People who have been inside this building and the pictures they took confirm that it is of solid concrete construciton. This may account for why it's still standing after so many years of neglect (and being flooded within my memory).

However, I do know that Thomas Edison was at one time a proponent of all-concrete construction. I will try to do some research to to see if his efforts match the date the building's construction (1913).

Thats funny you mentioned Edison...if I remember right from the Edison Winter Home Tour in Fort Myers, FL, the pool there was also all concrete and the tour guide said that he used Cement from a cement company he owned.