Avoid using water or water-based chemicals in freezing conditions. Repointing Disintegrating mortar, cracks in mortar joints, loose bricks, or damaged plaster work may signal the need for repair of masonry. Remove deteriorated mortar by carefully hand raking the joints to avoid damaging the masonry. Do not remove mortar with electric saws or hammers that damage the surrounding masonry. Duplicate mortar in strength, composition, color, and texture.
Brick expands and contracts with freezing and heating conditions.
When this change occurs, old mortar moves to relieve the stress. If only portland cement is used, the mortar does not flex as much and the brick can crack, break, or spall. Do not repoint with a synthetic caulking compound. Mortar of older brick buildings has a high lime and sand content. In newer buildings the lime content would be decreased and the portland cement content increased.