Split laths, these can be either oak or chestnut are approximately 32mm x 9mm, and about 1220 mm long. We fix them to the oak frame with stainless steel nails. It is extremely important that a gap of 6-12 mm is left in between each lath. It is the mechanical grip of the plaster that is squeezed between the laths that holds it on – there is relatively little adhesion to the face of the timber laths themselves.