Kitchen · DIY guide
How to clean and seal a stone benchtop
Natural stone — marble, granite, limestone — is porous and needs sealing. Engineered stone generally does not. Sealing a benchtop that does not need it wastes an afternoon; not sealing one that does leaves you with a permanent oil mark next to the cooktop.
Legal to DIY in Victoria
What you need
- A water test (free — see step 1)
- Impregnating stone sealer suited to your stone
- pH-neutral stone cleaner
- Lint-free cloths
- Gloves and good ventilation
Step by step
Test whether it needs sealing at all
Drip a tablespoon of water onto an inconspicuous area and leave it 15 minutes. If the stone darkens where the water sat, it is porous and needs sealing. If it beads and the stone does not darken, the existing sealer is still working. Engineered stone almost never needs it.
Clean thoroughly with the right product
pH-neutral stone cleaner only. Vinegar, lemon, bleach and most supermarket sprays etch natural stone — the dull patch is a chemical burn in the surface, not a stain, and sealer will not hide it.
Let it dry completely
At least a few hours, longer in winter. Sealer applied over moisture will haze and it is unpleasant to remove.
Apply the sealer thinly and evenly
Work in sections of about a square metre with a lint-free cloth. Keep the surface wet with sealer for the dwell time on the bottle, usually 5–15 minutes.
Buff off every trace of residue
Before it dries, buff the surface dry with a clean cloth. Sealer left to dry on the surface leaves a streaky film that is genuinely difficult to remove. This is the step that matters most.
Wait before using it
Most sealers need 24 hours to cure. Keep the bench clear and dry for the full time.
Common mistakes
- Sealing engineered stone that never needed it
- Using acidic or bleach cleaners on natural stone
- Letting sealer dry on the surface
- Sealing over an existing stain — it locks it in permanently
When to stop and call someone
Chips at the edge, cracks around the sink cutout, or a failed join between slabs need a stonemason. So does an etch mark in polished marble — that is a re-polish, not a clean.