1. In Italy this supposedly lasts hundreds of years. Are there any special chemicals used for exterior application. So far I only heard of people covering the plaster with wax. Wouldn't other sealers work out better to protect the plaster?
2. I faintly remember reading venetian plaster even in a pool, I never thought it was waterproof or am just willing to believe I read something wrong. If not, shouldn't this stuff be good for metal bars in highly corrosive areas?