Common Plastering Mistakes to Avoid: Civil Engineer Shares 6 Tips to Prevent Wall and Ceiling Cracks

Cracks appearing on walls or ceilings shortly after construction can spoil the beauty of a home and raise concerns about dampness and structural integrity. According to civil engineers, these cracks are often the result of small mistakes made during plastering. Here are six essential tips to ensure long-lasting, crack-free plaster.

1. Sift and Use Quality Sand

Sand plays a crucial role in plastering. Always sift the sand before use to remove stones, debris, and dirt. Fine sand is ideal; coarse sand or sand with high clay content increases the risk of hairline cracks once the plaster dries.

2. Use Fiber Mesh or “Murga Jali”

Cracks often appear where brick walls meet concrete columns. Applying fiber mesh or murga jali at these joints strengthens the bond between different materials. The same technique applies to areas cut for electrical pipes: cover the pipe joint with mesh before plastering.

3. Hacking the Surface

Concrete surfaces are very smooth, making it difficult for cement mortar to adhere. Hacking—creating small holes or roughening the surface—ensures the plaster sticks properly. This is especially important for smooth ceilings or surfaces with foil layers.

4. Pre-Wet Surfaces and Use Thick Mortar

Walls and ceilings should be thoroughly dampened with water a day before plastering and also on the day of work. Apply a thick cement-water slurry as a bonding layer between the old surface and new plaster. This prevents detachment or hollow sounds in the future.

5. Maintain Correct Cement-to-Sand Ratio and Thickness

The ideal cement-to-sand ratio is 1:4 or 1:5, meaning one part cement to four or five parts sand. Interior plaster thickness should be between 10mm and 12mm. Excessively thick plaster may crack or fall under its own weight.

6. Ensure Uniform Finishing

Plaster should be applied evenly across the wall or ceiling without gaps. Consistent leveling ensures smooth finishing, making putty and paint application easier and more economical. Uneven plaster not only looks unattractive but also increases paint consumption.

By following these expert tips during plastering, homeowners can prevent future cracks, enhance durability, and achieve a flawless paint finish.