Did some work out in the barn a little while back. The walls of the place had been a mess and were shedding sand everywhere. So I bought some Natural Hydraulic Lime, NHL3.5 with a couple of bags of sand and went nuts.
The workshop before. Can’t see it too well, but the wall in the back was a mess, a crack, a big hole, a couple of places where somebody had just slopped on a bunch of cement, 200 year-old mud/lime plaster coming off all over the place.
So I installed an insulated stud wall in OSB, over the one wall in ashlar-cut tuffeau stone to be able to heat the place next winter, and then got to work on patching and re-pointing the stone. I did one patch in 2 parts sand, 1 part lime, and a second in a 3-1 mix, just to see which looked better for when I do the wall in the attic room I am renovating. Chipping cement out, ramming mortar and bits of stone into the voids, piling in new tuffeau stone here and there to bring the wall back to flat.
For the rest of the room, I just patched here and there, knocked off any loose plaster, and then slathered on three or four coats of lime wash, working from very weak to almost a plaster. It really firms up the old plaster and mud/lime mortars. No more dust problems.
I’ll have to get a couple of real photos, but there it is in the background of this nifty new-to-me molding plane I was given a while back and needed to tune up.