Jonathan Frame wrote:I wonder how horse manure differs from cow, is it more adhesive and binds with sand and clay better?
Dan Chiras wrote:Cow dung can be added to earthen plaster, but horse manure is generally better. That said, I don't think manure is going to make the plaster any more resistant to rain, especially driving rains. I see from the photos that there is considerable erosion of the earthen plaster. I would recommend a finish coat of lime-sand plaster. We describe this technique in our book, The Natural Plaster Book. Lime-sand plaster turns to limestone over time and makes a really weather proof exterior plaster.
Jay C. White Cloud wrote: The "pectin" active ingredient in cactus juice) can also enhance lime finishes as well.
Whey is common additive, yet I am not fond of it as the proteins in it can contribute to mold. Casein however is a primary ingredient in many traditional finishes that are often augmented with lime (think "milk paint".)