Squeaky floor boards - access only from above

I'm in a 6th floor condo with no access below. There is a high traffic area which is basically to hub to get anywhere, and over time has developed some squeaky floor boards. The flooring is solid hardwood. I've read mixed reviews on Squeeeek No More screws - though mostly positive. I would imagine a good amount of the negatives are some mix of misuse/wrong application.

But even so I was thinking if there's a way I could test if the Squeeek No Mores would be helpful in advance, before creating a bunch of screw holes. I used a stud finder with deep scan to locate the joists. I believe I have them as the finder picks up solid hits every 16 inches. Next I walked around and found that the squeaks are consistent in a roughly 3' by 5' area and primarily running along 2 joists.

So my first thought was to place heavy objects along the 2 joists to somewhat simulate new screws binding the subfloor to the joists. I don't have a lot weights hanging around anymore. Only have about 100LB of free weights, maybe 30-40LB of books, and a few gallon jugs of water.

But after toying around with the placement of items, and walking over the boards it didn't seem to make any difference; at all. I wasn't expecting the noise to go away completely but was hoping for some notable change whether it be quieting a small section that used to be noisy or dampening the squeaks by a little bit.

It may just be the weight is not sufficient to make a difference. Before I get to crazy and start wheeling out furniture for testing, wanted to get people's thoughts on this. Does my plan sound viable at all? If so what would you suggest; placing all the weight along a single joist; or trying to clamp down a small section by stacking the items along both joists for a shorter stretch?

 

I would expect a 6 story condo to have concrete floors. If wood sleepere have been laid over it, its anyone's guess as to how and why its squeaking, but there would likely be no easy solution if its over concrete.

 

It's an older building that was renovated maybe 20 years ago; not sure on building code but I suppose it would be grandfathered in if such a code existed. In any case assume it's not concrete - I'm sure it's no due to the soundproofing (or lack thereof).

 

Don't think amy thing you put on the floor will be heavy enough. All you can do is try to screw it down anywhere it squeeks and see if it helps.