Sandstone cleaning and sealing in Manly Vale
Manly Vale sandstone rarely sees much salt, but it sees plenty of damp. We clean the growth out at the root and seal only stone that dries.
- Manly Vale 2093
- $20 million public liability
- Price on request
The sandstone we expect on Manly Vale properties falls into three groups. Front walls and fences on busier roads carry traffic film and a little lichen. Walls and paths on lower ground near Manly Creek and the reserves hold moisture, so they turn green and black, with moss in the joints. Retaining walls on the slopes rising toward Manly Dam can show white efflorescence where groundwater moves through the stone. Each group calls for a different mix of cleaner, dwell time and rinse, so our technicians trial a small area of each before committing. That keeps the result even and avoids using a stronger product than the stone needs.
For organic growth, we apply a biocide formulated for natural stone and leave it long enough to reach the roots, then lift the dead growth with soft brushes and a gentle rinse. Efflorescence is brushed off dry first, since wetting it simply dissolves the salt back into the wall. Traffic film comes off with a pH-neutral cleaner. We keep turbo nozzles and acid well away: the first scars sandstone, and the second reacts with its iron and leaves orange stains. Because this suburb drains to Manly Creek and on toward Manly Lagoon, the work area is bunded, rinse water goes into a wet vacuum, and we take it away for disposal.
Damp stone is where sealing needs most thought. Paving, steps and wall caps that dry between rain events usually benefit from a breathable, penetrating product, which keeps grime and growth at bay and shortens future cleans. Walls that carry groundwater or show efflorescence are better left unsealed, since a sealer would trap the moisture and salts behind the face and cause flaking. Sealing waits until the stone is dry right through, which in a shaded valley garden may take several fine days, and lay out natural and enhanced trial patches first. Where drainage is the root cause of a problem, we tell you that rather than selling a sealer.
Frequently asked questions
Sandstone questions we hear in Manly Vale.
Should we seal a wall that has white salt on it?
No. The salt shows moisture is moving out through the face. Sealing would trap it inside and the stone would start to flake. Clean it, sort out where the water comes from, then reassess.
Why do you avoid acid on sandstone?
Acid brick cleaners react with the iron minerals in Sydney sandstone and leave orange-brown stains that are harder to remove than the original dirt. Biocides and pH-neutral cleaners do the job safely.
Our path near the creek is slippery. Can sealing help?
Cleaning is what restores grip, by removing the algae. A penetrating sealer keeps the surface texture and slows regrowth a little, but regular maintenance in a damp spot matters more.
How do you dispose of the wash water?
It is recovered with a wet vacuum and taken off site for appropriate disposal, rather than being let into a drain or onto the ground.