Covering copper pipes

[wingit]

Hi all,
I've lifted some carpeting in my flat and the central heating pipes (copper) run under a concrete floor, there is a hole in the concrete which someone has filled in with what looks like a kind of rubber filler, this has not held and peeled away. My question is, what is the best type of filler to fix/secure the floor, it's only a small hole 20cm in diameter roughly and the pipes are only a couple of centimeters below floor level. I am concerned that cement might cause the pipes to burst when expanding.

Grateful for any help on this.

Thanks

 

[gas4you]

Is it bare copper you can see or plastic?

 

[wingit]

bare copper

 

[gas4you]

You need to cover the pipes so the wet screed or whatever you use cannot contact the copper, otherwise it will eat into the copper.

Why is there an 8" hole in the floor? has there been a leak in the pipes previously?

 

[wingit]

Don't know why the hole is there, only just bought the place. The pipes are currently surrounded by small concrete (I think) balls, with a concrete layer on top for the floor, thanks for the advice.