Why Does the Steel Skeleton Light Plate Break?

Steel frame lightweight panelForming the base layer of the roof, combining flexible waterproofing, why does the steel frame lightweight panel crack? We will delve into this in detail for you next.

1. Material factors. The density of the external thermal insulation board should be between 18~22 kg/m³. Some construction units may use substandard materials, opting for insulation boards with a density below 18 kg/m³. This insufficient density can lead to wall cracking. The natural shrinkage time for thermal insulation boards in a natural environment is as long as 60 days. However, due to factors such as production enterprises' capital turnover and cost control, the aging time is less than 7 days. As a result, the thermal insulation boards are already installed on the walls, causing the external thermal insulation boards to continue shrinking after installation. This leads to the insulation layer adhered to the additional thermal insulation board being pulled apart.

2. Construction Technology. Due to excessive flatness on the base layer surface, adjustments using adhesive thickness, multi-layer panels, and surface grinding for leveling can easily lead to quality issues with insulation. Additionally, because the base layer surface's dust, particles, and other substances hindering adhesion have not been treated, the bonding area of the insulation panels is too small, failing to meet specifications and resulting in inadequate insulation coverage. Constructing the surface mortar layer under intense sunlight or high temperatures causes the surface layer to lose moisture too quickly, leading to cracking.

3. Temperature difference variations. The thermal conductivity of expanded polystyrene board and anti-cracking mortar layers is different, with a thermal conductivity of 0.042 W/(m·K) for the expanded polystyrene board and 0.93 W/(m·K) for the anti-cracking mortar. This difference is 22 times greater. When direct sunlight hits the surface of the coating mortar during summer, the temperature can reach 50~70℃, and in the event of sudden rain, the temperature can drop to around 15℃, resulting in a temperature difference of 35~55℃. Such temperature variations, along with diurnal and seasonal temperature fluctuations, can cause variations in the thickness of the coating layer and lead to cracking.