Gypsum Plaster floors
Well…I thought it was concrete. but when I tried sanding with a sponge to keep the dust down, it acted like plaster…got a little muddy. So I looked online and found the attached, about gypsum plaster floors in England.
It appears that there is a mortar bed of about 1″ on the subfloor, and the plaster applied on top of that.
Anybody seen anything like that?