Masonry Magazine April 1977 Page. 13
light pink color of the salmon creates the desired effect. Unfortunately, the pink in salmons results from under-burning which produces units that must not be exposed to weathering. Excessive disintegration due to weathering can soon drastically alter the appearance originally sought.
All pink brick are not necessarily under-burned. During recent years the architectural demand for a variety in colors has led to the extensive use of raw clays which burn other than dark red when fired to maturity. Today, among other colors, many hard-burned, pink brick are available. These units may conform to the requirements for highest quality under applicable ASTM specifications.
FIG. 4
Because of the greater likelihood that moisture will be present, salvaged brick should not be used for exterior patios, walks, pavements, etc.
Many manufacturers blend different colored brick to provide a rustic appearance similar to salvaged brick. There are advantages to using new brick: the architect may specify any desired color proportions and may specify the desired grade under ASTM specifications. Thus, he can obtain the desired esthetic effect without sacrificing durability or strength, a feat which is nearly impossible to accomplish when using salvaged brick.
That is, many pink brick conform to grades SW or MW (severe or moderate weathering) under ASTM C 216 or C 62.
Economics. Although in many instances salvaged brick have sold for more money than new brick, a principal reason for their use is their low prevailing initial cost. But initial economy often proves to be false economy. For example, labor costs are usually higher for salvaged brick.
The ultimate cost reflects a true comparison of values. Using the present worth method of analysis it can easily be shown that an initial cost saving of $30 per thousand brick may be offset by a maintenance cost of only cent per sq ft per yr. Maintenance costs for salvaged-brick masonry are very likely to exceed this amount considering: (1) cutting out and replacing disintegrated units; (2) tuck pointing mortar joints to reduce leaks and repair cracks; and (3) repeated attempts at waterproofing. In many cases, the initial economies of salvaged brick prove false and result in higher total expenditures.
BUILDING CODE REQUIREMENTS
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American Standard Building Code Requirements for Masonry, ASA A41.1, Section 2.1.1 (appendix commentary):
"Second-Hand Materials. Irrespective of the original grading of masonry units, compliance with code requirements of material which has been exposed to weather for a term of years cannot be assumed in the absence of test. Much salvaged brick comes from the demolition of old buildings constructed of solid brick masonry in which hard-burned bricks were used on the exterior and salmon brick as back-up, and since the color differences which guided the original brick masons in their sorting and selecting of bricks become obscured with exposure and contact with mortar, there is a definite danger that these salmon bricks may be used for exterior exposure with consequent rapid and excessive disintegration. Before permitting their use, the building official should satisfy himself that second-hand materials are suitable for the proposed location and conditions of use. The use of masonry units salvaged from chimneys is not recommended, since such units may be impregnated with oils or tarry material."
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Southern Standard Building Code, Section 1401 General:
"Masonry units may be re-used when clean, whole and conforming to the other requirements of this chapter, except that the allowable working stresses shall be 50 per cent of that [sic] permitted for new masonry units."
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National Building Code, Section 909.2. (i) Construction:
"Under-burned clay brick shall not be used in any part of a a building or structure where exposed to the weather, nor in isolated piers, nor in such part of a bearing wall above which the wall extends more than 40 feet."
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Uniform Building Code, Section 2403 (w) Re-use of Masonry Units:
"Masonry units (made from clay or shale) may be re-used when cleaned, whole, and conforming to the other requirements of this chapter."
For further information on this cost analysis method, see Ultimate Cost of Building Walle, SCPI, 1960
The dangers in coating masonry of under-burned units are discussed In Technical Notes No. 7, "Dampproofing and Waterproofing Masonry Wals Under-burned units may undergo accelerated disintegration if coated with impermeable paints.
See references.