Is water-based construction difficult? If these common problems are not solved, no matter how good the effect is, it will be in vain!

Water-based multi-coated coatings such as Water-in-Water (WiW) and Water-in-Sand (WiS) have become ideal alternatives to natural stone and ceramic tiles for exterior wall decoration. With excellent features including lightweight structure, environmental friendliness, weather resistance, and rich color options, these materials are widely used in high-rise buildings, commercial complexes, and renovation projects. Compared to traditional materials like stone cladding and real stone paint, WiW/WiS significantly reduce structural load while offering superior aesthetics and long-term durability. They are compatible with various substrates such as concrete, ALC panels, and PC boards, making them suitable for both new construction and retrofitting applications.

To ensure optimal performance and appearance, the application process must follow strict standards and detailed steps:

• Surface Preparation: Remove dust, grease, and loose particles from the base wall. Repair cracks and hollow spots with exterior putty and cure for 5–7 days. Use high-pressure water washing for heavily soiled surfaces.

• Putty Application & Sanding: Apply flexible grey putty in 1–2 coats, ensuring surface flatness. Grind the dried putty with wet sandpaper to eliminate burrs and unevenness. Cure the putty layer for 15–20 days until the moisture content is below 10% and pH value is less than 10.

• Primer Coating: Evenly apply 1–2 coats of specialized sealing primer with a roller or spray gun, paying special attention to corners, window/door edges, and recessed areas to prevent peeling.

• Basecoat & Topcoat Spraying: Spray WiW or WiS coatings with a dedicated spray gun. For WiW, use a 3.0mm nozzle; for WiS, use 3.5–4.0mm. Apply 1–2 coats with at least 12 hours between layers. After 24 hours of drying, apply 1–2 coats of matte clear topcoat to enhance weather resistance and color retention. For architectural details like cornices, spraying is preferred over rolling to avoid mottling.

• Curing & Site Cleanup: Allow the coating to fully cure for at least 7 days without physical damage. Remove protective films and clean the site within 24 hours after completion.

During application, several common issues may occur, which can be addressed with proper control and planning:

• Whitening (Blushing): Often caused by insufficient drying or low-quality topcoat. Ensure the base coat is fully dry before applying the topcoat and use high-performance clear coatings.

• Cracking: Usually due to poor substrate crack resistance. Use crack-resistant mortars, alkali-resistant mesh, and compatible primers for better performance.

• Uneven Spraying or Mottling: Caused by improper spraying techniques, weather conditions, or partial touch-ups. It is recommended to reapply the entire affected area rather than spot repair.

• Equipment Corrosion & Pitting: Water-based coatings may corrode iron equipment and cause pitting. Use stainless steel tools and control the flow rate during application.

• Poor Film Stability: High or low humidity can affect film formation. Avoid application in extreme weather conditions.

• Layer Separation During Storage: Due to density differences between phases, the product may separate over time. Choose high-stability products and avoid long-term storage without stirring.