Project: Kitchen sink moved

[P.J.]

Hi All,
Project:
I'm moving my kitchen sink about 6 foot away from the outside wall - like an 'island' but the sink unit will butt up to the understairs cupboard at 90 degrees (in plan view). I need to get water supply to (that's sorted), and waste water from this unit and that's the problem - the waste.
The plumbing forum guys have suggested a macerator or installing a new drain under the new sink unit but I thought I'd put it out to all here for a bit of a brainstorm.
Any ideas ? e.g. run the waste into the understairs cupboard where there's a pump which will pump the waste water through a pipe laid in the kitchen floor and outside to the drain ?
Many thanks,
P.J.

 

[masona]

Floor screed or wooden flooring ?

Any plan drawing would help ?

 

[P.J.]

Hi masona,

Sorry for lack of detail. It's a concrete floor.

Regards,

P.J.

 

[P.J.]

Hi All,

Seems to be posing a problem - I've had a think and I plan to channel the floor to run the water supply and waste together in a plastic channel.
That'll mean a channel in the concrete floor of about 2 inches deep.

Does anyone foresee a problem with this ?

What run does the waste need for decent drainage ? 1 in ???

Cheers,

P.J.

 

[masona]

Sorry missed your post,

Have to think about this one, does the sink have 1 waste pipe or 2 ? (double or single bowl)

How far is the distance from the new sink position to the outer galley wall side ?

Do you know the thickness of the floorscreed on top of the concrete base ?

 

[P.J.]

Hi masona,
It will be one sink with a separate drainer, so 2 waste pipes but I guess these could be joined directly under the sink as the drainer wont be carrying away any volume of water.
It's about 3 metres from the new sink position to where the sink waste currently meets the outside drain.
I don't know the screed thickness but can find out if it's critical.
Island units are often shown in kitchen showrooms nowadays, do you know how the waste is handled in these situations ?
See the attached plan - I could run the waste left from the new sink position into the understairs cupboard and then lay a shorter channel in the floor upwards to the nearest outside point, then run a drain along to the existing drain.
Thanks in advance,
P.J.

 

[masona]

Island units are often shown in kitchen showrooms nowadays, do you know how the waste is handled in these situations ?

I have a island unit but the waste pipe go under the wooden floor joists and have a rod eye inspection on both end.

I could run the waste left from the new sink position into the understairs cupboard and then lay a shorter channel in the floor upwards to the nearest outside point, then run a drain along to the existing drain.

You could but it is the same distance if you went from the new sink poisition straight to the wall but less bend (only one 90 degree elbow this way). A lot depends on the thickness of the floorscreed, normally 50mm to 75mm thickness and you may get away with it. I would do it this way and I don't think you have much choice other than using a macerator type but it will need looking after plus noise problem(?)
From the drawing I think there is enough fall for what you want and put in a inspection eye on both end for rodding. About once a month I put in soda crystal to keep the drain clean.
The other problem I can see if you're going to use carpet, they maybe a weakness of cement on top of the waste pipe, might have to think about floor tiles or laminated etc.

 

[P.J.]

Many thanks, masona.

Think I'll push ahead with the direct route and see how it goes. Planned on having floor tiles so should be sound over where the pipes are.
Cheers,
P.J.

 

[masona]

Might be also a good idea to use insulation tape on waste pipe to protect the floor screed cement reaction to the plastic pipe. I know you do for copper pipe but not sure about plastic pipe

 

[AdamW]

I doubt very much it would react with the plastic, should be OK. I would definitely run screaming from the macerator idea, they are a lot of hassle in the longterm.

Will you be likely to have a dishwasher or washing machine draining through this pipe as well? I am wondering about expansion in this case. Less of a problem than with copper, but if you have appliances pumping very hot water down this pipe then it is worth considering.

 

[P.J.]

Thanks for the advice guys.

I've a washing machine and dishwasher just left of the current sink position. It's sounding like I need a new drain just outside, above and to the left of the current sink position on the plan, and runn all wastes into that, then along to the current drain. Something else to sort out !

Cheers,

P.J.