Thanks to all who replied to my question! Every reply is greatly
appreciated. There were many direct as well as on the list.
Several suggested my base must be moving if I'm having seasonal
problems. I don't think so. It's the surrounding soil that raises up
2 to 3 inches in winter, while the base stays put. I can see the
same happening at other locations near the tower where bedrock
breaks through the surface. In summer the flat bedrock is level with
the surrounding soil. In winter the bedrock is 2 to 3 inches lower
as the soil has heaved upward around it.
It may be the only reason for extending the base is cosmetic. I
was/am concerned about the dirt and debris around the tower legs
rotting it more quickly based on my (possibly incorrect) perception
that towers seem to rust more quickly when in contact with grass,
dirt, tree branches, etc.
By far the most common suggestions were either cleaning the existing
concrete and then coating with a special adhesive before pouring a
new layer on top, or an additive to the new concrete to help it
stick to the old stuff. I am looking into both, but suspect my
chances of getting this material where I live may be slim. Many also
suggested the new layer should be tied to the old with rebar, which
seems like a good idea in any case.
I will give the feasibility of the project some more thought while I
continue to search for the proper bonding agent(s).
Thanks & 73,
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