Using a medium-bristle brush scrub the area with a solution of water and tri-sodium phosphate TSP or a non-phosphate detergent. Although cracks along the edges of. How To Repair Ceilings Before Painting Is Explained By Painters In Ottawa Pg Paint Design Prof Repair Ceilings Plaster Ceiling Repair Popcorn Ceiling Repair Thin straight hairline cracks at plasterboard joints andor exposed nail heads are signs. Cracks in plasterboard ceiling . Cracking between plasterboard panels is not however normally a serious problem. This movement causes cracks mostly at the location of the plasterboard joints. Not a quick remedy but a permanent one. Small cracks in ceiling plaster are normal and as weve just pointed out can happen when theres even a slight amount of natural building movement. Such cracks are most likely to appear when a side joint or end butt joint appear over or close to a framing variation extremity. Its normal for cracks to appear in plasterboard walls from time to tim...