Bathroom Waste Pipes

[tjw1701]

Hi All.

I am currently fitting a new bathroom, and am placing most items in new locations. I have worked out where I am going to run the waste pipes, but have a few questions about connecting them to the stack pipe.

My house has a flat roof extention on the side, which would make modifying the waste stack very difficult. I have discovered an unused connection most likely from the original toilet under the floor, but there is nothing for the sink bath or shower. I could possibly drill a new hole under floor level out to the stack, (which is actually in the roof of the extention) BUT.......the stack pipe is made of (I think) cast iron, which I understand is very difficult to work with, especially in the cramped location it currently is.

The toilet is in line with the 4" connection T under the floor, so connecting that should be easy. The question is can I connect the waste for the bath, sink and shower to this pipe without issue, or am I likely to get air trap problems when the toilet is flushed. I have read somewhere I could connect another 1 1/2" pipe to the stack higher up (which in this case is plastic so easier to cut) to create an air vent, but is this standard?

Sorry for all the rambling and I hope it makes sense.

Thanks in advance for your help.

 

[gasmick2]

i suppose you could put a strapp on boss on the cast soil stack once you have drilled it out and debured it and sealed the boss to the pipe use the ones with a bolt that goes at the back to clamp it together then you can use anti vac deep seal traps on the sanitaryware and if you wanted to you could put an anti syphon pipe 1 /1/2 from the rear of the wc connector and take it up the stack back to a boss pipe just to be shure if you have the room
we used to run a seperate 2 " anti syphon pipe in flats years ago to stop traps from being pulled

 

[tjw1701]

Great thanks for that.....I think I will try putting in an anti syphon pipe into the waste pipe above floor level. Since it is under the bath it will be hidden, and where it would meet the stack it is plastic rather than cast iron so much easier to work with.

Thanks for the advice!

 

[Timmyturtle]

If you should connect to the cast iron ,you may need to chain drill it to create the hole .Use a strap and boss ,using a good amount of silicone sealant to seal it
I have done it as a last resort and it works fine

 

[tjw1701]

Sorry to sound dumb, but could you explain a chain drill. Having looked into it further, I think I am going to have to connect the bath shower and sink together, and run a 40mm pipe to the main stack, this will involve attaching it below the entry point for the toilet, thus into cast iron. I have never drilled cast iron, and have heard stories of it cracking. Any advise would be great.

 

[tjw1701]

OK, so now I really look stupid. I dont thing the blimin thing is cast iron after all, it appears it could be asbestos. I dont know if you know any way to confirm this. If it is asbestos then drilling it would most likely be a no no right. Should I just remove it alltogether and get a plastic one fitted. I dont really want to have to do that as it would knacker the flat roof, but if thats what its takes........... I dont suppose there is any other material it could be, it certainly is not metal. The house was built in 1965 if that helps.