Moving kitchen sink and drainage

btcp

We are planning our kitchen remodelling and wanted to move a kitchen sink and a washing machine a few meters away to the other side of the kitchen. I had a builder coming in who said that I need to figure out if that’s possible, because there may be not enough fall for a drainage pipe, as my drainage in the garden is quite shallow. So the question is, who can help
me to figure it out? Do I need to call a drainage person, or is it a local Building Control? I’d like to understand what my options are in terms of the layout before I apply for a planning permission (we can also build a small extension and add laundry there but I first want to see if there is a cheaper way). Thanks! 

Teapot55

Take some measurements: how far the drain is from your u-bend and how much higher the u-bend is than the drain. Do the same for where the new sink will be. With that information there’ll be people on here who’ll have some answers. 

You could also ask more builders to come and quote you for the work. 

btcp

At the moment the drain is roughly 4 meters from the sink. We want to move it further 5 meters so it will be 9 meters distance. This will also have a turn, as the sink is in the center of the room but the drain in the garden is about 1.5 meters to the left from the center. The drain is shallow, when I open the lid I can reach the bottom with my hand (in my previous house the drain was a around a meter deep).

plumb1_2

Do a sketch and post it, floor level the same, it’s just the distance?

Alderbank

Best practice is that the slope of the waste pipe is between 1/40 and 1/110 for good drainage. I usually round to between 1/50 and 1/100. For a 9 metre run that would be a minimum of about 100mm. 
Work out where the horizontal output of each trap will be then measure to ensure that the end of the waste pipe can be 100mm lower and still be above the drain entry point. The sink should be OK but the washing machine standpipe outlet is much closer to the floor and might be a challenge.

markin

What is the measurement from floor level to the top of the drain gully, Unless its 40cm the drain/trap probably needs moving closer.

Or even run a main drain under the floor

btcp

Thank you all for your answers. Attached is a drawing of what I am trying to do. Looking at the recommendations above to have 100m fall, I am not sure if my layout  is feasible? 

Currently drain pipe output from
the sink to the wall is 40cm from
the floor. I would assume it will be the same on the island? 

btcp

Wondering if my drawing make sense and if someone could confirm if what I want to do is possible? Thanks 

markin

As its an island you only have the fall from under the floor to play with and not from the sink P trap. Is the kitchen floor raised up from the outside ground level? As posted above you need a minimum of about 100mm drop.

How far and deep is the manhole?

If the outside drain is a P trap you have less height to play with.
https://www.diy.com/departments/floplast-underground-drainage-low-back-p-trap-dia-110mm/80951_BQ.prd



Bottle Trap

 


 
 

btcp

markin said:

Is the kitchen floor raised up from the outside ground level? As posted above you need a minimum of about 100mm drop.

How far and deep is the manhole?

If the outside drain is a P trap you have less height to play with.
https://www.diy.com/departments/floplast-underground-drainage-low-back-p-trap-dia-110mm/80951_BQ.prd



Bottle Trap

 


 
 

The kitchen floor is not raised, it is the same level with the garden. 

The manhole is 8.6 meters from the planned island, sorry if it wasn’t clear from my drawing. The depth to the top of the waste pipe in the manhole is 18 cm. 

I am not sure about the p trap, everything outside is underground. 

It sounds to me that I might have a problem with not enough fall. I saw people on the street having an island with sinks, I am wondering how they did it. I can try to knock their door and ask… just curious. 

Alderbank

Is your kitchen floor a suspended timber floor or a solid floor?

Which ever it is, from your description I think you are going to need a grey water pump such as  Saniflow Sanivite. This costs about £500 plus installation.
Because of the popularity of island units quite a few models of grey water pumps are now available from different manufacturers. Hopefully people who have fitted these will give feedback about their experiences and recommendations.