Causes of Wall Cracks and How to Repair Them Using a Putty Knife

　　First, let's explore the several causes of wall cracks:

　　1. Cracks appearing at the joints between wall insulation boards;

　　2. Shrinkage cracks appearing in the wall grooves and cable channels where filler was applied;

　　3. Stress cracks caused by uneven application of plaster and putty.

　　Several methods for treating wall cracks with putty knives:

　　1. Method for treating cracks in insulated wall panels: Use a putty knife to carefully cut open the cracks—aim for as deep an incision as possible—and fill them thoroughly with gypsum plaster, ensuring the material is evenly applied and tightly packed. Once the filler has dried, reinforce the cracked area by applying bandages, muslin cloth, or fine white cotton fabric. After drying again, proceed with spackling or other finishing techniques. If the cracks are particularly severe, you can also use kraft paper or newspaper to patch the gaps; this method may provide even better results.

　　2. The reason for wall cracks appearing after filling cable channels with putty is that the drying speed and shrinkage rate of the cement mortar differ from those of the putty powder. By the time the putty on the wall surface has fully dried, the cement mortar inside remains partially wet, leading to cracking. For treating wall cracks, using gypsum powder to fill the cable channels tends to yield better results.

　　3. Cracks can also appear if the wall putty is applied too thickly in one go, or if there’s an excessive variation in thickness across the entire wall—leading to severe cases where the material may even start to peel off. Wall crack treatment method: If necessary, apply multiple thin coats instead of a single thick one, allowing ample drying time between each layer. However, keep in mind that applying too many layers of putty can increase the risk of it eventually coming loose.