Plan a historic terrazzo floor restoration (regrinding and repair)

Steps

1. Assess crack severity and prior repairs first — GSA's historic preservation technical procedures classify hairline cracks (roughly under 1/32") differently from structural cracks that require engineering evaluation before any regrinding proceeds.
2. Follow a staged grinding/polishing sequence with progressively finer grit stones/screens to expose aggregate and remove haze without over-thinning the historic topping, using conventional heavy terrazzo grinding equipment rather than lighter floor machines.
3. Treat grinding off a layer of historic terrazzo as a measure of last resort — GSA guidance flags this as requiring specialist consultation given the risk of exposing the underlying mortar bed or over-thinning an already-thin historic topping.
4. On federally-associated historic properties, secure approval from the applicable historic preservation reviewing authority before regrinding, consistent with GSA's documented process for historic terrazzo work.
5. Match epoxy grout/patch repairs and any re-densifying/sealing products to the original aggregate and matrix color as closely as possible, then reseal per current NTMA maintenance guidance.