<P> Lath and plaster is a building process used to finish mainly interior walls and ceilings in Canada and the United States until the late 1950s . After the 1950s, drywall began to replace the lath and plaster process in the United States . </P> <P> In the United Kingdom and its colonies, lath and plaster was often used for interior partition walls and the construction of ceilings, before the introduction of plasterboard in the 1930s . In the U.K., riven or split hardwood laths, of random lengths and sizes, were often used . Splitting the timber, as opposed to sawing in straight lines, followed the grain of the timber which greatly improved strength and durability . Also, reed mat was used as a lath . The technique derives historically from the earlier, more primitive, wattle and daub . </P> <Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2012) (Learn how and when to remove this template message) </Td> </Tr>

When did they stop using horsehair in plaster