Material guide
Bluestone restoration and care
Dense basalt, common in Australian paving and pool surrounds. Durable, but prone to iron spotting and coating failures.
Bluestone in Australia generally means basalt — a dense, hard volcanic stone used widely for paving, steps, pool surrounds, and cladding. It wears extremely well and is far less acid-sensitive than the calcite stones.
Its characteristic problems are cosmetic rather than structural. Iron inclusions within the stone can oxidise and produce rust spotting, and the small gas voids typical of basalt collect dirt. Sealer choice is also frequently the source of complaints: the wrong product on bluestone can leave a patchy, plastic-looking surface that is worse than the bare stone.
Bluestone is available sawn, honed, and flamed. Flamed and textured finishes are common externally for slip resistance and are not intended to be brought to a polish.
Behaviour
What makes bluestone different
These properties are the reason the method changes. They are not trivia.
- Dense and hard-wearing basalt
- Far less acid-sensitive than marble or limestone
- Contains natural gas voids that hold dirt
- Iron inclusions can oxidise and spot
- Commonly supplied sawn, honed, or flamed
Common problems
What goes wrong, and whether it can be put right
Described as you would notice it, then what is physically happening, then what restoration can realistically achieve.
- 01
Orange or brown rust-coloured spots emerging from the stone
- Cause
- Iron inclusions within the basalt oxidising as moisture reaches them.
- Outlook
- Often reducible with targeted treatment. Because the source is inside the stone rather than on it, spotting can return — an honest expectation to set upfront.
- 02
Patchy, blotchy, or plastic-looking appearance after sealing
- Cause
- An unsuitable or unevenly applied sealer, frequently a film-forming product on a dense stone.
- Outlook
- Correctable. The coating is removed and, if sealing is appropriate at all, a suitable product used.
- 03
Ingrained dirt giving a grey, tired look
- Cause
- Soiling held in the surface texture and gas voids, which ordinary washing does not reach.
- Outlook
- Correctable with appropriate cleaning method and equipment.
- 04
White haze or bloom, typically near pools and on new paving
- Cause
- Efflorescence — salts moving through the stone or bedding and depositing at the surface.
- Outlook
- Removable, though it recurs while the moisture path remains. Worth understanding the cause before treating.
Looking after it
Day-to-day care for bluestone
A good share of the damage we repair was avoidable. This is the short version of how to avoid it.
Do
- Rinse pool surrounds to limit salt and chemical build-up
- Use pH-neutral cleaners
- Choose breathable sealers appropriate to external basalt
- Keep steel furniture and fixings from sitting wet on the surface
Avoid
- Film-forming sealers, which are the usual cause of patchy bluestone
- Acidic rust removers used without testing — they can bleach the stone
- High-pressure washing on jointing and softer bedding
Finishes
Finishes achievable on this stone
The finish is chosen to suit the stone and the room it is in, not applied as a default.
- honed
- natural
- textured
- matte
Other materials
We restore more than one kind of stone
Looking for a particular job rather than a particular stone? Browse stone restoration by what needs doing.
Not sure what your bluestone needs?
Most bluestone complaints we attend are sealer problems rather than stone problems. If the surface looks patchy or plastic, the likely fix is removing what was applied — not adding more.