Repointing is the process of renewing mortar joints in masonry. They can need renewing for various reasons, including:
1. Weathering causing the pointing to fail over the natural life of the mortar. This can often be only on exposed elevations of the building.
2. Incorrect mortar mix used during the initial construction process causing the mortar to prematurely age as seen in the slideshow to the left.
3. Poor repointing where either too strong or too weak a mix has been used.