Ground floor WC -rodding access

[Steady]

Question re-the above. Going to fit a downstairs WC which will be sited roughly the other side of the wall adjacent to where the short vertical piece of soil pipe is in the first picture.
I don't want to do it as a stub stack (which was the original plan) as I've now got foul waste from a first floor bath and a downstairs shower and basin which will need to run to a vertical stack. There are currently two other toilets towards the back of the house but these already have their own vertical stack which is the other side of a doorway so that stack can't be used to take branch pipes from any of these sanitary appliances.
My plan is to put a new vertical stack in roughly where the bottle trap is in the left of the first picture ( this will be removed and blanked)
Then would take a long rest bend at the foot of the stack and join in at the Y piece where the short vertical stub is currently connected about four feet away. It's a single pipe drainage system and drains out towards the road at the top of the picture.
I was going to fit a soil elbow with access cap where the wc waste first exits the wall and also fit an access pipe on the new vertical stack just above the branch for the new wc.
Reading the relevant government approved document it simply states there has to be rodding access but doesn't go into specifics . any idea if the two access points mentioned will suffice in this example? Or do I need an inspection chamber? Aware that you don't need one for a stub stack, only an access cap as I remember?

 

[Hugh Jaleak]

First issue is, it looks like the whole run is going into a 90 bend at the downstream end? That is very unlikely to be permitted, you will need a chamber there. If invert depth is <600mm then shallow access chamber (225/300mm diameter) can be used. If deeper you'll need the bigger 450mm chamber.

Provided there is a chamber at that end, and a rodding eyes on the WC connections then I dont see a problem. You must use a long radius bend at the foot of the stack, but I'd be reluctant to fit a chamber where that joins the main run, as I suspect spatter on the opposite side could be an issue. Provided the main run can be rodded from the downstream end, and the short section from the stack is accessible from above, at ground level, then it should be fine to me.

I would however, put the proposed ground floor WC on it's own connection, you look like you may fall foul of the 450mm rules, (No connection may be made to a stack within 450mm above the invert of the drain), due to possible blowback caused by compression of the air in the pipe by falling soil from the WC above. If the proposed WC position is the other side of the wall from that short stub, come through the wall and fit an access elbow to connect to that stub. Put the upstairs on the separate stack.

Also, your wastes need to discharge below the grid, but above the level of the water in the gulley. Alternatively, use the back inlet, a bend and a 110mm to 40mm connector.

 

[Steady]

Thanks for the detailed comments and suggestions.
A very good point about that 90 bend at the downstream end. It has been bugging me and No idea why he didn't use 2x 45's there tho' he did put an inspection chamber in next to it (as per below photo) albeit there is an old emulsion bucket there in the photo where there is now an inspection chamber.
Also thanks for reminder about the base of stack 450 mm rule. I'd forgotten about that one!
I'll take some measurements tomorrow.Got a hope I might have enough height from the drain to meet the requirements as any horizontal run from downstairs WC would be fairly short (so not losing much height there) But it could be tight.
The wastes in the picture are just installed temporarily -one is condensate, the other one will be the combined waste for the cloakroom shower and basin. I was going to boss those into one connection on the new stack.
I would happily run this waste to a stub stack but then I've still got a problem with the bath waste which is currently going into a hopper fitted out of shot above the rainwater pipe seen at the top of my first photo.Can't run this bath waste to the existing stack which is towards the rear of the house as it's just too far a run even for 50 mm waste pipe.But I understand it does need to go to a stack and not to a hopper so I need another vertical stack .

 

[Hugh Jaleak]

Not sure what's going on there, but it needs changing. That looks like the upstream end? (Assuming chamber is the right orientation.) Gulley is roddable via the outlet, so can join the main run on a 45° junction, that chamber needs to be on the bend, preferable with a 45° bend either side, so the straight through channel carries the waste.

Likewise the other end, nearest the road as shown in your first pic, must have a chamber on the change of direction, a. its a pinch point for blockages, and secondly, rods wont go round, even a jetting hose may struggle/get stuck.

 

[Steady]

That last photo is the downstream end (in front garden nearest road) and the main plastic run joins into the clay drain just off the bottom of the photo.
The chamber is a 300 mm one with four outlets. Am i best off to put the chamber on the corner where the 90° elbow is present and plug the redundant outlet? so would then have a 45° turn at the corner through the chamber?

 

[Hugh Jaleak]

Yes, put the chamber on the corner, with a 45° bend (single socket type, so spigot into chamber sockets), either end of the main channel. Pic of some drainage a friend did recently, gives you the idea.


