Whenever I turn on heating, I can hear a sound of water drops on wood in the
first a few minutes after furnace starts and stops. The water drops quite
intensively at the beginning and then fades away after 5 to 10 minutes. I am
quite concerned.

Look at my furnace, there is a pipe coming out from the top of furnace,
leading to a drain on the floor. A similar sound can also be heard when
someone taking a shower, although the water only drops once or twice in this
case.

It looks to me that the water is formed by condensation, and it is supposed
to flow from the pipe out of heating system.

Here is my theory: before I moved into the house, one of previous owners had
bath room remodeled: ceramic tile on wall and floor. The quality of the
remodel is poor, from my point of view. There is trace of water leakage on
sides of tub, and also, faucet is loose and I am worried that someday
bathroom will fall apart. My reasoning is: whoever did the remodeling had no
clue about the condensation pipe and didn't connect the pipe at all.

I am thinking opening the dry wall to fix the problem. But I have never
worked on drywall before, plus I am not sure about my hypothesis. How
difficult to open and fix from drywall, and how should I approach this
problem?

Thanks for your advise.

Juping