kitchen waste but no outside wall

[gummy bears]

Hi All,

So the kitchen faces the back garden at the moment. The waste leaves the sink through the back wall and falls into an outside gully (you can see the waste water come out when the kitchen tap is on). That is the standard setup I believe of most houses.

But now an extension will be built on the back of the kitchen but the kitchen will remain in place.

How should the waste now be plumbed so it can still be easily unblocked - I think you are not allowed to use internal manhole things even the mini ones?

Thanks.

 

[delmel]

I had mine done, the builder and plumber put in a small flush sealed drain and terminated the waste into that and out of sight and also a sealed flush man hole cover, both of which could be unscrewed in necessary. Thankfully in 15 years we have never had to.

 

[gummy bears]

I had mine done, the builder and plumber put in a small flush sealed drain and terminated the waste into that and out of sight and also a sealed flush man hole cover, both of which could be unscrewed in necessary. Thankfully in 15 years we have never had to.

thanks for the reply delmel.

but you said 15 years ago - I think the law has changed and we cant do it that way now. So im wondering how can it be done now if you cant use that system?

 

[Hugh Jaleak]

Gulley will have to be removed, and a sealed connection made directly to the drain, assuming the drain run is accessible from a chamber elsewhere. Otherwise look at a stub stack, but I'd want external access for cleaning personally. Kitchen wastes can get gunged up with fat, grease, food waste, soap etc, and I wouldn't want to be trying to clean it out from inside the building.

 

[Si_the_Plumber]

Can you not just move the gully to a new position, like the side of the house and re-route the waste pipe?

 

[gummy bears]

I had mine done, the builder and plumber put in a small flush sealed drain and terminated the waste into that and out of sight and also a sealed flush man hole cover, both of which could be unscrewed in necessary. Thankfully in 15 years we have never had to.

building control officer came today and he you CAN have double sealed flush man hole thing as long as it's on a private drain which mine is. (If it's shared in anyway that's when you cant use them).

This will make life a lot easier I think.

 

[gummy bears]

Gulley will have to be removed, and a sealed connection made directly to the drain, assuming the drain run is accessible from a chamber elsewhere. Otherwise look at a stub stack, but I'd want external access for cleaning personally. Kitchen wastes can get gunged up with fat, grease, food waste, soap etc, and I wouldn't want to be trying to clean it out from inside the building.

thank for the reply. no chance of having anything outside. one side is the neighbour (semi-dethatched) and the other 3 fall inside the rest of house or new extension.

 

[Hugh Jaleak]

No problem. It would be pretty rare, (but not unknown) for a kitchen drain to block up, given the usual causes are fat, grease etc, cleaning them out isnt a pleasant task, and ideally I would want to do from outside, but if it cannot be avoided then you'll have to take that chance.

 

[gummy bears]

No problem. It would be pretty rare, (but not unknown) for a kitchen drain to block up, given the usual causes are fat, grease etc, cleaning them out isnt a pleasant task, and ideally I would want to do from outside, but if it cannot be avoided then you'll have to take that chance.

Thanks for the reply.

I have had to rethink everything and start over. I will try to post some drawings. Talk about money down the drain.

The way I have the drains now the BO officer said I would need to have a stub stack near my toilets for rodding. He also said something about venting.

I have decided I cant have stub stacks due to aesthetic reasons. I also don't want a stub stack for the reasons you have pointed out, I don't want to rod inside.

The rodding problem:
I have come across NHBC Technical guidance 'Y' Junctions under buildings 5.3/04

My current design made use of Y Junctions so rodding all the way to the toilet was not possible (I had no idea that was even necessary).

From what I have understood from the guidance, if my toilets connect direct to the drain (no branching) there is no need for stub stack or rodding points. So I will do that, connect both ground toilets and kitchen sink with there own 110mm direct to IC.


The venting problem:
I need some help to understand Document H.

Page 7 (1.9) I think claims ground floor toilets can be connected direct to a drain if the depth from floor to invert of drain is less than 1.3m (which mine is). It says nothing about venting this toilet.

I will have an upstairs toilet but this will be vented in the traditional manor with a vent stack going above the eves.

My neighbours pipes will also pass through one of my IC and I can see they have not 1 but 2 vent stacks going trough their roof.

I will vent the kitchen sink and any basin using those anti syphon bottle traps.

Does that mean I dont have to have stub stacks for my ground toilets?

