Dictionary of Moisture Protection & Restoration

G.S.U. = Glazed Structural Unit. Gunite = A proprietary name for shotcrete. Hairline cracks =

Very fine cracks, in a random pattern which usually do not completely penetrate an exposed layer of concrete. Also called shrinkage cracks (when caused by shrinkage). Hairline joint = A joint not more than 1/64 in. (0.38 mm) wide. Hair mortar = A mortar containing cow’s hair, lime and sand. Half bat, half brick, snap header = A brick cut to half its length. Hard to the line = Masonry unit set too close to the guide line. Harsh mortar = Mortar that is difficult to spread. Hawk = A small mortar board. Header = A masonry unit laid flat on its bed surface with end facing out; also used to tie two wythes together. Headway = Clear space under an arch.

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