We live in a 150-year-old limestone villa. It has many charms, but one of its downsides is the constantly-decaying walls and ceilings. Simply put, they’re slowly falling apart.
The effect is most pronounced along the edges of the walls (see the above photo) and in rooms below rooms in which we’re active. For example, our office is above our living room. The coffee table is constantly being showered with little bits of the ceiling.
We need to constantly sweep. The photo shows a section of wall after two or three days without attention. This morning I swept the bottom floor of the house–the kitchen, dining room and living room. I’m not exaggerating when I say I discarded at least two cups of limestone dust. Another 100 years, and the walls will be half as thick as they are today.
DarrenBarefoot.com 
There must be some way to bond the walls to stop this? All that dust cant be too healthy?