How to Effectively Solve Efflorescence Issues on Raw Cement Walls – A Professional Guide

I. Understanding Efflorescence on Cement Walls

Efflorescence refers to the white powdery deposits or crystalline formations that appear on the surface of raw cement walls. These deposits result from soluble salts (mainly alkaline substances) within the cement that migrate to the surface with moisture. This not only compromises the appearance of the wall but can also impact the effectiveness of subsequent finishes.

II. Causes of Efflorescence

1. Moisture Penetration:

   • Moisture from internal or external sources dissolves salts and carries them to the surface, where they crystallize upon drying.

2. Material Quality Issues:

   • Sea Sand Usage: Using sea sand, even after rinsing, can leave residual salts, leading to efflorescence.
   • Subpar Construction Materials: Other materials containing excess salts or impurities increase the risk of efflorescence.

3. Poor Construction Environment:

   • Working in high-humidity conditions increases the chances of moisture seepage and efflorescence.

III. Steps to Solve and Prevent Efflorescence

1. Surface Cleaning:

   • Use a stiff brush or sandpaper to remove any visible powder or deposits.
   • For stubborn stains, wipe the surface with a diluted acidic solution (such as 5% vinegar), followed by a thorough rinse with water.

2. Address Moisture Sources:

   • Inspect Waterproofing: Ensure there are no leaks in the wall’s waterproofing layer.
   • Improve Ventilation: Reduce indoor humidity levels through proper ventilation.
   • Repair Cracks: Fill any wall cracks to prevent further moisture intrusion.

3. Apply a Sealing Interface Agent:

   • Use Hanshi 339 Multi-Functional Concrete Sealer to seal the wall’s surface, preventing salts and moisture from leaching out.
   • Apply evenly according to product instructions to ensure full coverage.

4. Level the Wall (Plastering):

   • Mix Hanshi 130 with 425 cement to create a high-quality plaster.
   • Apply a 1–1.5 cm plaster layer to level the surface and ensure durability.

5. Apply the Final Coat:

   • Choose mold-resistant and moisture-proof paint or other decorative finishes.
   • Apply at least two coats for even coverage and long-lasting protection.

IV. Additional Decoration Options

1. Tile or Stone Cladding:

   • After treating efflorescence and leveling the wall, you can install tiles, mosaics, or stone cladding using Hanshi 130 mortar to ensure a strong and durable bond.

2. Waterproof Wallpaper:

   • Use waterproof wallpaper for both decoration and moisture protection.

3. Decorative Panels:

   • Install wooden or PVC panels with appropriate back-side waterproof treatment to extend their lifespan.

V. Conclusion

By following the steps outlined above, you can effectively resolve efflorescence issues on raw cement walls and proceed with your interior finishing projects. Ensuring that each step aligns with Hanshi 339 and Hanshi 130’s product guidelines will result in durable and aesthetically pleasing surfaces.