On 12 Nov 2006 16:37:02 -0800, "Jeff" wrote:

Hi,

Half of our basement was dug down about 6 inches more than 30 years
ago. I just pulled down some wall panelling in the dug-out section, and

discovered that there is about a 4 inch gap between the bottom of the
foundation wall and the basement floor. I can clearly see earth fills
this gap.

Here are a couple of photos of the gap:

http://jjlloyd.googlepages.com/basement

The house was built in the 1920s, and the foundation is poured
concrete. The basement floor is poured concrete. The earth is very
sandy, and we do not have a problem with water via the gap. There are
no cracks in the foundation wall, nor are there cracks in the exterior
brick of the house to suggest bad settling. I have only uncovered a
small section of the walls so far.

I've had a couple of contractors in who suggest an expensive "proper"
addition of footings. Another contractor suggested the earth be dug out

several inches past the exterior of the foundation wall, and
back-filled with concrete to make a sort of 1/2 footing. Or I was
considering just filling in a few inches of concrete on the inside to
prevent the earth from spilling inwards. But I don't believe that will
add any structural support.

Do I really need expensive several-feet deep footings with weeping
tile, etc., to replace the earth that hasn't moved much in all this
time?

Any opinions are appreciated.



If it hasn't moved in 30 years, the chances are it's not going to,
at least until the next earthquake, flood,
If you WANT to fix it, there is a range of choices, trading off
how much space in the basement you're willing to give up,
how much money you're willing to spend, how much time and effort
you're willing to put in, and whether you want to involve
your local authorities and/or contracters.

If you trench just a few inches into the slab, and pour
a knee-wall up against the base of the existing wall,
you only have to make the knee-wall in a way that
will keep it from rolling. THat will be structurally
sufficient until and unless the soil outside the
wall actually liquifies, which is unlikely. It
won't be waterproof, though.

Failing that you could use timber jacks to take the weight
off the house, drive pilings sideways into the dirt under the
existing wall, and excavate 2' to 4' sections and pour footings
under them. (In that scenario, you'd use expanding concrete)
How big a chunk you do at once in that case depends on
how big a hole you think the wall will span without
support while you're working. I don't think I'd be
willing to try that with a rubble wall, but from
the picture, you've got monolithic concrete, right?

This latter is essentially the same thing you'd do if
you were trying to put a window in, but you're putting
them is really low, and filling them with concrete
afterwards.

--Goedjn