What should be done before replacing damaged CMU?

Before replacing damaged Concrete Masonry Units (CMU), it is essential to remove all mortar using appropriate tools to ensure a clean and stable surface for the new unit. This process is crucial because when you remove the damaged CMU, any leftover mortar can impede the proper fit and adhesion of the new block. A clean surface allows for better bonding with the new mortar that will secure the replacement CMU in place.

After properly removing the mortar, one can assess the surrounding integrity and prepare the site for the new CMU. This removal process helps ensure that the new masonry unit will be set accurately and securely, which is critical in maintaining the structural integrity of the entire wall. Without this step, you risk issues such as improper alignment or inadequate strength, which can lead to future problems in the masonry structure.

It's also important to note that methods like soaking the damaged CMU and applying a new layer of mortar are not suitable as they do not address the underlying issue of the damaged unit or properly prepare the site for replacement. Assessing the structural integrity of the surrounding bricks, while an important step in masonry work, typically follows the removal of the damaged unit rather than preceding it.