On 11 Jul 2020 20:50:51 GMT, F Russell wrote:

On Sun, 12 Jul 2020 06:19:20 +1000, Rod Speed wrote:


Depends on why it has subsided like that.


The house was built on this suburban lot about 60 years
ago.

The subsidence has been very slow. In fact it is a not an
uncommon occurrence. Concrete driveways sometimes subside
and there are companies that offer a "pump it up" solution
as a cheaper alternative to replacement.

I'm not concerned about sinkholes. I just want to know
if exposing 12-18" of the top basement wall poses any
problem.


This sounds like they back filled over the construction trash and it
is rotting away. Many years ago, this was not uncommon until building
departments started managing the construction trash. Now dumpsters are
required on site as soon as the first crew starts working along with a
porta potty, unless you are out in the boonies, beyond the permit and
inspection process.