Hairline Crack on Skim Coat

Definition:
Hairline cracks are fine cracks on the surface of a skim coat, usually in the shape of a spider’s web or eggshell cracks.
Causes:
• Skim coat material dried too quickly.
• Changes in temperature and surface.
• Application of skim coat during hot or windy conditions causes skim coat to dry too quickly.
• Poor adhesiveness of skim coat.
• Plaster layer contains high amounts of sand and mud which causes shrinkage.
Solutions:
• Use Mowilex Alcaplast Skim Coat Grey AP 100 .

• Avoid applying skim coat under direct sunlight; use a roof protector to protect areas that will be prepared.
• Add Mowilex Alcabond bonding agent to increase adhesiveness.
• Apply Alcaplast Skim Coat on the surface of the hairline crack with a width of 1 to 2 mm.
• After drying, sand until surface is smooth, then clean off leftover dust with a wet cloth.
• After the coat of Alcaplast AP 100 Skim Coat Grey has dried (after 7 days), apply a layer of Mowilex Undercoat Tembok before applying the topcoat.