What causes failures in tilt-up panel joints?
There can be several causes: dirty or chalky concrete surfaces at the time of sealing; presence of form release agent on the concrete when the sealent is applied; poor choice of sealant; too small a joint width for the depth; poor workmanship. One of the factors frequently overlooked is the ratio of the joint width to the depth. For panels up to 15 feet wide the joint should be at least 1/2 inch wide and for wider panels at least 5/8 inch wide. Furthermore, a backup rod of cellular rubber or other compressible material should be used behind the sealant so that the cross section of the sealant will be approximately square.