Clunk well after water tub shut off

[beckthang]

Hello,

We've lived in a house for 6 months, no history other than it was rehabbed. For as long as we've lived here, anywhere from 20-40 minutes after the tub is filled, there is one "clunk" sound in the floor. We have open web trusses and the supply and sewer run through the floor. Occasionally there are two clunks, spread very far apart, but for sure one. It only happens with the bath, whether or not the tub is drained or not. It is not a series of clunks, just one. We've had a plumber over and of course, after waiting for 20 minutes, heard nothing and left.

Thanks for any guidance.

 

[speedbump]

Are you on a Well or do you have City water?

 

[beckthang]

City water.

 

[beckthang]

2 story house. master bath on second floor. 3.5 baths total, two on second. clunk seems to be coming from the floor when master bath tub (and once when) master shower has been used. hot water heater in basement and supply and sewer is with city.

 

[speedbump]

Hopefully, someone can help you with this. If it's not a well, I'm stumped.

 

[camaroderrick73]

Thinking its more like expansion / contraction that builds up . Nothing much you can really do...