VURA Robustner - SOLIDIFIER FOR NATURAL & CAST STONES

VURA Robustner – Stone Strengthening Solution

VURA Robustner is a single-component liquid consolidant based on ethyl esters of silicic acids. When applied, it reacts with atmospheric moisture and converts into silica gel (natural binder) and ethanol, strengthening the internal structure of the stone.

On application, 1 kg of VURA Robustner generates approximately 450–550 grams of silica gel, which binds and reinforces weakened mineral substrates from within.

Key Characteristics

• Ready-to-use, single component system
• Easy application on site
• Weather-resistant and non-yellowing
• Low viscosity for deep penetration
• High active content for effective consolidation
• Does not block pores – substrate remains breathable
• Transparent and colorless – suitable for light-colored stones
• Solvent-free formulation

Where It Is Used

Suitable for strengthening:

• Natural stones: Sandstone, limestone, tuff stone
• Cast stones: Stucco, fresco surfaces
• Heritage and restoration structures
• Weathered or friable stone substrates

The treatment does not alter the natural appearance and preserves the stone’s vapor permeability.

Application Guidance

1. Surface Assessment (Critical Step)

Before application, evaluate the condition of the substrate:

Salt Contamination Check

• Check for nitrates, sulphates, and chlorides
• High salt content must be reduced through controlled water cleaning
• Avoid pressure washing – it can damage weak substrates
• In fragile cases, partial strengthening before cleaning may be required

2. Identify Depth of Damage

For effective consolidation, treatment must penetrate beyond the weak layer.

Method (Practical Site Approach):

Higher absorption = higher damage.

3. Cleaning

• Use appropriate cleaning method based on substrate
• Rinse thoroughly with clean water
• Ensure no residues remain

4. Trial Application (Recommended)

Before full-scale work:

• Prepare a 1–2 sqm sample area
• Evaluate:
  • Consumption rate
  • Penetration depth
  • Strength improvement

This step reduces site risk. Skipping this usually leads to inconsistent results.

Working Principle (Simple Explanation)

Important Site Notes

• Works best on absorbent substrates
• Not suitable for non-porous surfaces
• Surface must be clean and dry before application
• Performance depends on depth of penetration, not just surface coating

Outcome

• Strengthens weak and powdering stone
• Maintains natural appearance
• Preserves breathability
• Extends life of stone structures