Why does the insulation layer fall off?

1. Base structure factors.

The outer wall of the frame structure is at the joint between the concrete beams and masonry. The insulation layer is easily damaged due to the deformation of the masonry. The scaffolding openings are not solid. The insulation layer is damaged due to the loose base. The exterior wall decorative components are not fixed firmly and shifted, forming a push-pull effect. The insulation layer is partially hollowed and cracked, and then water seeps for a long time, eventually causing the insulation layer to fall off.

2. Improper anti-pressure measures.

The surface load of the insulation board is too large. Or the negative wind pressure resistance measures are unreasonable. For example, the outer wall of coastal areas or high-rise buildings adopts a non-nail-bonded bonding method. It is very easy for the insulation board to be damaged by wind pressure and hollow and fall off.

3. Improper wall interface treatment.

Except for clay brick walls. Other walls should be treated with interface mortar before applying slurry insulation materials. Otherwise, it is easy to cause the insulation layer to hollow directly or the interface treatment material to fail. Forming hollows between the interface layer and the main wall. The insulation layer will also be hollowed out. The surface of the insulation board also needs to be treated with interface mortar. Otherwise, the insulation layer will also be partially hollowed out.

Why does the plastering layer crack?

1. Material factors.

The density of the insulation board for exterior wall insulation should be 18~22kg/m3. Some construction units will use insulation boards below 18kg/m3. Insufficient density can easily lead to cracking of the plastering mortar layer. The natural shrinkage time of the insulation board in the natural environment is as long as 60 days. Due to factors such as capital turnover and cost control of the production enterprise. The insulation board with an aging time of less than seven days has been put on the wall. The result is that the insulation board after the wall continues to shrink, and the plastering mortar layer adhered to the insulation board is cracked.

2. Construction technology.

The flatness of the base surface is too large. The use of adhesive thickness, multi-layer board, surface grinding and leveling adjustment methods will lead to defects in insulation quality. The dust, particles and other substances on the surface of the base that hinder adhesion have not been interface treated. The bonding area of the insulation board is too small, does not meet the specifications, and does not meet the quality requirements of the bonding area. When the rice mortar layer is constructed under the sun or in high temperature weather, the surface layer loses water too quickly, resulting in cracks.

3. Temperature difference changes.

The thermal conductivity of the two layers of materials, expanded polystyrene board and anti-crack mortar, is different. The thermal conductivity of expanded polystyrene board is 0.042W/(m·K). The thermal conductivity of anti-crack mortar is 0.93W/(m·K). The thermal conductivity difference is 22 times. When the sun shines directly on the surface of the plastering mortar in summer, the surface temperature of the plastering mortar can reach 50~70℃. In case of sudden rainfall, the temperature of the mortar surface will drop to about 15℃, and the temperature difference can reach 35~55℃. This temperature difference change and the influence of the temperature difference between day and night and the seasonal temperature lead to a large difference in the deformation of the plastering mortar layer, which is prone to cracks.
Landcel products for exterior wall insulation mortar: HPMC for EIFS, RDP