![lath and plaster walls lath and plaster walls](https://www.indianalandmarks.org/wp-content/uploads/2016/06/lath-01-1024x724.jpg)
![lath and plaster walls lath and plaster walls](https://i.pinimg.com/originals/ea/fe/cc/eafecc2ec67f7623f8467378db406777.jpg)
As with lath and plaster walls, three layers were applied - the render, the floating and the setting layers. Where walls are brick, block or stone, the typical finish is plaster (see right). The use of lath and plaster was largely replaced by the use of pre-manufactured plasterboard when that became available in the mid twentieth century. These mixes were typically 1:1:6 (gypsum/cement:lime putty:sharp sand) for the first two layers and equal parts gypsum and lime putty for the setting layer. One disadvantage of using lime based layers was that each layer could take up to three weeks to dry before the next layer could be applied towards the end of the nineteenth century the practice developed to add gypsum or cement to the mixtures to decrease the time delay between each layer. The third layer was typically either lime putty on its own or a 3:1 lime putty to fine sand mixture. Traditionally the first and second layers were typically a 1:3 mixture of lime putty to clean, sharp sand often animal hair was also mixed in to help it bind together. The third and final layer (aka the setting layer) was about 3mm (1/8 inch) thick and was smoothed off to give a suitable finish for decorating.The second layer (aka the floating coating) was about 6mm (1/4 inch) thick and was applied to achieve a smooth surface for the thin, final layer.The first layer (aka the render layer) was about 8mm (3/8 inch) thick and was forced through the gaps between the laths to achieve a strong bond to the laths.The traditional method of coating lath and plaster walls was to apply three layers of lime putty mixture: The laths are the horizontal strips of wood (usually about 25mm by 6mm (1 by 1/4 inch) nailed to a vertical upright timber framework with about 6mm (1/4 inch) gap between each lath. Lath and plasterįrom the early eighteenth until the mid twentieth century, internal, non-load-bearing walls were usually covered using lath and plaster techniques (see right). Modern gypsum plasters are a lot harder and more brittle that the traditional lime putty used in older constructions. When repairing a plaster wall, the repair should ideally be carried out using the same materials as the original wall. Over the years, the practice of applying plaster to internal walls has changed quite a lot, the four basic forms found in post seventeenth century buildings are: