Kitchen sink drainage directly down in slab or outside?

[Sunil237]

We are having an extension where we have a kitchen sink on the external wall, and I've told the builder that I want it feeding into the ground internally and connecting to the drainage system that way. At the moment he's built to DPC and is getting ready to lay MOT type 1... I would have thought the 110mm would need to be in place first. Am I wrong??

Below is the closest image I can see that represents what I wanted.

 

[Russell griffiths]

If you want it internal y then he should have run a pipe already and a concrete lintel over the top of it where it goes through the walls. 

[ProDave]

At what point in the construction did you tell the builder you wanted internal drain pipes?

[joe90]

I did similar to above but used 50mm pipe through wall and up.

[Sunil237]

I told him before he did the foundation, which is why he's put a concrete lintel over a drainpipe I'm using for a MDPE water pipe.

 

I assumed he would have just core drilled through for the waste drain with a 40mm but now I've seen the picture I don't think my understanding was right 

 

@joe90 thanks, this might be what he was thinking. Would the 50mm fit to a particular type of 110mm drain pipe part?

[joe90]

27 minutes ago, Sunil237 said:

Would the 50mm fit to a particular type of 110mm drain pipe part?

I used one of these and a p trap 

[Temp]

I think he's forgotten. We have our kitchen sink on an interior wall. Builder ran 110mm through the foundations and up through the floor. Adaptors down to 40mm. 

[Sunil237]

Thanks @joe90 that's helped me figure out the plan

 

@Temp unfortunately it's not that he's forgotten.. he just didn't know the correct way so it's going to be upto me to spot these things earlier as we go through. Luckily not the end of the world, as his scope of work is fairly limited

[joe90]

1 minute ago, Sunil237 said:

he just didn't know the correct way

This is why every little detail needs to be ironed out in advance , never assume anything. Planning, planning, planning.

[Sunil237]

Just now, joe90 said:

This is why every little detail needs to be ironed out in advance , never assume anything. Planning, planning, planning.

agree, I was just caught blind by my trusted builder who had an injury and had to back out the job a week before starting, he worked with my on my previous reno 8 years ago and all I needed to say was 4m extension with a pitched roof and it was done within weeks to a great standard.

We've planned a lot out but I've lost a month and had to find 4 different people to cover my original builders scope so struggling to stay afloat let alone keep ontop of the details I expected the tradesmen to know and flag up. Luckily my electrician and plumber are top quality so that should ease my burden a bit

 

[Russell griffiths]

If you are running multiple things into this drain

sink-washing machine- dishwasher it’s probably better to bring the 110mm up into the room and then reduce down to 50mm. 
you also don’t need the bottle gulley outside but can go direct to an inspection chamber. 

[G and J]

7 minutes ago, Russell griffiths said:

If you are running multiple things into this drain

sink-washing machine- dishwasher it’s probably better to bring the 110mm up into the room and then reduce down to 50mm. 
you also don’t need the bottle gulley outside but can go direct to an inspection chamber. 

That’s what we are doing, with an automatic air valve.   Presumably that’s another thing I need to tape up for my air test?

[Sunil237]

 

36 minutes ago, Russell griffiths said:

If you are running multiple things into this drain

sink-washing machine- dishwasher it’s probably better to bring the 110mm up into the room and then reduce down to 50mm. 
you also don’t need the bottle gulley outside but can go direct to an inspection chamber. 

Is there any harm in just core drilling through a 110mm and putting an elbow inside and connecting this to the inspection chamber? a it's too late for a lintel

 

There will be sink waste (from an sink grinder) and dishwasher only

Edited January 7 by Sunil237