Masonry Magazine October 2002 Page. 20
Cover STORY
Brick manufacturers also offer a wide variety of colors from which to choose. Color is determined by raw materials and firing temperatures. Colors range from reds and burgundies to whites and buffs, with many manufacturers producing more than 100 colors. Many of these color variations are created during the firing process when temperature variations and the order in which the units are stacked in the kiln determine shades of light and dark. Sand, slurry or ceramic glazes can be applied to the surface to achieve colors not possible with some types of clay.
There are endless possibilities when combining units of contrasting colors in bands or other patterns. Sample panels can aid in selecting the desired color by showing the finished appearance.
Choice of cleaning materials will be influenced by brick color. Acid cleaners can alter the color of lighter brick. Further, the presence of coatings requires an investigation into the cleaning technique and equipment to be used. For example, pressure washers can remove sand and some slurry, changing the look of the brick.
Another aesthetic feature to consider when selecting brick is the texture. Textures of brick can be smooth, wirecut (velour), stippled, bark, brushed and more. The texture interacts with light and creates differing and interesting shadows. Texture also has an influence on how easily the brickwork can be kept clean because mortar can fill the spaces in rough textured brick and make cleaning more difficult.
Unique design features can easily be achieved by using special brick shapes. Brick can be molded and formed into any shape, from simple sloped sill shapes to fancy water table brick.
"For most manufacturers, molded shapes are easier to produce than extruded shapes, because the molded, or soft-mud process is more adaptable to making brick shapes than the extruded process," comments Bryja. "However, making very large shapes can be difficult in either process because of problems with proper drying and firing."
Physical Properties
There are many physical properties, which may influence brick selection. Some of these include those influencing durability and
BEST PRACTICES: DO'S & DON'TS FOR BRICK SELECTION
Most brick construction projects are completed with the building owner, architect, contractor and brick supplier completely satisfied with the final product. To prevent misunderstandings which might result from improper ordering, sampling procedures, or ill-timed examination of field work, these "do's and don'ts" can help identify potential trouble spots and minimize their effects:
Don't Use Only Dollar Value Allowances: The practice of using only dollar value allowances for brick in construction specifications and/or contracts is not recommended. This method does not provide sufficient information to make an informed bid. If an allowance is used in a construction contract, the appropriate ASTM standard, grade and size should be stated. In the initial establishment of an allowance, the parties should take into consideration the extra cost of special shapes or units required by the project.
Do Use a Field Panel for Selection and Sampling: Since brick is subject to variations in color between production runs, and occasionally within the same run, small samples used for the preliminary selection may not exactly represent the complete range of colors and textures encountered in production runs.
When large quantities of brick are to be erected, the prudent owner, contractor, distributor or manufacturer should direct or request that the final selection be made from a field panel. A field panel is typically constructed as a freestanding sample, which will later be tom down when the project is complete. Usually, a quantity of brick equal to 100 standard-size brick will be used for building the field panel.
Figure 2: areas of the U.S. with differing weather conditions.
If an owner or the owner's representative requires the field panel, the distributor or manufacturer may not have control over the actual erection, which is frequently performed by a separate mason contractor. The party or parties who have control over the work of the mason contractor (either by direct contract or by other powers) will usually take appropriate action during the erection of the field panel to assure that no additions or deletions are made to the brick supplied by the distributor and manufacturer, unless written approval has been received from the manufacturer for such a change.
Field panels should be constructed from the production run that is intended for shipment to the project. In the event that the field panel has to be built for inspection and final selection before the production run for that project, the owner and the manufacturer should agree in writing upon such a use. The manufacturer may reserve the right to resample from the actual run before shipment commences. The owner or the owner's representative should inspect and approve the field panel.
When the field panel has been formally approved, it is the manufacturer's responsibility to provide brick as represented in that field panel. A strap or control sample is normally retained at the plant.
Typically, the general contractor and mason contractor are responsible for preserving and maintaining the integrity of the field panel which is considered the project standard for bond, mortar, workmanship and appearance, and as the standard for comparison until the masonry has been completed and accepted by the owner or the owner's representative. If the owner or his representative elects not to have a field panel erected, the parties may choose to use the first 100 square feet of actual construction as the field panel.