There are other confusing parts of doc H that concerns toilets and venting but Im hoping that's not for ground floor toilets. No lengths are mentioned for the direct connection of ground floor toilets to drains.

 

[Hugh Jaleak]

Basic rules of drainage. There must be a chamber at every change of direction in the drain. (Although rules are relaxed slightly now to allow a bend immediately outside of a chamber.) All sections of the drain must be able to be rodded in the event of a blockage. **** wont run uphill.

If you want the official guidance, there's some light reading for you here. https://www.gov.uk/government/publications/drainage-and-waste-disposal-approved-document-h I'd go with that over the NHBC document personally. I wouldn't worry about the venting of WC's, unlikely you will be doing anything that complicated!

The reason you cannot have a blind connection with rodding access is simply, if that lateral coming from the WC blocks, then you have no way of getting rods or a jetting hose down it without removing the pan, (and you certainly do not want to be trying to jet a blocked line internally!) Not everyone is cautious about what they put down the WC, number of jobs where wipes are the issue but the householder wails 'We dont use wipes'. (Well, you're the only one on the run so they haven't come from anywhere else...)

A ground floor WC should be ok connected directly to the drain, the principle has worked well for years, but modern trends do seem to be towards fitting stub stacks with an AAV, ultimately I'm afraid you'll be governed by what the BCO wants, rather than personal choice, but your proposals to keep the laterals separate, joining the main run at a chamber is the way to go, and hopefully BCO will accept that.

Anti Vac traps are more to prevent syphonage in the waste pipework, once the water enters the 110mm drain then any risk of syphonage is gone, so such traps are not a vital requirement in my estimation, just make sure they have a 76mm water seal. Again, check with BCO to be sure, requirements can differ between 2 Inspectors from the same office...

 

[gummy bears]

Basic rules of drainage. There must be a chamber at every change of direction in the drain. (Although rules are relaxed slightly now to allow a bend immediately outside of a chamber.) All sections of the drain must be able to be rodded in the event of a blockage. **** wont run uphill.

Again, check with BCO to be sure, requirements can differ between 2 Inspectors from the same office...

Thanks for the reply Hugh Jaleak
This is why I have to try and understand doc H in case an inspector says I need a sub stack when I really don't.

Do you think the 3rd drawing complies? I believe having a WC go direct to a drain is found in Doc H page 7. And I believe is possible to unblock everything from the outside. Just the venting I'm not sure if my vent is too far for it to count.

I have also seen something relevant on page 10 of Doc H part 1.30 about ventilated drains. I believe my drain is ventilated due the new upstairs toilet and the neighbours is also ventilated.

 

[Hugh Jaleak]

Cant get the pic big enough to see in great detail, but looks ok to me. Bear in mind any shared drain, (or those from your neighbour) are the Water Co's responsibility, and you will need to liase with them if making any additions or alterations. As long as the head, (highest point) of the drain is vented, then the rest should be ok. AAV's are a relatively new concept, plenty of older properties with drains functioning perfectly well without them, and just a vent where required.

 

[gummy bears]

Cant get the pic big enough to see in great detail, but looks ok to me. Bear in mind any shared drain, (or those from your neighbour) are the Water Co's responsibility, and you will need to liase with them if making any additions or alterations. As long as the head, (highest point) of the drain is vented, then the rest should be ok. AAV's are a relatively new concept, plenty of older properties with drains functioning perfectly well without them, and just a vent where required.

Thanks for the reply Huge Jaleak.
I will send that to the BO that came to the site to double check with him.
Yes I have permission from thames water and have double checked with them that plastic chamber are allowed.

Yes I guess the highest point will be the upstairs toilet and this will have the usual vent above the eaves.

(I think you need to download the pdf and then you can zoom)

 

[Hugh Jaleak]

That worked, thankyou. " ground floor WC's shown, that correct? Could drop the bottom one into the same run on a vertical junction I would think,. to avoid the need for 2 pipes running under the house, other than that, looks ok to me.

 

[gummy bears]

That worked, thankyou. " ground floor WC's shown, that correct? Could drop the bottom one into the same run on a vertical junction I would think,. to avoid the need for 2 pipes running under the house, other than that, looks ok to me.

Thanks for the reply.

You lost me. There are 2 ground toilets show on the plan. The upstairs toilet is not shown, but the pipe that will serve the upstairs toilet is shown on the far right.

I cant combine anything as the building officer said I cant rod properly then. If you look at the middle plan that's what I did and he said I have to modify it. It's the last one I'm proposing to avoid stub stacks I hope.