Can someone tell me how to drown out noisy pipes in the home?

Can someone tell me how to drown out the noise from knocking pipes. Everytime my neighbor or I turn on the hot water, the pipes began to knock and takes hours to stop. It’s right behind my bedroom wall. Moving out is not an option. I can’t afford to. The complex put in insulation foam but it didn’t help at all.

Nichole,
Here’s your problem: You have calcium/lime build-up inside your water heater. The problem is not from not having the pipes strapped properly.
There are three possible remedies to this problem:
1) Drain the water heater at the drain valve at the bottom of the heater. Connect a garden hose to the valve and allow the water and calcium deposits to drain from the tank. This is the easiest and cheapest way to solve the problem.
2) Replace the water heater. This may be a wise choice if the heater is old and past its life expectancy.
3) Install a water softener. Soft water will eventually dissolve away the lime deposits, but this choice will be more expensive and take a few months before showing any results.

how much does a sheet of rigid insulation foam weigh?

I really dont care about anything other than the weight. lbs or kg is fine
either 1/4 inch or 1/2"

How thick?

what is the best type of foam insulation?

i need a Foam Insulation for the home as a substitute for the fiberglass ones? any suggestions? please explain as to why your answer is the best one
thank you

Rvalue is better foam fills in more space, but requires skilled installer.