In my view it is a mistake to allow yourself to become dependent on silence. It creates a crutch and it does it without needing to. With practice you can become accustomed to the steady humm and chatter of cafes and other similar places. But you need to persevere. The reward is that it empowers you to be able to write in a much wider range of places. Also experiment with classical music such as solo piano, solo guitar, piano jazz etc tinkling at low volume.
In some ways, I second this. I see privacy as a far more important factor than silence. The library I use is actually less quiet than the more easily accessible one (it uses humming ceiling fans and there are always people leaving their stuff in the lockers when they come in and leave, causing a clatter). That said, I don't see silence as a drug you can become tolerant to over time and then require to maintain creativity. It's just a bonus, really. And, if you do get used to it, there are always earplugs
