Adding shower waste to stack

[dabaldie]

My house has a twin stack waste. Its not strictly correct, in that the bathroom sink and bath discharge into a CI hopper which also takes the roof drainage. Is this contrary to regs.. its been like that for at least 5 years (previous owner).
my second question is: I have just added a shower cubicle and ive connected the waste to the main foul (toilet) stack. I used a strap on boss and sealed it using roof and gutter external sealant. I also made sure i connected the boss the correct height away from the toilet connection to comply with regs. Am i correct in thinking that i should have informed Building Control that i modified the stack?
btw it all works lovely at the mo.... any major problems likely in the future?

 

[Bahco]

Your house drainage may be a combined system so both surface and foul water can discharge into this. Phone BCOs for clarification.

With regard to your modification, BCOs are mainly concerned with underground changes so should be no problems with your installation.