Cleaning & sealing limestone benchtops

Limestone Benchtops — Cleaning & Sealing Tips

Limestone presents some very challenging scenarios when used as a benchtop. It is important to understand this in view of your communication with your client so that their expectations are realistically aligned with the limitations of the stone. These can be summarised as follows:

Calcite composition

Acid Sensitivity – Limestone typically contains at least 50% calcite or calcium carbonate content and is of biological origin. This composition means that it is the most sensitive of all natural stone types to acid attack. In the case of a bench top this relates to sauces, wines, beverages, lemons, many fruits and vinegar

Absorption – Limestone has an absorption rate from as low as 0.6% to as high as 30%. Normally, limestone absorption is 3% to 12% .

Ability to be sealed – Limestone, because of it’s inert calcite structure is widely regarded as the most difficult stone to seal. Actichem have developed a unique water repellent penetrating sealer namely Defender CSD50 which is highly recommended for wet areas or outdoor use.

Penetrating Sealers

To preserve the natural appearance, texture and colour of stone, mostly they are sealed with sub- surface, penetrating sealers. These special protective treatments also allow the stone to “breathe”. The limitations of penetrating sealers is that they do not provide “bullet-proof” protection. The provide a powerful oil and water repellent surface which holds staining agents out of the stone. However, some staining agents if not removed can still create permanent staining. In contrast film forming sealers change the texture and appearance of natural stone but provide a total block to staining agents.

It should be noted that

• Sealed limestone surfaces can still be stained by acidic agents within 5-10 minutes. Especially red
  wine, vinegar and lemon juice.
• Mostly oil staining agents are completely blocked for at least 24hours.
• General grime, sugar and water containing foodstuffs are completely blocked for at least 24hours.

The two main options when it comes to protecting limestone.