What sandstone cleaning costs in Sydney (and why no two walls price the same)
Sandstone cleaning in Sydney is priced per job, not off a square-metre rate card. The number turns on four things: the age of the stone, how deep the lichen has gone, the run of wall, and whether you add a breathable seal. Schmick's instant quote reads those inputs and returns a firm, bookable price in about 60 seconds.
Every wall prices as its own job
There is no square-metre rate card for sandstone, and any company handing you one has not looked at enough walls. A 1920s retaining wall on the North Shore and a 1990s veneer fence in the same street are different jobs. The old stone is softer. It has weathered faces, open pores and a century of biology in it. It needs gentler chemistry, lower pressure and more time. That is why Schmick quotes this work per job, not off a chart.
Age is the first input. Fresh-sawn stone still has its quarry skin — dense, tight, forgiving. Stone that has sat in Sydney weather for eighty years has lost it. What remains is softer than most owners expect; some of it will scratch under a thumbnail. Cleaning it well means matching the method to the stone in front of you, and that judgement is what the job is priced on.
Lichen depth and wall run do the rest
Lichen is not a surface film. A young colony lifts with a soft wash and a rinse. An established one has sent holdfasts into the pore structure, and killing it is a staged job — treat, wait, treat again — rather than a single pass. The deeper the growth, the more rounds the chemistry needs and the longer each metre takes. Depth of growth is the second thing the price reads.
Then geometry. A two-metre garden edge and a forty-metre boundary run are not the same afternoon. Metres of face, height and equipment access all scale the labour. The last input is optional: a breathable seal, applied only to sound, dry stone, which slows regrowth and keeps moisture moving through the stone rather than trapping it. Add it or skip it — the quote prices both ways.
Cheap blasting is the expensive option
The worst money you can spend on sandstone is a cheap high-pressure clean. Blasting strips the hardened outer face the stone spent decades forming. What sits underneath is softer and more porous, and it starts weathering faster the day the operator drives off. The wall looks bright for a season. Then it frets, powders and holds grime deeper than it did before. You have paid to shorten the life of your own wall.
Salt makes it worse. The NSW Heritage salt-attack guide documents how soluble salts decay sandstone and masonry — salts ride in with moisture, crystallise near the surface and push the stone apart grain by grain. The same guide warns against blasting affected stone, and against sealing it, because a film that cannot breathe traps the salt inside where it does its damage. Repair at that point is a stonemason's invoice, not a cleaner's. Gentle methods exist precisely so you never have to write it.
What cleaning cannot fix
Cleaning will not put stone back. If a wall is already fretting — faces falling away, sandy drifts at the base — a careful wash will make it cleaner, not sounder. Salt damage that has hollowed a block needs a stonemason, and often a drainage fix first. We will say so when that is what we are looking at, because cleaning over a moisture problem is a cosmetic answer to a structural question.
What cleaning does do is buy time and show the truth. It removes the biology that holds moisture against the face, slows regrowth, and returns the colour the stone actually is. On sound walls, that is most of the battle. On borderline walls, it shows you exactly what condition you own — worth knowing before you spend real money in either direction.
Your wall, your number, about 60 seconds
Because every wall is its own job, the only honest price is one built from your inputs. The Schmick instant quote asks about the stone, the growth, the run and whether you want the seal, then returns a firm, bookable price in about 60 seconds. It holds unless the place is materially different from what you described. No walk-around, no waiting on a callback that never lands.
If the sandstone shares a visit with windows, gutters or a house wash, bundling saves 5-15% across the lot. Sydney sandstone rewards patience — clean it gently, seal it only when it is sound, and leave the blasting to operators who do not have to live with the wall. Yours has been standing a long time. Price the work that keeps it that way.