Description
Sawn larch laths are supplied in bundles containing 4′ (1.22m) lengths. They are used to build traditional lath and plaster walls, they can also be used to replace laths in damaged areas of an old wall.
The laths are cut from straight grained timber producing longer, stronger units. Sawn laths have the added benefit of being both easier and faster to fix than their riven counterparts thanks to their machined, uniform length and profile.
Timber laths are an ideal background for lime plaster, they provide a good key and form a gauge that keeps the plaster relatively even. They also help prevent shrinkage cracking when applied correctly.
The laths are fixed horizontally to the wall or studs, typically with 10mm spacing between them. The gaps between must not exceed twice the largest particle size in the plaster base coat.
Timber laths must be completely saturated when fixed, they will shrink and pull tight as they dry out. This requires the lengths are fully immersed in water for at least 7 days (although longer is better) up until the point of fixing.
The laths must be soaked through again (typically with a nap sack sprayer) 2 hours before plastering work proceeds. Plastering onto wet laths helps prevent cracking, otherwise, dry timber would suck the moisture rapidly from the lime plaster as it is applied.
As the laths were saturated initially when fixed, they simply expand back to their original position rather than buckling and failing as is common when laths are fixed dry.
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