sound-reducing outdoor floor covering?

I would assume pavers installed on pedestals would work but I am guessing

Astro-turf.

But I'm just guessing.

You plan on gettin' freaky out there, bramstar?

Ballards sells outdoor rugs, or you could go with fake grass, or you could have a floating deck. It depends how much money you want to spend.

Thanks for the input--we'll look into the pavers-on-pedestal and floating deck ideas... astroturf isn't a bad thought either.
Truth, LOL, it's not for me, it's for some kids who love to ride their scooters on the roof :-)

@Bramstar....best solution is buy the roof rights from the builind and put in stairwell from your apartment up. even if you just buy the portion directly above you it will help + improve your resale rights.....

Dean--if only!! But alas, they belong to someone else...

pavers and floating decks will not accomodate scooters and the like well

ab, not sure why you say that.

Take a look at http://www.bisonip.com/ for Bison deck tiles, which are used in all kinds of commercial settings and have no problem standing up to use/abuse.

However, I'm still not sure how much sound/vibration will be absorbed by any of the above ideas, since they all rest on the roof that's there right now. Short of laying steel I-beams atop the building's parapets and building a deck on the beams, which will truly isolate the deck from the roof, I wouldn't expect much difference in what the top floor tenants hear.

I had a similar unimproved roof terrace to deal with, but wasn't concerned about the noise below. Ended up building four-foot square decking sections, resting them atop rubber-wrapped blocks, and bolting the sections together. They're easy to remove for maintenance (just unbolt and carry away) and a lot cheaper than Bison.

What's the weight load of the roof? Is it unimproved for a reason? My building has two top floor apartments (mine being one of them). It was no problem for the front neighbors to build a roof deck with the existing 40 lb. per square foot weight load in 1990. When we went to do the same thing in 2010, the city required we reinforce to 100 lb. per square foot, necessitating a steel beam and all kinds of other crazy, expensive work before we could legally put down any type of covering.

If you don't know the weight load, I wouldn't put down a pedestal system. They are heavy. Also expensive. I think the cost of a good-quality system for my 250 square foot roof terrace was in the neighborhood of $12k-$15k uninstalled.

Not sure if this can be installed in a way that makes sense for your situation but...
http://www.quietrock.com/soundproof-products/soundproof-wood.html