The Perils of Lath and Plaster Ceilings
21/12/2013 · Plaster is brittle by nature and will crack at its weakest point under vibration. In practice that means the nibs that wrap around the laths and keep the ceiling in place snap off. If enough of them snap off the weight cannot be supported and the ceiling collapses. Similarly, water from above soaks into the porous plaster and weakens the nibs. Some onlookers at the .