Sandstone cleaning and sealing in North Curl Curl

A North Curl Curl garden is often a stack of terraces held by sandstone walls, linked by stone steps and topped with a paved area facing the view. On the upper terraces, stone looks bleached and feels gritty, with salt bloom on the seaward faces. The middle walls carry lichen on their caps and dark streaks where water runs down from above. Near the bottom, especially on the lagoon side, paths and steps turn green and slippery in winter. Our technicians test cleaners on each of these zones, starting with the mildest that works, because over-cleaning weathered sandstone removes stone as well as dirt, and once removed it does not grow back.

Salt is brushed off dry before rinsing, so it is removed rather than redissolved into the stone. Lichen, algae and mould receive a biocide and time to work at the root, then a scrub with soft brushes. Rinsing is gentle, and we never use a turbo tip, which gouges sandstone. Iron stains from water seeping through walls are treated separately, with a poultice where needed. On a slope, water management matters as much as the cleaning itself: each level is bunded and water is lifted out with a wet vacuum before it can travel down to the street drains and on to the lagoon or beach.

Upper terraces and steps that drain well are good places for a breathable impregnating sealer, which reduces salt and grime uptake while letting the stone dry from within. A retaining wall holding wet soil stays unsealed, since sealing would trap moisture and salts and speed up flaking. Sealer goes on only after the stone has dried thoroughly and on a still day, as an onshore breeze can deposit salt and sand on a fresh application. Natural and enhancing samples go down side by side so you can choose the finish. We note what was used and suggest an annual water-drop check on the most exposed surfaces.