Chamber will allow rodding access in both directions then, (this is what the BCO will want to see). The Gulley will be fine connecting on a junction at that point.

 

[Steady]

That's helpful. thanks very much.
BCO incidentally was from a private company( not council) and she's already passed this drainage work. This was only after I flagged up the first effort with her as I wasn't happy with the work -No granular bed was used, fall was not consistent along the run or even adequate in certain areas and normal 87.5 degree Junctions were used instead of 45° Y branches.But the fact that it passed says more about the cosy relationship between the architect and this particular private building control company than it does about the quality of this drainage work, which I still wasn't particularly happy with after they finished. But my experience is you can only squeeze so much improvement in the standard of work out of certain tradespeople before they pack up their tools.Some people just don't deserve to be in the building game. A lesson learned on this one for sure.

 

[Hugh Jaleak]

Building Control, (as far as I'm aware!), is only administered by the Local Councils, simply to ensure the Building regulations (UK Law to ensure safe and habitable Buildings), is complied with, and to prevent people cutting corners. Sadly an example we are all aware of only too well when things slip through the net is the Grenfell Tower tragedy.

You will need a certificate from the Local Authority Building Control to state the work complies with regs, or you'll be asking for one retrospectively if/when you come to sell the house. That's when the fun starts as they may not be willing to pass work they cant see, e.g. drains....

 

[Steady]

My understanding of it may be wrong but I was led to believe that the approved inspector( in lieu of council building control officer) can and does issue the final certificate once building work is completed to their satisfaction.I wasn't given to believe that Building Control themselves would need to further approve the works, given that they have effectively delegated responsibility to an approved inspector in my area.
https://resi.co.uk/advice/building-regulations/approved-inspectors-vs-local-building-control

 

[Hugh Jaleak]

Interesting, I didn't realise some Building Control work had gone out to private companies. Cant see my LA letting that happen, but you never know.

Bottom line is though, work still needs to comply to Building Regs, seems you've been shrewd enough to call it in when you've been unhappy already, and to be honest, if the Builder jacks and walks off after you've pulled them up for obviously substandard work, then you'd probably be better finding someone else anyway. Drains need to be right first time, otherwise you are leaving yourself open to a lifetime of issues, which may only be solved by digging the lot up and starting again.

Been there and done that, sorting pout other peoples bodgejobs, a blockage is inconvenient, getting sewage in the house every time it rains isn't an option.

 

[Steady]

Got some pipes in temp.Excuse the wrong colour pipe.
This arrangement will have rodding access for the main stack through an access pipe indicated on the photo and the ground floor toilet will have a screw down end cap on top of the branch that goes through the wall.
Was considering adding a rodding point coming off another 45° branch cut in to the horizontal run in the trench. Any concerns or suggestions?
Thanks

 

[Hugh Jaleak]

Cant see any evidence of a chamber at that downstream bend in your earlier picture, also wasn't there a gulley connected here?

 

[Steady]

There is no chamber where that branch connects to the main run and i can see it's going to be pretty unlikely to be able to fit one there because of the gas pipe running just above the 45° junction in the close-up picture.That was really the motive for my post in the first place because I knew I needed some rodding access in the absence of a chamber.
There was a gulley where you circled but It was only for one waste pipe which can be bossed into the stack.

 

[Hugh Jaleak]

You have been better then fitting a 45 bend and then a chamber with a 45 downstream at the front, to avoid the gas pipe, rodding points have their uses, but makes a hell of a mess trying to unblock from upstream with a full pipe.


Connect stack into that now redundant gulley connection. Leaving blocked off unused laterals will only confuse matters in future.

 

[Steady]

You recommend putting a chamber in where you've drawn the blue circle?
But ok to keep the arrangement I've currently got With the two toilets going into the main run together?
Or have I misunderstood?
Unfortunately that gas pipe follows the same route all the way down to the road so I'm not sure I'd get an inspection chamber riser in at that downstream 90° corner For the same reason as before. This might be why he didn't bother doing it originally and put the chamber round the corner in front of the house.
The old gully connection which I've blanked off unfortunately can't be used for a connection from the rest bend. I did try this but I can't move the vertical stack far enough to the left to make enough room to throw a bend into the junction. If I move the stack further to the left to try and do this I will be covering the waste hole for the shower pipe ( or be too near to it to boss it in ) or going further to the left I will then be hitting the gas meter box as in photo.
The only way to get into that redundant branch would be to use a knuckle bend at the base of the stack But wouldn’t be too happy about that.