Originally posted by fourth year:
In that case you would have to bring the pipes up from the floor and have never had to deal with a solid pedestal that only has the trap recess. In addition, tightening the trap is tight enough without trying to work around water pipes in the recess. and to not have the waste visible would require an illegal “S” trap and no pedestal has room for one of those AND the water piping. Are you sure you have ever installed a true pedestal lavatory?
In Britain a trap is available where the basin waste outlet fits to the top and waste pipe fits the opposite end. If you source basin by Armitage Shanks or Ideal Standard, the practice I wrote about is possible. Yes I have installed many basins where the three pipes are enclosed by the pedestal