INFOMENTENANTA

Cleaning natural stone-clad surfaces

Cleaning natural stone surfaces covers a range of tasks aimed at:

• removing dust from the surface

• removing water and other liquids that contaminate the cladding

• eliminating residue

Specialized detergents are used as cleaning agents, chosen based on:

• the type of stone,

• the finish,

• the type of dirt,

• how contaminated the surface is.

What you should know before cleaning

Based on their composition, rocks fall into 2 categories:

• siliceous rocks (granite, slate, sandstone, quartzite) – relatively resistant to corrosive agents

• calcareous rocks (marble, travertine, limestone, onyx) – sensitive to corrosive agents.

Broadly, finishes fall into:

• polished finishes – easier to clean

• matte finishes – need more intensive cleaning due to the rock’s higher porosity.

• unpolished finishes (flamed, antiqued, bush-hammered, split-face, brushed, etc.) – need more intensive cleaning due to the rock’s higher porosity.

Dirt on a clad surface can come from:

• aggressive factors (post-construction cleanup, hardened adhesive and grout residue),

• environmental and traffic factors, specifically dirt that builds up while the surface is in use

Contamination level relates to:

• how persistent the dirt is

• how deeply it’s embedded in the surface.

How to clean

Detergents are applied directly to the surface by spreading them on, and generally left to work for 5-20 minutes. Many are diluted at a rate depending on how dirty the surface is, following the manufacturer’s specifications on the packaging and usage instructions.

Once the applied product has had time to work, the surface is scrubbed thoroughly with a brush or sponge, depending on the finish and how dirty it is.

In the final step, the surface is washed thoroughly with clean water to remove residue.

Cleaning surfaces by rock type:

• Surfaces clad with granite, slate, or quartzite, regardless of finish, are cleaned with acidic-pH detergents, which are effective and compatible with the surface. We recommend Grout Stain Remover. Note: for polished and matte finishes, compatibility tests are needed, since certain stone varieties can react differently to this type of detergent. Finding the right dilution can prevent an unwanted reaction with the stone.

• Surfaces clad with marble, travertine, limestone, or onyx, with a polished or matte finish, are cleaned with Power Stripper or given mechanical treatments.

• Surfaces clad with marble, travertine, limestone, or onyx, with an unpolished finish, need more precise analysis and recommendations, since results depend on the stone variety and the detergent’s dilution level. A test on a hidden area can clarify how the surface will react.

Regardless of stone type and finish, we recommend cleaning before sealing with Grimex or Power Stripper, depending on the type and level of contamination:

• For general cleaning (including light degreasing), removing dirt from traffic and everyday use, we recommend Grimex.

• For deep cleaning, needed for heavily contaminated surfaces (e.g. mineral oil residue), we recommend the professional detergent Power Stripper.

• To remove residue from old stone sealants or coatings, we recommend the specific detergent Solvex.

For removing certain unusual stain categories, we recommend consulting a PIATRAONLINE specialist.