I am building a reinforced brick masonry wall with a 2-inch collar joint. How long should I allow the masonry to cure before I place the grout?
If the wall is grouted too early, blowouts may occur. The length of time before grouting depends on how high the grout will be poured, the bond strength between the brick and the mortar, and any requirements of the governing building code. In its Technical Notes 17D, "High-lift Grouted Reinforced Brick Masonry," the Brick Institute of America (BIA) suggests that under ordinary circumstances the cure time should be at least 3 days. If the high-lift grouting method is used, follow recommendations for size and spacing of wall ties across the collar joint. Even masonry walls that have cured 3 to 7 days have had grout blowouts if not adequately tied to resist hydrostatic pressure.