Hello,
Is quick lime, this volatile form of lime, something to be easily gotten from a commercial supplier?

Slaked lime, which is the end, or say, usable product, doesn't generate this sudden reaction and isn't precarious to work with at all, though not pleasant to breath in by any means. But this is what we're talking about in relation to plaster, right?

Historically I think the distinction wouldn't have been so relevant because the burned lime, - stone where that was around or seashells if that was nearby - would have been gathered and slaked and, left to brew, at a work site.

(This brewing aspect is also interesting in relation to plastering work. For masonry the slaked lime would have been left to brew for months ahead of the time it was used. Lime plaster for the finest work could be left in containers at the bottom of a well for as long as 40 years before it was used. That is called putkalk or well lime.)

I could buy this distinction between, let's say homes, and other buildings which were not lived in. But I don't know. Could it have anything to do with social or economic standing. That is, in expensive houses walls might be plastered with lime plaster and in simpler houses it was clay plaster. That's what I've seen around here so it's a question where one type of plastering was used or the other. Maybe it's geographical. What about in eastern Europe or the Southwest in the US? The way I like to look at it is that lime plaster is more refined and subtle and you can make a more exact surface than with these, let's say, rough clay plasters - not forgetting the fine tadelak work out of North Africa which is in fact combining clay and lime.

Anyway, that picture there above shows a variation in as far as it is a framework nailed onto the inside of the structural timbers, in this case the roof truss, with a lattice work - a reed mat in place of split lath - to form gaps for the plaster to latch onto. Pretty straightforward. It's clear that for a lot of history - or maybe not so far back really as just last week I sat in the kitchen of an old sheep farmer in France who's heavy timbered ceilings beams were wallpaper covered - timber, stone, brick were covered up with intention. Which I think says something about how important plastering in whatever form has been. But also how subject it is to fashion or trends.