 8' with in 4" steps and the screw adjustment at the top
would give you another 6". Now they just sell the solid poles with a 6"
screw but they are stocked in various lengths. That means that if you have
a total lift more than a few inches, you may have to buy a shorter pole and
when it runs out of capacity, bring in a longer pole. But they are
relatively inexpensive and can be sold at yard sales for a good priice when
you no longer need the shorter ones (the longer ones will likely stay in
place.) Obviously, you determine the length range needed before you buy.

You may want to secure both the top and bottom of the jack to the beam you
are lifting and and floor respectively. A poured concrete floor may "punch
through" At the minimum, you should drill a hold through any concrete to
see how sound it is. When in doubt, make a hole in the floor and pour a
fresh footing. If you are using bedrock for a "support" then it's even
more important to ensure that the bottom of the jack doesn't move under the
load. Also, just because you have some rock in your basement doesn't mean
that its "bedrock." It could be that the guy whol built the house didn't
feel up to moving a 500# or so stone. Under load your "bedrock" might
move. If the jack it strongly fastened, it will not be the end of the
world. If the jack is just resting on it, a shift can cause a BIG problem.


But how to I rig up the jack? Do I have to build up a bunch of
wood (2 pieces this way, 2 pieces at 90 degree, and so on)
until I am high enough where the jack fits in under the ibeam?
Then jack it, adjust the posts?
That seems the obvious way to me.