CSLB C-33 Painting & DecoratingSurface PreparationEasy
A painting contractor is preparing an interior plaster wall that has several hairline cracks. The cracks are stable and do not show signs of movement. What is the most appropriate repair material for these types of cracks before painting?
- AFiberglass mesh tape embedded in joint compound.
- BAcrylic latex caulk or spackling compound.
- CCementitious patching compound.
- DEpoxy injection.
Show answer & explanationAnswer & explanation
Correct answer: B. Acrylic latex caulk or spackling compound.
For stable hairline cracks in plaster, acrylic latex caulk or a good quality spackling compound is sufficient. These materials offer flexibility and good adhesion, effectively filling the cracks without requiring extensive work. Epoxy is for structural cracks, mesh tape for larger drywall cracks, and cementitious compounds are for concrete/masonry.
Why the other options are wrong
- A. Fiberglass mesh tape embedded in joint compound is primarily used for drywall seams and larger cracks, not fine hairline plaster cracks.
- C. Cementitious patching compound is designed for concrete or masonry surfaces, not interior plaster walls.
- D. Epoxy injection is typically used for structural cracks in concrete or masonry, not hairline plaster cracks.
Hairline Crack Repair (Plaster)
Stable hairline cracks in plaster are best repaired with flexible, fine-grained fillers like acrylic latex caulk or spackling compound to ensure a smooth, durable finish.
- Material choice depends on crack size and stability.
- Flexibility is key for minor plaster cracks.
- Avoid rigid fillers for hairline cracks.
Memory trick: Cracks call for Caulk, not Concrete or Complex compounds.