Noise problems are ubiquitous and are often difficult to handle. Let me suggest a few things, most of which apply only to co-ops. There's no Warranty of Habitability in a condo, which typically makes noise issues even more problematic.

You need to strike a good balance between doing too much and doing too little. In the case of your resident who hears noises in her walls that are within legally acceptable limits, I wouldn't do anything unless you have a simple and inexpensive solution you'd be willing to provide to anyone. And that's the problem: you *will* have to provide the same solution to any other shareholder who demands it. If you don't, you could be facing a lawsuit. "You did it for her, so you've gotta do it for me, too!"

If you're stuck with an existing policy you don't like, you may be able to draw a line in the sand and say, "From now on, we're not doing that anymore," but you need to be careful. Any exceptions must have very specific reasons behind them. No one is going to believe you're treating shareholders fairly if you keep erasing and re-drawing the line. "We did it for Ms. Jones, but never again! You can't have it, Mr. Smith! Oh, maybe we'll make an exception for Mr. Doe. And Ms. Chang. But that's the last time! Well, okay, Mr. Mackenzie. But you're the last one!"

If the noise falls outside legal limits and is attributable to another shareholder, then naturally you should bill any legal or engineering fees to that shareholder, along with whatever fines are allowable under your Proprietary Lease. If the illegal noise is the coop's responsibility, however, you need to be careful and prompt in fixing it. A classic example is River Terrace Apartments v. Robinson, in which the coop installed new and noisy machines in the laundry room. Robinson complained and the coop tried to reduce the noise and vibrations, to no avail. The board decided they'd done their due diligence, and that the rights of the many who liked the machines trumped the rights of the few.

WRONG, said the judge, awarding Robinson a 50% maintenance abatement. You can't violate one shareholder's Warranty of Habitability just because it benefits other shareholders. And due diligence has nothing to do with it: if the coop has failed to abate the problem, no one cares how hard they tried.

One of my good friends is living through a Robinson situation right now. Four years ago, his coop installed massive new washers that created a perpetual noise problem in his apartment. Making things even worse, the coop had installed the machines in a manner that flagrantly violated the manufacturer's instructions. After considerable back-and-forth -- during which the coop sent over an engineer and established there was a legitimate noise problem -- the coop installed the machines properly and put in some soundproofing. None of this helped significantly, and the board obstinately refused to remove the offending machines. The coop didn't even bother to send over an engineer after the work was done to see if the problem had been abated. This past month, my friend finally filed a lawsuit against his coop after exhausting every possible amicable solution.

In short, don't be cavalier about significant noise problems unless you want your building to become the next Robinson case. On the other hand, don't take wildly aggressive action against relatively trivial noise issues unless you want to get stuck doing a whole lot of work that isn't legally required.