Close up terrazzo floor restoration, after final polishing.

At the link, Specialized Maintenance Service, LLC, of Horicon, Wisconsin restored a 125 year old terrazzo floor discovered beneath bar area shag rug. They performed a public service here, beyond restoration of an important historic element, because carpet in such an application is toxic and disgusting. But it brings up a question – – what is terrazzo? Most briefly, terrazzo is a bed of marble chips (or other aggregate), in some sort of ground and polished masonry pour. What that pour is has evolved with technology, as Portland cement and now epoxy has become available. Originally developed by marble workers as a cheap flooring, the marble fragments were set in clay and then hand finished with abrasive stones to flatten the surface. These basic techniques were further developed to produce a variety of effects. George Washington installed terrazzo at Mt. Vernon. Portland cement was not available then, but presumably it was for the bar floor install. Specialized Maintenance provides a brief but specific technical account of their work, at the link.

GSA guidelines, Restoration of Terrazzo

The National Terrazzo and Mosaic Association