Check your building’s by-laws for specifics. Our building has very detailed and prescriptive rules (including 11mm Regupol dense foam insulation). I didn’t agree that the by-law should be so prescriptive – better technology could come along before the ink on the by-laws was dry – but we went along with it anyway. There have been no complaints so far (about 9 months) so I’m happy.
In the absence of a by-law – and even when there is one – the only thing that matters is whether or not the noise will transmit to the units below and adjacent. When we were looking for our timber floors I was offered all sorts of magic solutions and had flooring salesmen telling me that the by-laws didn’t count because “boring old farts” on EC committees would be over-ruled by the courts.
Needless to say, we went elsewhere (Precision Flooring) to be precise and even though they were expensive, they did a great job. You may find someone who will do the job more cheaply and just as well but I would be looking for a guarantee that they would replace the floor and insulation free of charge if the EC received valid complaints that there was too much nois.
Nothing quite works quite as well as properly insulated carpet but there are some flooring systems that do the job adequately.