Air admittance valve

[Bov]

Hi

We've relocated a toilet to the room next door (so soil waste is still connected to the outside soil stack). Due to space constraints, we've connected the sink waste (white pipe in image 01) into the soil pipe just behind the toilet frame (see hole image 02).

Will we need an air admittance valve adding in order to stop any syphoning from the sink trap? If so, given we're so tight for space, where would be the best place to locate it?

Thanks in advance

 

[Madrab]

Oh my, hopefully that's not the final setup for the soil pipe outflow? Could you not have gone left out of the toilet and through the wall there and then right to connect to the outside stack?

An anti-vac trap on the basin will be slickest approach to stop the basin trap from being pulled.

 

[Bov]

Thanks Madrab. Unfortunately we couldn’t do that as we’ve got a large brick gatepost in that exact spot, hence our plan B approach!