Sandstone cleaning and sealing in Maroubra

Close to Marine Parade, Maroubra sandstone usually means the fences, piers and entry steps of unit blocks, plus garden walls and terraces on the houses in between. The ocean-facing faces show a grey crust and, on older stone, sandy edges where grains have loosened. Steps carry a polished track worn by sandy feet, and shaded paths go green. Near Maroubra Junction and along Anzac Parade, the same kinds of fence and step are darker with traffic film rather than salt. Before quoting, we look at where each surface sits relative to the beach and the road, and test a small area to confirm which method works.

On salt-affected stone we start dry, brushing and vacuuming loose salt and sand before introducing water, then rinsing with fresh water at low pressure. Deep salt in walls can be drawn out with a poultice. Shaded paths with algae are dosed with biocide and left alone for a while before rinsing. Traffic film near the Junction comes off with a sandstone detergent and soft brushing. We avoid acid entirely and keep concentrated jets away from the stone, because salt-weakened sandstone loses its surface quickly. Mats, bunds and a wet vacuum keep wash water out of the stormwater system, which in Maroubra drains toward the beach.

Sealing is worthwhile on most of the horizontal sandstone near the beach: steps, paths, terrace paving and the tops of fences. A vapour-open impregnator reduces how much salty water gets in and makes sand and grime easier to sweep away, while the stone can still release moisture. Walls holding back soil, and the lower courses of walls drawing ground moisture, stay unsealed. Samples are laid down first, then the product and areas are recorded for the owner or strata manager. In this exposure, resealing tends to come round sooner than inland, so drip water on the busiest surfaces every year and see whether it beads.