Heritage Sandstone Facade — Graffiti Removed Without Stone Damage

The brief

A Sydney heritage-listed sandstone facade was hit by spray-paint taggers over a long weekend. Three tags across about 40m² of weathered sandstone. Council heritage rules prohibited acid wash, pressure washing or chemical strippers. The conservator’s advisory was clear: dry ice, or chip-and-replace stone (the latter being prohibitively expensive on listed work).

We were brought in following a sample-area test request from the heritage architect.

The work

Sample test. Before any work was scoped, we ran a 0.5m² sample on an inconspicuous lower corner. Conservator and heritage architect on site to inspect. Pressure tuned at 50-60 PSI with a 60-degree fan nozzle. The sample came up clean — paint lifted, sandstone surface unmolested. Sign-off given.

Main work. Worked the three tags in sequence over a single day. Lower-pressure technique throughout — heritage stone is more forgiving than paint or steel for this kind of cleaning, but the surface texture must be preserved exactly.

Documentation. Pre/during/post photos at every 1m² grid square. Conservator visited once during the work and once at sign-off.

The result

All three tags removed cleanly. No ghosting visible from a normal viewing distance — and on close inspection, the original sandstone weathering pattern was preserved. Mortar joints intact. Heritage architect signed off on completion.

Council has since added us to their preferred-supplier list for heritage cleaning work. We’ve worked on six further heritage projects under that arrangement in the year since.