Background

I have a crawlspace under my house.
House is 6 years old


Problem,

when pipes have been sitting for a while, (few hours) the pipes make a lot
of noise when you open any faucet. particularly any hot water faucets.
The pipes make a ticking rubbing type sound that stops after a minute or
two, even if the water is still running.
I will be selling the house inside of a year an a half, and I would like to
stop this from happening as the noise is surprising the first time you hear
it, especially in the kitchen where the ticking / rubbing comes from right
under your feet.

I've been told that the noise comes from the pipes expanding as warmer water
runs thru them, and the pipes are rubbing on the wood joists.

does anyone have a good fix for a problem like this? all the pipes are
still accessible, thru the crawlspace, (though a little cramped)
if I loosen off the hangers will that take care of the problem?

one of the real problem spots is where the hot water pipe enters the
crawlspace thru the wall from the garage (where the hot water heater is)
is there some type of grease or ?? that I could stick on the pipes that
might work as I can't really enlarge the whole that the pipe passes thru.

Thanks

Dave