What fitting(s) for plumbing toilet and shower into soil stack

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TullioK

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I am adding a new bathroom on the first floor of my house and there is limited space to run the drains to the existing soil stack.

I have bought a branch connector for the soil pipe (see link) and was hoping to be able to join the shower and basin drain into one of the 40mm side bosses but have read several accounts not being allowed to run multiple drains in at the same point because of the chance of cross flow. 200mm seems to be the recommended vertical distance required between branches joining a stack. However, I don't have 200mm of to play with in order to keep the falls for all the drains adequate.

I have looked through the relevant building regulations but cannot find any mention of this 200mm. I'm also curious as to why such a branch connector exists with soil and 40mm joins if it is not allowed. Perhaps the 200mm only applies to when the incoming pipes are directly opposite one another and it is OK to be at 90 degrees?

If it is not allowed to join both pipes into the above branch connector, then I'm hoping I could just fit one of this waste manifolds (second link) in below the branch connector order to have the pipes join closer than 200mm from one another.

If anyone could offer their opinion on the best way to proceed it would be much appreciated.

Thank you
 
Basin runs 32mm, shower runs 40mm, where they join increase pipe to 50mm then run that into the soil stack. Use a 50mm branch boss adapter.

Use an antivac trap on the basin.
 
Hi, thank you for your reply.

Are you suggesting I use one of these on the soil stack? (link to Screwfix item)

My issue is that the invert levels of the incoming shower/basin and soil pipe are very similar and there isn't the space to drop the basin/shower down 200mm below where the soil pipe will join. Hence why I was hoping to use the branch adaptor linked in my first post where they can all join at the same height. But I'm not sure if this is permitted..

If I'm not making sense I could draw a diagram.

Thanks again.
 
TullioK said:
then I'm hoping I could just fit one of this waste manifolds (second link) in below the branch connector order to have the pipes join closer than 200mm from one another.

If anyone could offer their opinion on the best way to proceed it would be much appreciated.

Thank you
Click to expand...
Go with that manifold if you can get it in;)
 
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