Features of problem

The problem of hairline cracks is the occurrence of cracks on the plaster surface or skim coat walls in the size of not more than 0.5 mm. If it is left for a long time and does not rush to correct, this may result in the house or building looking even shabbier. Water can seep into the cracks resulting in paint problems such as fading, low paint adhesion, etc.

Causes

The problem of hairline cracks can be found both inside and outside the buildings. There are several reasons for the occurrence as follows:

It can be caused by lack of water in plaster. Because the masonry wall is too dry, when starting plastering work, the water mixed in the plaster in a good ratio loss water to the inner wall causing the plaster to be in the wrong ratio and too dry. It cause cracks. Moreover, when the brick wall is finished and plastered without waiting for the brick wall to set, it can cause cracks.

It is also often found in walls that are plastered with lightweight bricks. The reason is that the lightweight bricks have more stretch and shrinkage than general bricks due to the large number of internal pores causing the plaster surface to stretch and shrink until the cracks occur.

Different temperature and environment of outside and inside the house cause the plaster surface to stretch and shrink and cracks can occur as well.

How to solve

1. Check the severity of the plaster to see if it still sticks to the wall or not by knocking on the wall. If there is a sound, then the plaster is not sticking to the wall. The plaster should be extracted and plastered on the wall again. However, if knocking and the sound of the wall is still tight, repair to cover the cracks in the next step.

2. Repair the hairline cracks by making the groove wider. The ool as the angle of the trowel or a flat screwdriver can be used to cut into a V-groove, width 1-2 mm. When finished, clean the dust on the wall thoroughly. Then fill with Nippon Paint Vinilex Wal Putty. For cracks larger than 2 mm, fill with Terracryl Acrylic Filler if the wall has moved slightly. This type of material is flexible causing no recurrence of cracks. If the putty collapses, it can be repeated more. Let it dry before applying the system paint.

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 alkalinity must not be more than 8 (pH 8).

4. If the old surface is very deteriorated, paint 1 coat of old cement primer first (Old Cement Primer, Nippon Paint Excel Primer) and/or use a flexible primer to prevent future hairline cracks. Paint 1-2 coats of FlexiSeal. Then paint 2 coats of topcoat (Recommended paint system for exterior: 2 coats of Nippon Paint Weatherbond, Recommended paint system for interior: 2 coats of Nippon Paint Aircare).

How to prevent

For cement mix, it should be mixed in the correct proportion or choose for ready-made cement such as general plaster, which has been mixed correctly. This should be plastered properly and the plastering process must be of good quality.

Before constructing the wall, the brick should be soaked in water and when the wall is finished, the water should be cured (sprinkle water on bricks) for at least 7 days to prevent bricks from absorbing water from the plaster. After that, plastering works start.

Paint work 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.

For surfaces with hairline cracks, when the wall is repaired, choose the flexible primer system that can cover up hairline cracks to make the wall smooth.

Flexible Primer: 1-2 coats of Nippon Paint FlexiSeal.

Topcoat: 2 coats of Nippon Paint Weatherbond

Explore more

Fungus and algae

This occurs in locations with a high moisture accumulation. Fungus & Algae stains are frequently found in the stream.

Poor Hiding

This can occur for a variety of reasons, including skipping the primer phase prior to applying the main colour.

Roller Mark

One of the important factors in painting a beautiful and smooth paint film apart from having a good surface is the painting equipment.

Dirt Pick-up

Dirt left on the paint coating. Can be found as a flowing stain on waterway.

Efflorescence

Caused by solid flowing out of the wall’s cracks, joints,or grout.

Low Paint Adhesion

This happens between the dry paint film and the surface on which the paint film adheres.

Fading Colour

It usually occurs with exterior paint that is exposed to weather conditions such as sunlight, where light will gradually destroy the paint film.

Blistering

It usually caused by the loss of adhesion to the wall so that it blisters out. It is found a lot from the moisture problem.

Touch Up Problem

Occurs when the shadows of the colors overlap cause uneven color surface.

Chalking Surface

It often occurs with exterior paint exposed to outdoor weather condition or walls that have been used for a long time in high humidity.