Richard Fangnail wrote:

I'm trying to dull the tapping noise from the pipes in my ceiling.

Makes more sense to fix the tapping.

What materials could I use to deaden the noise?

You need something with mass and thats a problem with a ceiling.

I tried cork tiles but that had no effect whatsoever on the noise.

Because they have bugger all mass.

I've read that the idea is to use many layers of different materials.

Thats wrong. You wont get any better result with multiple
layers of paper, plastic and cloth in that particular situation.