Brick Grade and Efflorescence in a Coastal Veneer
A coastal project specifies ASTM C216 Grade SW brick for an anchored brick veneer. The first delivery develops a white powdery deposit on the faces after a rain. The contractor proposes switching to Grade MW brick from the same plant because it is cheaper and available, arguing that the wall has a 1-in. air space and a rain screen. The region has a weathering index of 350 and moderate-to-heavy freezing. The submittal includes absorption results: 5-hour cold water absorption of 4.5% and saturation coefficient of 0.78. The mortar is Type N. The structural engineer has not reviewed the substitution. The inspector must decide whether to allow the MW brick and whether the delivered brick meets the specification.
1. Does the delivered brick meet Grade SW, and can the inspector approve the proposed Grade MW substitution?
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The delivered sample meets the Grade SW absorption limits on its face: 4.5% 5-hour absorption is well below the SW maximum, and a saturation coefficient of 0.78 is at the SW limit, so absorption alone does not require rejection. However, the white deposit must be evaluated; efflorescence can be a manufacturing or job-site condition, and ASTM C67 efflorescence testing may be required. The substitution to Grade MW is not the inspector's approval to make. Grade MW has less restrictive absorption and saturation limits and is intended for moderate weathering; with a weathering index of 350, MW might be technically arguable, but the approved documents specify SW and the EOR must evaluate durability, rain-screen detailing, and the actual exposure. The inspector should not approve the substitution orally or by field decision. Require a written EOR request, product data, and test results, and document the disposition.
2. What testing and documentation should the inspector require before accepting any of the brick?
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The inspector should require manufacturer certification and sampling per ASTM C67 for the delivered lot: 5-hour cold water absorption, saturation coefficient, compressive strength, and efflorescence. The tests should be from a qualified laboratory, with sample locations and lot identification. The inspector should also verify that the brick is not contaminated by salts or soil and that storage allows drainage and protects the brick from site water. If the white deposit is efflorescence, require the ASTM C67 efflorescence test and compare with the specification; do not simply wash the brick and accept it. The submittal should include the EOR's written acceptance of the source and grade, and the inspection record should tie the test results to the delivered pallets. Only then should the inspector allow the brick to be laid.