Help with long waste run for kitchen

cpbackhouse

Hi

Hoping for some advice please.
We are looking to replace our kitchen in the near future and add a door to the garden from the dining area. The problem we have is that the kitchen is in an extension and currently the sink/dishwasher waste was just extended to go across the bottom of the window, we want to make into a door, to the soil stack in the corner about 5m away.
There is a second soil stack in the utility room but using this would mean running a waste around the whole kitchen about 8.5m which doesn't seem ideal.
The floors are solid and I can't find any obvious evidence of drainage out the back to create a completely new waste run easily.
Here is a rough sketch what it looks like.



I'm assuming for such a long run I should look at a pumped solution and have been considering a Saniflo Sanivite+ or a Grundfos Sololift C3.
In the spirit of moneysaving though I was wondering if I definitely need to pump or if anyone has any alternative ideas.
If I do need to pump does anyone has any experience with the above pumps or has any other recommendations please.

Thanks for your help
Chris

Hasbeen

Can you not run a new exterior underground pipe from the dining soil stack to outside kitchen window?  5m trench.

If not then you could run a 50mm solvent weld type piping along green route behind new units with an appropriate minimum drop I think of 25mm per metre?

Would not put any pumps etc in at all.

cpbackhouse

Thanks, I had wondered if using a bigger diameter pipe might be a solution.

If I went that route would it be worth adding some Y pieces for access if it ever needed cleaning?

FreeBear

Hasbeen said: Can you not run a new exterior underground pipe from the dining soil stack to outside kitchen window?  5m trench.

Even better if there is an inspection chamber (manhole) at the rear. But.... Any new connection to a foul water sewer would need to be building regs compliant (and should be signed off by Building Control). Whilst it may be an expensive job, it will save on having pumps serviced or replaced as well as reducing the risk of blocked pipes.

Hasbeen

FreeBear said:

Hasbeen said: Can you not run a new exterior underground pipe from the dining soil stack to outside kitchen window?  5m trench.

Even better if there is an inspection chamber (manhole) at the rear. But.... Any new connection to a foul water sewer would need to be building regs compliant (and should be signed off by Building Control). Whilst it may be an expensive job, it will save on having pumps serviced or replaced as well as reducing the risk of blocked pipes.

Yes that would be better. Only gave the OP the option to run to soil pipe for below ground connection as OP stated "I can't find any obvious evidence of drainage out the back"

OP are you sure no signs of any drainage / covers / rodding points etc at back?

OP you could put in 92.5% tee's and access caps. But the way you would be running the pipe is behind the new kitchen units in the services void space? So not usually accessible? I would not run pipe through inner parts of the unit either, just to get access.
Sufficient SOLVENT waste pipe diameter, Good fall to soil pipe and good easily accessible trap at sink would be what I would go for.  

My opinion only though LOL

Homer_home

Or move the sink and dishwasher......

Don't know why there is this obsession with putting sinks under Windows

Hasbeen

Homer_home said:

Or move the sink and dishwasher......

Don't know why there is this obsession with putting sinks under Windows

Or take down the wall and incorporate the utility area to make huge kitchen. Worktops/Units on 4 sides.

cpbackhouse

Thanks for all the suggestions.
if there is a manhole cover out the back the previous owners have patioed over it.
There is one just outside the utility room. I’ll try and have a look later and see if I can work out if they are all flowing into the same one or if there should be another one around the back.

Thanks Hasbeen, I was thinking creating some access holes in the back panels of the cupboards.
With the current location of gas and oven electric points I think the sink location is probably relatively set. Would be interesting to open everything up but I think with the way it has been extended already there might be a large amount of steel involved!
Thanks again all ....

Doozergirl

Homer_home said:

Or move the sink and dishwasher......

Don't know why there is this obsession with putting sinks under Windows

This!   

Get a dishwasher, then no one needs to obsessed by looking out of the window and washing up.  

Electric points can be moved pretty easily, in fact, I think it's better to start with a blank canvas and come up with the best design rather than being constrained by someone else's design that could be terrible.    It wouldn't cost any more to just move some electrics than buying a pump, which would also need electrics.  

rob7475

If you use 50mm pipe with sufficient fall it will be fine. My kitchen sink is on a peninsular in the middle of the room. It's about a 6 metre run to the stack. I used 50mm pipe and added an air admittance valve which eliminates gurgling on long runs. It's been in for nearly 7 years and has a sink and dishwasher into it with no issues

Homer_home

rob7475 said:

If you use 50mm pipe with sufficient fall it will be fine. My kitchen sink is on a peninsular in the middle of the room. It's about a 6 metre run to the stack. I used 50mm pipe and added an air admittance valve which eliminates gurgling on long runs. It's been in for nearly 7 years and has a sink and dishwasher into it with no issues

Agree, but I'm not sure the op is aware of the work involved in running a new large pipe behind their kitchen units

They are going to have to pretty much dismantle their entire kitchen to run it and there will be a large amount of cutting the units to fit in around it also can't remember if the service void is deep enough to accommodate 50mm pipe 

Op are you going to be doing the work yourself?