Tuck Pointing, Re-pointing, Patch Pointing, Stucco

We recommend leaving brick joints of good integrity alone as no better a bond can be achieved as that of the original joints.  The common practice of stucco application over good, sound brickwork is a real offense and should never be done. 

In re-pointing work, the joint should be removed 2-1/2 times deeper than the width of the joint.  A mason should only replace mortar that has eroded away 3/8” to ½” and sound joints should be left alone.  Patch Pointing, as it is known, should be done with as close a match to original joints as is attainable for appealing workmanship.

More important is the integrity of the mix of the tooling cement, however.  Historical bricks are almost always of the “fired” variety and the external shell that is provided by the process of heat curing protects the structure from moisture infiltration.  Moisture that enters a masonry structure and freezes during the winter causes a certain breakdown of the structure.  The original “shell” provided by the firing process should be protected and the mortar should be mixed to always be softer when cured as compared to the brick “shell.”  This softer joint material should be a sacrificial bond that will not become harder than the “shell” on the brick.    When a super hard mix that exceeds the hardness of the “shell” of the brick is employed on re-pointing work, subsequent breakdown of the “shell” of the brick will cause exposure to the soft interior of the brick.  When this occurs, the structure fails miserably.
Type ‘O’ is best for historical work.  The mix is similar to the following:

1 part Portland cement

2 parts hydrogenated lime and

9 parts sand (use river sand rather than builder's sand to obtain the proper color).

(By comparison, cement-lime-sand proportions of Type S is 2:1:9, Type N is 1:1:6, and Type K is 1:4:15.)

Portland Cement was first introduced in the 1870’s to quicken the cure time of the joints.   A mixture of mostly lime putty was used for joint work well into the 1930’s for brick joints. 

Pigments and various sands can be used to custom match existing mortar.  A week should pass for fully cured test mix to reach its final color.

Where joints are cracked or missing, a careful grinding of the horizontal joints to achieve the 3/8” minimum depth to connect two sections of joints may be done.  The brick should never be cut in this process as the “shell” will be damaged and the interior, softer portion of the brick will be exposed.  The best way to clean out the joints is by mechanical, hand chisel routing and cleaning of the joint.

If left alone to thrive, Vines are a formidable enemy of Brick Walls.