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Animal Hair
Animal hair (usually horse, cow, goat or yak) is added to the
first two coats of lime mortar used for internal plastering onto stone, cob, brick or timber lath or external rendering.
Adding hair gives extra strength and minimises shrinking and cracking. It allows thicker coats to be applied to uneven
walls and holds the plaster keys in place when plastering onto lath. The animal hair is not introduced until about 24
hours prior to application as the alkaline in the lime attacks the protein in the hair and weakens the fibres compromising
its strength. The right consistency is demonstrated as a beard around the edge of a trowel full of mortar when inverted.
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