Features of problem
The Efflorescence problem is a phenomenon where most white solids form on plastered walls and concrete walls. The white Efflorescence may be found on the flowing surface. It usually comes out along the cracks of the wall, wall joints or grout joints.
The Efflorescence is usually removed prior to painting in order to strengthen the adhesion between the paint film and the surface. However, if the Efflorescence have already formed but happens under the paint film because it cannot evaporate through the pores of the paint film, the Efflorescence will equate and push the paint film to cause various paint problems.
Causes
Usually, cement walls contain alkali and salt as constituents as a result of the reaction between cement and water, mixing plaster which does not meet the required standards or not leaving the cement to fully curing. When the cement is exposed to the weather causing cracks on the wall, the water can seep into the wall to dissolve the salt and alkali that have accumulated in the cement. Then, it evaporates and precipitates on the paint film and destroys the paint film.
But for some paint films that do not allow salt water from inside the wall to pass through to evaporate to the outside, it will cause Efflorescence under the paint film. These Efflorescence will accumulate and push the paint film causing the paint problems such as blistering, peeling, fading or dusting.
How to solve
1. Clean all the stains using the Water Jet to spray and then leave the surface to dry completely before working on the next paint job.
2. The surface must not have cracks. If any, cracks must be repaired with quality material prior to coating. Where cracks are less than 2 mm in size, cracks are repaired with Nippon Paint Vinilex Wall Putty. For cracks larger than 2 mm, fill with Terracryl.
3. For the areas with moss and fungi, scrub with Nippon Paint Vinilex Biowash fungicide and apply Nippon Paint Vinilex Biowash fungicide. Leave it overnight. The surface before painting must be clean and completely dry. If following Nippon Paint standards, the moisture content must not be more than 6% by Kett model HI-520 or not more than 14% by Protimeter Mini and not more than pH 8.
4. Apply 1 coat of old plaster primer (recommended paint system for exterior: 1 coat of Old Cement Primer, Nippon Paint Excel Primer, recommended paint system for interior: 1 coat of Nippon Paint Water-Based Primer Aqua Sealer) and 2 coats of Topcoat (Recommended colour system for exterior: 2 coats of Nippon Paint Weatherbond, recommended paint system for interior: 2 coats of Nippon Paint Aircare).
How to prevent
Colour paint according to the correct steps must pay attention to the surface preparation process. The surface before painting must be clean free from dust, dirt, grease and other foreign matter and completely dry without cracks to prevent water and moisture from seeping into the wall and the cement wall should be allowed to fully curing.
For surfaces requiring excellent alkali and salt resistance, the primer that prevents alkali and salt should be chosen from damaging the paint film. There are both water-based formula and oil-based formula. Normally, the oil-based formula is more durable than water-based formula.
Water-based primer: 1 coat of Nippon Paint 5100 Wall Sealer
Oil-based primer: 1-2 coats of Nippon Paint Tylelac Trans Sealer
Topcoat for exterior: 2 coats of Nippon Paint Weatherbond.