ᐅ Built in 1954 – What Type of Plaster Do I Have and How Can I Preserve It?

Hello everyone,

I have purchased my parents’ house and would like to know what type of plaster is currently applied. I hope this can be identified from the pictures. According to a plasterer, it is lime/sand plaster. However, there is a thin layer of paint over it from that time. The questions I have now are:

• If it is lime plaster, I want to preserve its beneficial properties, but I need to repair and level some areas and then apply painter’s fleece. Is this possible? Which type of filler should be used for this?
• Does the existing paint layer interfere with the properties of the lime plaster?

I have received a quote: The process would involve applying a base reinforcement layer first, then applying filler directly onto the fleece, without sanding, similar to filling over painter’s fleece. Would the filler or the fiberglass fleece hinder the lime plaster?

Since I have recently replaced the windows with ones rated below 1 U-value, I would prefer to avoid the sealed, “new build” feel—in other words, the plaster should continue to act as a humidity regulator.

Thanks in advance!