Soil stack AAv

[Biggles..]

Hoping some of the plumbers on here might be able to answer this problem. Started working on a new extension to a house. The original soil stack is remaining but will end up interfering with the new roof. Question is can the stack have an AAV fitted and terminate in the new roof space or does it have to be open to atmosphere. One point to note is the house in question is the last house on the main drain/ sewer pipework.
Lee

 

[ACOperson]

Never do any drainage work myself, but I'm sure it will NOT be possible to terminate a soil stack inside a roof space.

There must be a way to re-route it so that it can go through the roof or something?

 

[Gasguru]

Check with BCO - he's the one signing it off

 

[Biggles..]

There will be a way through the roof just gives the roofer a bit more lead work to do. the guy who's house it is works for a builder who does new build, they terminate some of their stacks inside vented roof spaces with AAV's but his boss thinks cos he's on the end off a run you cant. never come across it myself normally all my stacks are external even with a AAV. Cant find a mention in any of my old drainage books either.
Lee

 

[Bahco]

The stack has to be open to vent the sewers.

AAVs are only to allow air in to a stub stack to prevent loss of trap seal.

You will find that BCO will not allow (I tried it 2 yrs ago).

You will have to route it so that it terminates 900 mm above the window if it is within 3 metres of it.

 

[Nige F]

Your books must be older than mine .............have a look @ Marley drainage website .....still can`t do it tho` Mine are 25+yrs old

 

[Biggles..]

Books are old CITB cold water and drainage back from my apprentice days 11 yrs ago. Thanks for advice looks like its through the roof.And your right your books are old.