View Single Post
  #2   Report Post  
RicodJour
 
Posts: n/a
Default

TonyT wrote:
Has anyone ever seen or heard of this problem: all 8 lally columns in
my basement are rusting/pitting/splitting. The house is 18 years old.
The basement has never had water problems (leakage or water on the
floor), but is somewhat damp. The rust is not only at the bottom of the
columns, but is distributed fairly evenly from top to bottom. The rust
seems to be starting in areas that look like pits and radiating out
from there. Sometimes there is water oozing from the center of the
pits that looks like it could be coming from the inside.

A corrosion expert from the Port Authority of NY/NJ has told me that it
sounds like the columns may need cathodic protection, i.e, they are
forming a kind of electrochemical cell by reacting with the soil. I've
measured a voltage from the columns to the cold water ground of about
0.3 V. This seems too low to indicate the need for sacrificial anodes
and the like.

If someone has heard of this, is there anything I can do besides
replacing all 8? Do I need to worry about the same thing if I replace
them? How much would something like this cost, anyway?


Oozing columns...? Are the columns hollow pipe or concrete filled? If
you have pits working their way out, what you see is probably not
nearly as bad as the inside. I'd consider drilling a 1/4" hole a few
inches down from the top and using a borescope to check out what's
going on inside.

Replacement cost estimates could vary substantially depending on
whether the columns are embedded in the slab, bolted or welded to the
beam, availability of your local qualified contractors, etc.

ZRC is a pretty big name in the corrosion coating business:
http://www.zrcworldwide.com/
Check out the cold galvanizing coatings.

R