Basin Waste Connection to Soil Stack - Confused

[MrMagoo72]

Hi Guy’s,

I’m new to this forum malarkey so please be gentle with me.

I have a basin waste pipe to soil stack connection question that I need a little help in answering. Prior to that, let me give you some background information. Here goes; I recently decided to convert my shower room [which is directly next to the main bathroom] into a room to house a secondary toilet. The soil stack already has a toilet boss and waste fitted (I actually didn’t know that until I ripped out the shower tray and associated wooden panelling).

The question is as follows;

My Dad showed the image [as shown] to a bathroom fitter that is currently working on my brother’s bathroom. He mentioned that the 32mm waste boss is too low and would be prone to blocking if a secondary toilet is used. He suggested fitting a new boss higher than the toilet waste to prevent this. I’m not entirely sure whether that is correct or not and would really appreciate any thoughts or ideas. I see no point cutting in a new waste boss above the toilet waste if it’s not needed.

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Thanks all

/C

 

[Nige F]

Google Marley soil stack - all will be revealed When you ripped out the old shower etc. was that soil pipe open ended like that

 

[MrMagoo72]

Thanks Nige,

The open soil pipe actually has a cap like device inserted inside [sorry for the non-technical wording - lol].

 

[muggles]

If the RH branch of that cross tee isn't going to be used for a toilet you could reduce that down to 40mm for the shower instead, that'd work fine

 

[MrMagoo72]

Thanks Andrew, I'm installing a secondary toilet and was told that the 32mm boss [located below both toilet wastes] that I was going to use for the basin waste would be prone to blocking :/

I'm still confused....

Thanks


/C

 

[Madrab]

If you open the 32mm boss up on the stack, where it is positioned, the outlet inside the stack could catch solid waste from either of the toilet outlets with them being so close. If both toilets run at the same time they could also cause syphoning of the sink trap, easy sorted but better to avoid.

Usually you would put a solvent weld 40mm or 32mm strap on boss at least 100mm above the toilet outlets, to avoid any of those issues.

 

[Nige F]

Why put the boss there if it can block - and show it connected to a waste pipe in the Marley diagram I referenced Flying Richard111's

 

[Madrab]

wouldn't be the first time a design hasn't worked every time.

Have been called out to blocking issues for that very reason where all the boss' have been used.

 

[Nige F]

Fair comment

 

[longdogs]

If you don't fancy connecting a new strap on boss you could always use a pan connector with a 40mm boss connection.

Fitting a strap on boss is an easy job though.

 

[MrMagoo72]

Thank you all, I'm going to cut in a new boss into the soil stack. Watch out for my new thread regarding replacing a soil stack lol.

Thanks again

/C