Sandstone cleaning and sealing in North Bondi

Sandstone on a North Bondi property usually works in tiers. Retaining walls hold the slope, stairs climb between levels, and paving or a terrace at the top takes the view and the weather. The ocean-facing stone shows salt in two ways: a dull grey crust when it is building up, and fine grains or thin flakes on the ground when it has been there too long. Lower tiers stay wetter and grow algae. Older Art Deco blocks add sandstone fences and entry steps worn by ninety years of residents. We look at each tier before quoting, because each one usually has a different problem.

Salt is removed before anything else, starting with dry brushing and vacuuming, then poulticing where it has soaked deep into a wall or step. Moss, algae and lichen are dosed with a stone-safe killer that stays on for the full label period, so the result survives the next wet winter. Rinsing is done with a wide, gentle fan or warm water at modest pressure, since weathered coastal sandstone sheds grains under any concentrated jet. On a sloping block we work from the top down and catch wash water at every level with bunds and a wet vacuum, so none of it runs down the driveway or across the footpath toward the beach below.

Sealing suits the exposed horizontal surfaces: terrace paving, stair treads and the tops of walls. A breathable impregnator lets rain bead off and slows salt uptake while still letting the stone dry out from inside. Retaining walls with soil behind them are usually left unsealed. We show natural and enhancing samples on your own stone before you choose, apply the sealer only on a calm, dry day, and write down the product and areas treated. Ocean-facing sandstone in North Bondi tends to need its protection checked more often than inland stone, so drip a little water on the terrace every year and watch whether it beads.