Stub stack - feeding into downstairs from upstairs

[mlgibbons]

Hi
I wonder if you can help me. I have a downstairs loo and an upstairs loo which are almost vertically aligned. The downstairs loo has an underfloor stub stack and the upstairs toilet goes horizontally through the garage to a different stack. I'd like to reroute the upstairs toilet down and into the stub stack. Physically this is viable as I can feed into the stub stack under the floor but I'm wondering if this is allowable? I'd presume that a AAV or similar would need to be fitted above the upstairs toilet's stack entry. Hoping to avoid a Saniflo.

Thanks
Mark

 

[basildog]

When you say underfloor do you mean no stack at the moment just a connection at floor level ?
A lot depends on if you still have an open vent on the system ?
This is normally at the furthest point on the line

 

[mlgibbons]

Hi
the downstairs toilet is on a suspended wooden floor with access to the 4ft high void under it. The toilet feeds directly into the drain using just an unventilated stub stack. I'd like to join the upstairs loo to this stub stack. The main drain is ventilated by another stack which the other ensuite feeds into.

Regards
Mark

When you say underfloor do you mean no stack at the moment just a connection at floor level ?
A lot depends on if you still have an open vent on the system ?
This is normally at the furthest point on the line

 

[AWheating]

i think the confusion in your post is because most people refer a stub stack as a small(stub) stack feeding a single ground floor room. Ie. being above the floor like a normal stack.

are you saying the downstairs toilet branches off from the main drain under the floor straight out the floor to the toilet only?

 

[Ermintrude]

I would say its fine. Pack around pipe with insulation. As when your mates downstairs using loo and your wife drops king kongs arm down the netty he will hear it.

 

[mlgibbons]

Yep. Under the floor the pipe, coming from the main drain I presume, rises straight out of the ground up to the toilet. No vent or anything. Waste from basin also discharges into this stack but I'd like to discharge the upstairs toilet into it too but looking at the regs I can see nothing relating to this.

Thanks
Mark

i think the confusion in your post is because most people refer a stub stack as a small(stub) stack feeding a single ground floor room. Ie. being above the floor like a normal stack.

are you saying the downstairs toilet branches off from the main drain under the floor straight out the floor to the toilet only?

 

[basildog]

Yes sounds fine to do as you plan .
Yes if you are boxing it in then use some form of sound insulation as I too hate that noise you can get !
Most use fibreglass but actually fibreglass has vesound proofing qualities .
We used to build ply boxes and fill with dry sand soon learnt you had to really seal the joints !

 

[mlgibbons]

Super. Thanks to everyone for the advice. Much appreciated.

Yes sounds fine to do as you plan .
Yes if you are boxing it in then use some form of sound insulation as I too hate that noise you can get !
Most use fibreglass but actually fibreglass has vesound proofing qualities .
We used to build ply boxes and fill with dry sand soon learnt you had to really seal the joints !