Waste water drainage for 2 baths and washing machine

[hayati]

Hi,

Installing 2 new bathrooms, property only had 1 bathroom and the waste went into a cast iron soil stack which has now been replaced.

I really don't want to notch the joist to get the waste out. I was thinking can I run the waste connected together to the outside in 40mm?

So the bath waste from the top floor connects directly to the bath waste on the middle floor (directly above the top bathroom) which then runs directly down to the ground floor where it connects to the washing machine waste and out into the soil stack. Will this cause issues?

Many thanks in advance
Den

 

[Timmy D]

Yes, you’ll likely have issues. Max length (building regs) for 40mm is 3m as long as you stick within capacity.

Take them out the external wall into a stack.

 

[hayati]

thanks Timmy didn't know about the max length for 40mm. looks like it'll be far too long then so ill have to resort to plan B by drilling through the joist