Chimney Repointing is the process of carefully removing deteriorated mortar from the joints of a masonry wall and replacing it with new mortar that has been intelligently formulated.
If done well, repointing will both protect the building and enhance its historical character. Improperly done, repointing not only detracts from the appearance of the wall, but may cause damage to the historic masonry units themselves.
To repoint a chimney correctly it requires all mortar joints to be ground out to a least a 1.5? deep. It is important to have a deep anchor of the new mortar to bond. This also offers longevity to the repointing. Once that is completed, we begin repointing the brickwork of the chimney.
Next, we apply the lime-based mortar filling to all mortar joints, which seals all air pockets and voids between the bricks.
It also adds back some of its structural strength. This is to ensure that the new mortar bonds to the brickwork. If not done properly, the repointing will fall out in a few years from the lack of bonding.
After all the joints are filled and sit for about an hour we strike all of the mortar joints to achieve the finished look.
Last, we smooth out the new mortar and make it flush with the brickwork. We use a wooden stick similar to those used in the construction of historical homes. After smoothing out the mortar, we wash the chimney in an acid washed and everything is cleaned up.
The bottom photo is of a completely repointed chimney.
Chimney that has been repointed.