Microorganisms degrade protective coatings by producing organic acids and by excreting enzymes.
This project tests commercial coatings for their ability to withstand microbial attack and investigates the use of biocides as preventative ingredients in coatings. The wall contains 2,352 samples of stone 2,032 domestic stones from 47 states and 320 imported stones. Unexposed specimens have been stored indoors for comparison with now-weathered samples. Phase 1 of the project focused on photographic and descriptive documentation of the archived and exposed stone samples. In Phase 3, mineralogical and microstructural features will be correlated to stone performance, and compared to performance of similar stones from the same producer that have been used in building construction.