Do I need Air Admittance Valve??

[jonjack]

Hi


I did find quite few threads on this already here but not one that answered my question.

I have a 2 story-semi with 2 existing upstairs toilets currently discharging into a singe exterior vented stack.

I am fitting a new WC in downstairs cloakroom and am intending to run the new waste into the base of the existing soil stack by using a triple socket branch.

Do I need an Air Admittance Valve in the downstairs cloakroom?

Also, is it acceptable to just join up the waste from the small basin I am installing in the cloakroom into the new waste from the toilet?


cheers

 

[plumber0808]

Yes will be fine to run a new toilet in to the stack without extra vent as it is already vented. Also fine to run basin waste into it aswell

 

[PlumbBobBob]

it's only if you have a completely new soil run when you would need an aav. as plumber0808 said no need as you are joining to an existing vented stack.