I had the same problem and significant rust had developed before I
Here's what I did:
- Firstly, you must (MUST!) remove ALL rust at the tower/concrete
interface. I used a star drill to dig into the concrete until nice shiny
galvanized tower was visible all around all three legs. Then I (actually
KF3P) sandblasted the legs until nice shiny steel showed thru every place
where rust was previously present.
- Next, I used cold galvanize paint to coat the bare shiny steel, then a
second coat the next day.
- Next, I applied a Rustoleum primer intended for galvanized steel (I
understand they have changed the name, but the paint and primer were
then known as Galva-Grip). I then applied the finish coat of
Galva-Grip paint (not primer). I also allowed the primer and paint to
coat the nearby concrete foundation so that it created a seal around the
- Lastly, I used "GE Silicone II" Concrete seal to thoroughly seal the
concrete/steel interface from the weather. It adheres very well to
concrete and steel.
Like you, I considered using a layer of concrete, but
rejected that approach for the same reasons u did!
Be sure you re-grade the area around the tower base so mud can never
collect on the tower foundation again! And inspect the foundation