We conducted tension and shearing tests on lath and plaster ceiling in order to reveal the structural mechanism about the adhesion of plaster to wooden laths. In addition, we developed a mechanical model and a structural design formula for lath and plaster ceiling. Through the tests, it was found that whether plaster is pushed out to the rear of wooden laths or not, has the most important influence on the adhesion of plaster. We could develop the formula to accurately evaluate the strength of lath and plaster ceiling.
