Most old buildings in San Francisco are built of wood (even if there is stucco or other siding), and sound transmission can be intense. You can pay a million and a half for a condo and still hear every footfall or shriek from the teenager or toddler upstairs. Or you could have these horrible neighbors upstairs (heaven forbid). This is why many condo associations require 75% carpet over hardwood.
Concrete buildings are much quieter so they are a good choice if you are especially sensitive to sound or a very light sleeper. These quieter buildings are primarily newer construction, or sometimes older industrial conversions. Typically they are larger concrete buildings in more urban neighborhoods. An added bonus is that these buildings are more likely have access to Internet alternatives to Comcast or AT&T, such as MegaPath or Monkeybrains.
If you prefer the older San Francisco architecture, or smaller buildings, or you are already in a neighborhood that is mostly older construction, you may have to navigate noise issues with your neighbors. Tread carefully here. I have seen drama over noise escalate between neighbors, create a lot of stress, and reduce property value more than 15%.
Saving money by not doing sound reduction ended up being expensive for my clients who eventually chose to sell their home to feel peace in their lives. They did the right thing and disclosed the sound conflicts, there by also avoiding lawsuits, but the buyer got a really good deal because not everyone wants to move into the middle unit of a 3 unit building with a history of acrimony over sound.
Total “sound proofing” is not really possible in these old wood buildings, but you can definitely take the edge off. At minimum a carpet and a pad on 75% of the floor is a good start, which is a typical condo requirement. Double paned windows and solid core doors make a big difference. If those are not enough there are multiple vinyls for sound blocking and foams for sound absorption available, also Green Glue, and Quiet Rock.
Colleague Pete Fisler did extensive research which led to his use of the following method in his personal condo. The ceiling was dropped 1 1/2″ with metal channels, then applied with Green Glue sheet rock, which is a double layer of sheet rock with Green Glue product in between. He said it solved the problem.
Acoustic dampening materials can be put in the floor or the ceiling or both, depending on ceiling heights. In small buildings I suggest discussing with your neighbors the idea of installing sound reduction materials in all the units. Treat it as a building expense and pay for it collectively with the HOA dues. Teamwork is soooo much more fun than neighbor wars.
Thank You to Pete Fisler, Diane Hourany and Chiare Hwang.