I am planning to upgrade my kitchen this year, and I'm hoping to move the position of my sink. The room is at the corner of the house with 2 external walls. The sink currently sits under the window on the U of the current layout on the short external wall.
I would like to have a galley with two straight runs opposite one another along the long external and internal walls, with the sink on the internal wall.
The drainage from the sink (and dishwasher) would need to run behind on unit to the side of it, turn 90deg, and run along the short wall to the drain which is outside right on the corner. It will just be the sink and dishwasher - no other water using machines in there.
Ideally I would like to keep the short wall run below the plinth level - which will be 125mm. That wall is 2.42m and the pipe would have a 6cm fall (which is a 1:40 gradient) and would come out 3cm above the indoor floor level.
My rather rough diagram shows my preferred run in yellow, there is a pic showing the internal wall run to show where sink will hopefully sit (it's not finished yet - just included to make things clearer), the pic of the drain shows the indoor floor level marked by the red line - the white pipe is the current kitchen waste pipe which exits at 26cm above floor level.
I need to know if this will be able to work in order to progress with kitchen planning. Is a steeper gradient before a corner turn and then a shallower gradient ok?
Is it ok for the exit point to be much lower down and closer to the drain?
I am politely hoping that @pigletjohn might be able to offer me some advice 🙂