We have had the plumbing roughed in for several years for a basement bathtub, but we are just now getting ready to install. When we originally started this project years ago we were told we would have to chisel out a 12" square surrounding the tub drain in the cement to allow for ventilation (this seems a bit excessive). I've also been told that the builder would have allowed for ventilation when the drain was installed. We are pretty clueless with plumbing questions & have considered hiring someone to install it, but we would prefer to do the work ourselves. Any help would be appreciated. Thanks!

When we originally started this project years ago we were told we would have to chisel out a 12" square surrounding the tub drain in the cement to allow for ventilation (this seems a bit excessive). I've also been told that the builder would have allowed for ventilation when the drain was installed.
This is called "The Tub Dap Out" ,(see image) and has nothing to do with ventilation. It is there for the trap and should have been boxed out wher the slab was poured. You shouldn't have had to chisel out a thing but if there's no square hold you will have to expose the trap by yourself. Good luck and thank you for rating my answer. Tom

Thanks for the answer Tom. We actually haven't done any chiseling yet. Would we have to elevate the tub at all? Thanks!