i decided to remodel our small master bath shower that has a lead pan and ceramic floor that is a 42 years old..Bath is run of the mill with ( sheetrock shower).tore down to studs and removed tiles from floor leaving bare concrete floor over the lead pan.Never had a leak from pan.no stains on plywood looking up from basement and lead around drain looks shiny. after reading some post i learned life of a lead pan is twenty years due to oxidation between mortar mix and lead.My problem is i remodeled the main bath about four years ago using hardi backer on floor and added latex to my thinset so the bond should be super strong but the floors are separated only by the depth of a stud, so im scared to try to bust up the neo angled floor.Now not all is good with the lead sheet install.It appears lead sheet got a little out of square while trying to install as 6 inches up wall here while 3 inches here and rolled over curb only 2- 2 by 4 high then two more 2 by 4's stacked ON TOP of lead sheet with no drop toward floor . all rot damage around curb combined with bad door install=a lot of work for me.So the question is.... can i cut away the lead from around the floor and install a modern liner on top of my existing floor( there is no cracks or crumbling )then pour a new mix on top of that? I know i will have to remove the old drain. im hoping only a couple of hits will loosen it. I keep my beloved 71 plymouth below that pan so i do not want any problems. Thanks .Joe