Prepare mortar joints for repointing on historic masonry by removing deteriorated mortar to the correct depth without damaging the surrounding brick or stone edges

Steps

1. Consult NPS Preservation Brief 2 for joint-preparation guidance before starting demolition of existing mortar
2. Remove old mortar to a minimum depth of about 2 to 2.5 times the joint width (per Brief 2), which is typically deep enough to reach sound mortar and get a mechanical key for the new pointing
3. Prefer hand raking tools (chisels, church-key rakers) on narrow joints and softer masonry units to avoid widening joints or spalling brick arrises
4. If power tools are used, restrict grinders to cutting only the horizontal bed joints on hard, wide-joint masonry, and never let the wheel touch or overcut into the brick/stone faces
5. Flush all dust and debris from the raked joint with clean water and confirm the joint back and edges are sound (no hollow, crumbling mortar remaining) immediately before repointing
6. Inspect a sample area with the owner/preservation reviewer before proceeding to full-wall removal to confirm depth and technique are acceptable