The roughin plumbing for my basement bathroom has a 1-1/2" drain pipe which i suppose was meant for a bathtub. i want to install a shower. i am in canada (alberta), can i connect a 2" drain tailpiece/2" p-trap to this existing 1-1/2" drain or am I going to be faced with ripping up the floor to install a larger drain?

Dang, 30 people have had a look at this and not a single suggestion or comment. After much deliberation and a ton of surfing I believe I have discovered my own answer. I am going to cut out the entire bath 1 1/2" drain. alot more work but i know i'll sleep easier. my research said i could reduce to a 1 1/2" but should do it right after the 2" tailpiece. But I did hear see quite a few comments recommending not.