Soil Pipe Alterations

[SouthDIYJon]

Hi All, Can anyone advise to where I stand with building Regs, if I was to cut the Soil Vent pipe off below bath level and fit a one way admittance valve. If this is not possible due to Regs what size can I reduce venting pipe down too.
Said Soil Pipe has One toilet bath and sink waste entering it.

Many Thanks John

 

[Newboy]

The AAV needs to be fitted at a minimum of 300mm over the highest overspill level of anything connected to it - ie 300mm above the lip of the bath/basin/WC connected to it - in your case I would assume the basin would be the highest level.

 

[SouthDIYJon]

Thanks newboy, I guess from your reply then I will have to reduce size of soil vent pipe, as I cannot have soil vent pipe above bath level. I am trying to gain rom in corner of room to move bath over, as room size is small.
Many Thanks John

 

[Blagard]

The ventilation part of the stack should not be less than 75mm diameter and in any event should not be replaced by an AAV unless you know the head of the drain is fully vented elsewhere (open ended vent)

 

[SouthDIYJon]

Thanks Blagard, for your info. I ve noted what you've said and will act accordingly. I think I will me replacing soil vent with 75 mm and take things from there.