Would be grateful of any advise about this. I live in a 1930's house and earlier in the year a 2ft section of the soffit fell away. On inspection I find that the soffit is made of wooden lathe covered with 2 layers. The wooden lathes are sound and it's just the plaster and mortar layers that have fallen off. The first layer (closest to the wooden lathes) appears to be of course plaster with horse hair. The second layer (the exposed finish) appears to be mortar render.
Would be grateful of any advice on how to repair this using modern materials. The rest of the soffits are sound and I don't intend to replace with upvc or smooth superboard.
Does anyone know of a modern plaster that I can use as a substitute for the original horsehair plaster as the first layer ?