Key Points for Quality Control in Gypsum Plastering

Created on 09.04

To ensure durability, smoothness, and crack resistance, gypsum plastering must be carried out with strict quality control. The main points include the following stages:

Worker applying gypsum plaster with tools, surrounded by plaster product options.

1. Substrate Preparation

Structural inspection & cleaning

: Confirm that structural works are fully completed. Remove dust, nails, and debris. Seal and repair wall penetrations, tie-rod holes, and pipe grooves.

Bonding agent application

: Spray a bonding agent evenly in a crisscross pattern with a nozzle distance of less than 30 cm, ensuring full coverage of corners and edges.

Anti-crack mesh installation

: Apply alkali-resistant fiberglass mesh at joints of different materials, pipe grooves, and stress concentration areas. Mesh width should be ≥25 cm. Apply a thin layer of gypsum plaster, embed the mesh, and cover again.

2. Control with Screeds and Markers

Reference line positioning

: Use laser or infrared tools to project vertical and horizontal reference lines as the basis for plaster thickness and alignment.

Setting plaster dots (gauges)

: Place plaster dots at wall corners and around openings, with thickness adjusted according to wall flatness and design (e.g., 15 mm). Ensure vertical alignment between upper and lower dots.

Screed strips installation

: Apply gypsum screeds between plaster dots at intervals of 1.5–3 m, ensuring continuous alignment from floor to ceiling. These strips serve as guides for uniform thickness and flatness.

3. Plastering Process

Mixing

: Stir gypsum plaster for 3–5 minutes until uniform. Use within 1 hour. Do not add water for remixing once it starts setting.

Thickness control

: Each layer should be 4–15 mm. Overly thin layers may cause powdering; overly thick layers may lead to cracking.

Leveling

: Use an aluminum straightedge or H-shaped ruler along screeds to scrape the surface. Vertical and flatness deviation should not exceed 4 mm (≤3 mm for fine finishes).

4. Curing and Acceptance

Environmental control

: Winter construction temperature ≥2℃. In summer, keep doors and windows closed to slow down evaporation. Continue with the next process only when surface moisture content is <10%.

Defect repair & acceptance

: Promptly repair hollows or cracks, clean the site, and carry out acceptance according to the Code for Acceptance of Construction Quality of Building Decoration Works.