Greetings,

I am very much an amateur in the art of fresco, having jumped into it headfirst last summer when I plastered our entire basement armed with no more knowledge than I could gather from combing the internet (ah, if only these forums had been around then!) Now I am moving up in the world - I am now plastering and frescoing the front staircase of our house.

Now, this house was built in 1779, and has settled a bit since. This results in the plaster along the staircase wall buckling in places - picking up giant cracks and pulling away from the wall. It looks as if it has been replastered once since the colonial era, but what I think may be the original plaster is still visible underneath. It's a sort of tan-brown,quite rough, with what appear to be hairs mixed in it. Maybe there was also a top coat, too - there appears to me more than one layer in the chips that have pulled away.

And now for my questions! Does anyone know anything about the sorts of plaster that would have been used in colonial America (the Connecticut River valley region, if you want specifics). Would they be suitable for fresco?
What steps ought to be taken to restore the wall?

I found an old Essex County recipe for a lime finish designed for whitewash, which included rice flour and common glue besides the lime and hot water. The book in which I found it (American Decorative Wall Painting 1700-1850) when speaking of fresco itself, says, tantalisingly, that "directions for this process are found in many of the old English recipe books, but this method does not seem to have been used by the itinerant decorators whose work we are considering." And that's all it says about fresco. Does anyone know what those directions might have been, or if they differed substantially from the ones available today?

Also another question, not really relating to the colonial era: last year, when I was experimenting with fresco in the basement, I tried something called "autoclaved finish lime". It said to use immediately if mixing by machine, and I did. The paint went onto it very nicely, but later the plaster began to crack. Not too seriously, fortunately - indeed, now the fresco has the antique look that has been sought with so much labor by other painters. But I was wondering - what does "autoclaved" mean, and is it really suitable for fresco, and if so, what are the proper preparation steps? On the back of the package it said to mix with gauging plaster, but I do not think that the instuctions were directed towards one who wishes to create a fresco. I've never heard gauging plaster mentioned in all my reading on the subject of fresco plastering; what is it?

Thanks for the wonderful forum,

Katherine Nehring