Sink waste into sewer

[wozza]

Hi Guys,

 

I am converting the existing garage to a bedroom. There was previously an open gully type drain trap that the waste from a sink from the other side of the wall ran into via a 32mm pipe. The sink pipe cannot be easily routed anywhere else inside the house.

 

In the picture you can see the existing clay sewer pipe and the 32mm pipe from the sink (it goes into a 40mm horizontal section), the red dotted line shows the approximate bottom level of the concrete sub floor - basically I need to connect the two pipes below the sub floor, I have a plan and a few questions as follows:

 

My plan is to rotate the clay pipe 90 degrees to the left, fit a small length of 110mm pipe, then a 110mm bend and then the new 32mm to 110mm adaptor, this will keep the 110mm pipe and fittings below the concrete subfloor.

 

1: Can the sink pipe be chased into the wall by about 20mm to prevent it being too far into the room as the wall is going to be plaster boarded?

2: Am I ok to use 32mm push fit elbows / 45s to bring the pipe out from the wall chasing (if ok) to allow it to connect into the 110mm adaptor or should I use solvent weld as they are less bulky?

 

Any feedback, other ideas or suggestions are welcome, thank you, Wozza.

 

Edited October 16, 2019 by wozza

[PeterW]

Any chance the sink can be routed inside the other room to come out further down the wall..??

 

Is that wall one skin or two skins of brick ..??

 

I wouldn’t try and rotate that clay elbow as you could either shatter it or shear off the pipe further down. The joint will also weep as it will be a concrete sealed joint. 
 

I would find the joint and dig out the elbow, convert to UPVC and then do what you’ve said with 110mm. An offset adapter will get you close to the wall too, but if you can get to the back of the other wall and then either core or cut the bricks and come in at 45 degrees below ground level. Not ideal having joints like that below ground but I would also convert to solvent weld.  

[wozza]

Hi Peter,

 

The sink is a pedestal sink, so if the pipe were to be lowered it would be seen and unsightly.

 

Its a cavity wall, block inner, brick outer, it was double height but the wall above has been removed to extend over the garage.

 

The clay elbow has rotated ok as it is connected with a plastic sleeve.

 

My main concern was if it was ok to chase out the wall.

 

Also would it be better to use a flexible solvent weld connector from the 110mm pipe through the floor so there are no joins in the concrete / insulation / screed - something like this: https://www.toolstation.com/mcalpine-flexi-waste-connector/p58975

 

Thanks, Wozza.

Edited October 16, 2019 by wozza

[PeterW]

Definitely do not use a flexible pipe .!!

 

You can hide pipes in pedestals - it is what they are for.  Just turn the trap so it exits toward the front and use a 90 knuckle and the waste will track the inside of the pedestal. 
 

cutting into that wall half of its depth isn’t a problem either - try and get the 110 partially recessed too - using one of the multi adaptable bends may help you there as it’s only a waste pipe. 

[wozza]

Thanks Pete.

 

All done

[PeterW]

7 hours ago, wozza said:

Thanks Pete.

 

All done

photos ..???