Bath Waste Pipe

24 Sep 2006
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United Kingdom
Hi, I am currently refitting our upstairs bathroom and have a question about the bath waste. I have fitted a new steel bath and have a McAlpine shallow bath trap going directly to the soil stack (approx 1.75m run). I now realise thanks to this forum that this is not acceptable as there is not a deep enough water seal in the shallow trap to feed directly into a soil stack. There is also a 32mm sink waste that is tee'd into the bath waste pipe about half way along.

So, I am wondering what my options are. As I see it I can either cut a hole in the floor boards to allow a full 'P' trap to be fitted or use a Hepvo valve instead of a water trap which will keep it above floor level.

My concern with the first option is that any leak from the bath waste connection will then drip directly onto the ceiling below rather than onto the floor boards below the bath where it can be more easily detected and sorted.

My concern with the second option is simply that I've never used one before and don't know the reliability of them.

Does anyone one have any suggestions or advice.

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Well that's one all then.

At least I know both options I put forward are viable options. I shall have a look into it and make a decision after Christmas. At the moment I have just temporarily made the bathroom usable again as we have the family coming to stay for Christmas so we wanted it in a working state.

I'm actually having a devil of a time getting the shallow bath trap to seal properly to the wste outlet and not leak. I made sure I got a good quality McAlpine one and the seal is in place and in good condition but when I fit it to the waste outlet it seems fine the first time it is used but then the next time it is leaking again from the waste connection seal. I've made sure to support the pipe at it's natural position so that there is no undue stress on the waste connection but it is still leaking. So I will be glad to get rid of the shallow trap anyway.

Thanks for the responses


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