11 year old screed floor cracked in corner and sounds hollow

[JP_]

Taken up the carpet in my living room as we are converting to a new kitchen diner. In one corner, within the bay window area, the screed has cracked and looks a little sunk. I tapped it with my knuckles and it sounds a little hollow too.

Is this likely to be a minor issue that I need not worry about, or a sign of something worse.

The house was built by barratt homes. The screed generally looks good.

Another strange thing - the other corner of the screed (about 1 m away) looked damp. But the builder had left a pile of stuff there earlier where the new window was installed, so that dampness may have been from there. I did not notice any dampness when I first took the carpet up.

My main worry / concern is that the mains water runs close to the cracked and sunk area. Maybe it caused some form of subsidence? But no other signs internally of any problems, and the builders have not mentioned anything that concerns them either.

As it happens I have a plumber coming round in the morning, and an electrician the following day, so I will ask them.

Note- not DIY, but this is the best forum for building related questions that I know of!

Thanks

Jon

ps I will photograph when it is lighter tomorrow.