Before you try anything: always speak to a professional before cleaning, treating or applying any product to your stone. Every slab is different, and the wrong product can cause permanent damage. Contact us or a qualified stone restorer first.
Quick answer
Rust stains in terrazzo need a rust-removing poultice made specifically for concrete and stone, applied thickly, covered and left to dry. Never use an ordinary acidic rust remover on terrazzo: it will lift the rust and etch the surface at the same time.
First, check what you are dealing with
- Orange or brown ring the shape of a can or tin: rust transfer.
- Orange spots with no obvious source: possibly iron within the stone. Ask a restorer.
What you need
- Stone-safe rust poultice
- Plastic wrap and tape
- Plastic scraper
- Gloves
Step by step
Remove the source
Take away the can, tin or metal object and wipe the area with warm soapy water.
Apply a stone-safe rust poultice
Use a rust remover labelled safe for concrete, following its instructions. Most are applied thickly and left to dry.
Cover and wait
Cover with plastic, tape the edges and leave for the time on the label, usually 24 hours.
Remove and assess
Scrape off with a plastic scraper, rinse and dry. Repeat once if needed.
What not to use on terrazzo
- Vinegar, lemon juice or "natural" citrus cleaners: they etch terrazzo.
- Scourers, steel wool and abrasive creams on a polished surface.
- Mixing cleaning chemicals, especially bleach with anything else.
- Household rust removers and oxalic or hydrochloric acid products.
When to call a professional
Deep rust, or rust that seems to come from within the stone, needs a restorer. A terrazzo specialist can re-grind, hone and polish the surface and replace missing chips.
Understanding rust stains on terrazzo
Cement terrazzo is porous in its binder, so stains often appear as a halo around the chips; epoxy terrazzo absorbs far less.
A terrazzo specialist can re-grind, hone and polish the surface and replace missing chips.
Good to know
In cement terrazzo, both the binder and any marble chips can be etched by acidic rust removers, so use a stone-safe product.
Stop it happening again
Whether yours is cement terrazzo and epoxy (resin) terrazzo, repairing it fixes today's mark; protecting it stops the next one. Our clear Stone Protection Film sits over the surface, so acids cannot etch it and liquids cannot soak in. Choose Gloss for polished terrazzo or Matte/Satin for honed and matte finishes. The protection is identical. It is installed across Sydney with a 10-year written warranty.
How we protect terrazzo · Stain removal guide · Rust stains on every surface