Q: When building a cinderblock wall, should I fill the voids in the blocks with mortar?
A: We recommend filling the empty spaces of the blocks with sand topping mix or core-fill grout to ensure a solid core and strong wall. Increase the wall’s vertical strength by inserting sections metal rebar into the filled voids to connect the blocks from course to course. You can also add horizontal reinforcement by setting ladder shaped metal reinforcement grids into the mortar beds of every third course. Overlap the ends of the metal grids by about 6 inches.