Masonry Magazine August 2006 Page. 26
COLORED MORTAR
The lighter channels in each grouping show joints that were tooled before being thumbprint hard, bringing excess water and paste to the surface. Joints that are tooled in haste have a weaker surface paste that will come off over time. This could be compared to a concrete finished too quickly, which leaves a weak, thin surface that will pop off, or spall. In addition, joints that are struck in this manner often leave a drag mark from the jointer.
The darker channels were struck after the mortar set slightly too hard. When mortar joints are struck beyond the initial set, there is not enough water present to bring a paste to the joint surface, which results in the joint being slightly porous and dark.
QUALITY MASONRY TOOLS
KING BRICK HOD
Other Factors and Considerations
COLORED MORTARS are usually chosen from a reference colored mortar channel kit assembled by a pigment company. The owner or architect of the newly proposed building will usually choose a color to best compliment the masonry units on the job from one of these kits. The raw materials available to the mason contractor, be it field mix or factory pre-blended mortars, are (usually) not the same that the pigment company used when making the channels for their color kits. Also, pigment companies typically finish the joints in their color kits to expose a weathered look. Typically, the color channels will not have the same textured, tooled joint that will be used in the field.
For this reason - and prior to construction - a mock test panel should be erected using the raw materials and masonry units that will be used on the project. It is simply not good enough to pick colors from a pigment company's color kit and expect those colors to match the masonry wall exactly.
Cleaning Systems
For New and Restored Masonry
Owning your own Masonry Cleaning System means
YOU control work schedules and costs
YOU conrol your labor force activity
YOU control the finished look of YOUR project
YOU make more money
For more info go to www.kem-o-kleen.com
For a live demo call 1-800-274-4121
Building and Project owners demand excellence
Kem-O-Kleen
EXCELLENCE UNDER PRESSURE
If the walls are to be washed, the test panel should also be washed in the same manner as it will in construction. Prior to washing, the wall should be wetted down. If walls are not wetted, the masonry joints will absorb the cleaning agent and result in the etching or "burning" of the joint. In addition to leaving a dark appearance, it can leave the joint porous and subject to moisture penetration. For this reason, use cleaning solutions that are recommended for colored masonry and follow the manufacturer's guidelines.
As seen in the reference channels, the appearance of colored mortar can vary even when materials are measured precisely. After the desired colored mortar is chosen, erect a test panel prior to construction to ensure that the owner, architect and masons are all on the same page prior to construction. As evidenced through out this article, water demand will vary throughout the course of a project, so always tool mortar joints when mortar has a uniform hardness-when joints are thumbprint hard.