What Is the Allowable Range of Flatness Deviation for GRC Exterior Walls? GRC Installation Precision Control Standards

The allowable deviation range for GRC exterior wall flatness, according to the requirements of the JGJ/T 322-2014 standard: panel surface flatness ≤3mm/2m, flatness at joints ≤1mm/2m, and overall facade verticality ≤H/1000 and ≤20mm. Strict flatness control is the key to ensuring the aesthetics and waterproofing performance of exterior walls.

Measurement methods: use a 2m straightedge and feeler gauge to check flatness, and a total station to check verticality. Through precise installation control, one project achieved flatness of ≤2mm/2m and joint straightness of ≤1mm/2m, with a clean and attractive facade. Installation error statistics show that 95% of measurement points meet the specification requirements.

Panel Surface Flatness Control

Mold precision ≤1mm/2m, installation adjustment allowance ±5mm. Large-area panels are fitted with stiffening ribs to control deformation to ≤L/500.

Joint Flatness Requirements

Height difference between adjacent panel surfaces ≤1mm, using a dedicated joint control system. Joint width deviation ≤1.5mm to ensure sealant application quality.

Facade Verticality Control

Establish a survey control network with control points set on each floor. Use a laser plumb instrument to control cumulative error.

Acceptance Standard Implementation

Acceptance is conducted in accordance with the GB 50210 specification, with a sampling ratio of no less than 5%. Professional instruments are used for measurement, ensuring objective and accurate data.

Flatness control requires whole-process management. From mold fabrication to installation adjustment, every step requires meticulous control.