mm wrote:
On Wed, 20 Jun 2007 22:07:07 GMT, Ken wrote:

Phisherman wrote:
I have a 3x4' concrete stoop just under the side garage door. Since
1992 it has been sinking. About 1997 I dug under it, used a car jack,
and put rocks underneath. It has been sinking and now is 6" below
were it was. I'd have to remove some landscaping to repeat what I did
in 1997. Is there an easier way? I can't be sure if the land is
sinking or the builder buried refuge that is now decaying.
For what it is worth, I helped a neighbor who had a front 20 foot porch
of concrete start sinking. We place several hydraulic car jacks under
the porch with concrete bricks under the jacks. When the bricks stopped
sinking and the porch reached the point when it was level, we removed
one of the jacks and wedged more concrete bricks under the porch to fill
the space. Of course we repeated this procedure with the other jacks.
This was twenty years ago, and the porch is still level. The key I
believe is getting the bricks to sink until the reach a stable place.
Once they do, they will serve as a footing.

How long did the sinking part take, after you started the repair?
Did rainstorms make a difference?

I am not sure if your question is for me or the original poster? In my
case the sinking of the original porch took several years, getting a
little worse each year until it needed to be addressed. The jacking and
blocking effort only took a few hours with a few neighbors helping with
the job. We laid a long flat board across the porch so that we could
see we were not stressing one side more than the other and cause it to
fracture. It really turned out better than we had expected.

As for aemeijers comment about using the proper tools, that is always
the best approach. In our case it was a "What have we got to lose?"
approach. It most likely would have been a case of replacement rather
than hiring a service to jack up the porch. Also, the way the porch was
laid over the brick sides meant there was little chance of someone
having it fall down on their limbs. We were well aware of safety and
not about to volunteer to a project where we wish we had not, even if
there was free beer.