Going forward, put a generalized clause in your lease that prevents a tenant from disturbing the "quiet enjoyment" of the cohabitants of the building.

As I said, I can adjust the rents on the tenants to cover my extra costs without disturbing the relationship very much.

I read a disturbing article in the New York Times about people buying properties from online auction sites in areas that they know nothing about without doing any homework.

If they're disturbed, doped up, illiterate, the psychology/logic of most deterrents will be lost having no effect.

If it's easier to open up the back side common wall with out disturbing the shower surround do that before ceiling,under the leak, the water is coming from above and ceiling opening is just probably not going to  give you a clear point of where to start repair all the fittings and valves are up to high 

I can't imagine it's your fault that he removed the asbestos - get his boss to make sure it is disposed of correctly, make it clear in writing that you had understood it was not to be disturbed, and it shouldn't be a problem.

Having a room-mate in the house for the full 30 days, bringing guests, cooking, and doing whatever else people do during their day at home, would cause more chances to be disturbed whilst working.

leave the asbestos tile alone if it is still in good condition, it only becomes a problem when it's disturbed. 

Any further disturbances you are made aware of document and give notice for same. 

Too much risk of disturbing the current market and smart money (see Ackman on GSE: http://bit.ly/1lHRELJ ) is supporting this approach.Overall, despite the hoopla and rate mongering rates aren't gonna spike and fannie and freddie are dead: long live fannie and freddie.