I think the advent of Atmos / Auro has led many to consider adding ceiling speakers.
As previously discussed (http://peteswrite.blogspot.sg/2014/12/adding-atmos-auro-speakers-to-existing.html), the ceiling can be a concrete one, and so there's cutting involved, or a false ceiling.
If it's the latter, then one must really ensure that the ceiling can bear the weight.
false ceilings in domestic settings were built by contractors to hold
the weight of some light fixtures, with cables inside and nothing much
more. They usually use aluminum struts the situation is worse if one has
a central false ceiling that is a single monolithic structure which is
lightweight and quite flimsy.
Eg, I got this from : http://renovationsingapore.sg/false-ceiling-singapore/
to add anything more than 3 kilos (multiplied by 4 speakers) will need
reinforcement or a complete tear down of the ceiling.
planning is needed before trying to add any speaker that one may already
posses. Otherwise during a serious session where the subwoofer is
employed and you may find the ceiling in your lap.