Are there hollows and cracks in the plaster?

1. Oily release agent is used for formwork demoulding, and the concrete surface is too smooth. Poor adhesion causes hollowing and cracking of the plaster surface.

Cause analysis:
Oil or solvent-based release agent is used on the wooden formwork surface. The plaster surface is too smooth or oil residue remains on the surface. Poor adhesion causes hollowing and cracking of the plaster surface.
Improvement:
Water-based release agent should be used for demoulding of non-clear water concrete. Control the demoulding time. That is, to ensure the quality of concrete molding. And to ensure the adhesion of concrete. Reduce the risk of hollowing and cracking in the later stage.

2. The masonry assembly and construction method are unreasonable. Masonry settlement causes hollowing/cracking of the plaster surface.

Cause analysis:
The inclined top bricks are not densely assembled, and the inclined top angle is too large. The inclined top of the long wall is assembled in the same direction, and this part is prone to cracking in the later stage.
Improvement:
The inclined top bricks should be assembled densely, and the angle should be 45-60 degrees. When the wall is long, it should be built in two directions with an inverted eight-shaped masonry, and the middle part should be placed with finished triangular blocks.

3. The mesh is not hung at the junction of different materials. Or the mesh hanging method is unreasonable, resulting in cracks.

Cause analysis:
The mesh is not hung at the junction of different materials. The galvanized mesh is directly pasted with cement mortar, and the galvanized mesh is arched and has insufficient crack resistance.
Improvement method:
Concrete and sintered bricks use insulation nails to fix the galvanized mesh, and sand aeration is fixed with cement nails. When fixed, the galvanized mesh is flat and does not arch.

4. The grooved surface of multiple pipelines is not blocked or the blocking method is unreasonable, resulting in cracks on the plastered surface.

Cause analysis:
The groove depth of the wire pipe is insufficient. After the wire pipe is fixed, it exceeds the masonry surface. This is a weak part of the plastered surface, which is easy to cause cracks in this part.
Improvement method:
Strictly control the groove depth of the wire pipe, dn+10mm≤groove depth≤dn+20mm, groove width dn+20mm≤groove width≤dn+60mm. Avoid damaging the wall by cutting too deep grooves, and avoid making the grooves too small to seal tightly.

5. The concrete and autoclaved masonry are not sprayed before plastering or the spraying adhesion is poor.

Cause analysis:
The concrete spraying is not full enough, the strength is poor, there is a lot of spraying peeling, which reduces the adhesion and easily leads to cracks in the plastering.
Improvement method:
Spray the concrete spraying fully to improve the adhesion of the spraying.