Sulphate attack occurs most commonly in mortar, concrete foundations and floors, rising walls, flue liners, and chimneys. It is caused by soluble sulphate salts in some clay bricks reacting with constituents in portland cement, forming crystals that expand and cause cracking. Signs include lightening and cracking of mortar joints. Prevention methods include using sulphate-resisting cement and bricks with low salt levels, and keeping brickwork from becoming saturated. Sulphate attack is difficult to repair and often requires rebuilding. Proper inspection of moisture, soil chemistry, and structure is needed to identify the causes, which can include sulphate attack, wall tie failure, or salt erosion.
18. SULPHATE ATTACK? SALT EROSION? WALL TIE FAILURE? WHICH ONE?? Sulphate Attack? Wall Tie Failure? How do we know it isn’t all three causes? Salt Erosion?
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