"GB" wrote in message
How do you get a smooth enough finish to the floor to lay vinyl on and not
see the outline of the boarded trench? Lino may be a bit tougher, I guess.

You can buy those trays but getting it all flat is more work than
running the pipes on an existing floor. I think by law now you're
supposed to leave access and cannot bury directly in concrete but I
doubt many do.

Regards coating the pipes, I've used a bitumen paint to cover them
over rather than tape.