What are the causes of cracking and hollowing in interior wall plastering mortar?
Release Time:
2015-07-30
Source:
What are the causes of cracking and hollowing in interior wall plastering mortar?
Interior wall Plastering mortar What are the causes of cracking and hollowing?
I. Material Factors:
1. Insulation board density is too low
2. Insufficient curing time for the insulation board
3. Chalking of the insulation board material
4. The thermal conductivity of the finishing mortar differs excessively from that of the insulation board.
5. Incompatibility or mismatch between the bonding material and the substrate results in poor adhesion of the insulation board, leading to cracking of the skim coat mortar layer.
6. Bonding materials with high bond strength, high strength, and significant shrinkage can also cause the insulation board to crack, leading to cracking of the skim coat mortar layer.
II. Construction Factors
1. Excessive unevenness on the base surface can be addressed by adjusting adhesive thickness, using multi-layer boards, or performing surface grinding and leveling; however, each of these methods may introduce quality defects in the thermal insulation system.
2. The substrate surface contains dust and other substances that impede adhesion, yet no interface treatment was performed prior to bonding.
3. The bonding area of the thermal insulation boards is too small, failing to meet the requirements of the relevant codes and construction plan, and thus not satisfying the quality standards for bonding area.
4. The embedment depth and number of anchoring nails for the thermal insulation boards do not comply with the requirements of the design and construction plan.
5. The overlap width of the alkali-resistant fiberglass mesh fabric does not meet code requirements, resulting in cracking at the lap joint.
6. The four corners of door and window openings are locations of stress concentration; when alkali-resistant fiberglass mesh is not applied in the 45° direction along these openings, cracks frequently occur.
7. When applying the finishing mortar layer under direct sunlight or in high-temperature conditions, insufficient water retention can lead to rapid moisture loss from the surface, resulting in cracking of the finishing mortar layer.
