Plaster ceilings are traditionally made of lime plaster, which is applied in three coats, with animal hair mixed into the first two.
Caiff nenfydau plastr eu gwneud yn draddodiadol o blastr calch, a defnyddir tair haen o'r plastr calch hwn, gyda blew anifeiliaid wedi'i gymysgu i mewn i'r ddwy haen gyntaf.