Drainage help please...

[Mulberry View]

I won't go into lots of detail here, but our foundations c'ock up resulted in some last minute decisions that have had an onward effect. It's not the end of the world, but I just need to figure a couple of details about my foul drainage.

 

This is a rough idea of how I expect my drainage to run. Starting at the top...

 

The first run of pipe after where I've shown the rodding eye is from the Kitchen and that goes in a straight line, approximately 10 metres, to the first chamber, which is there to take the pipe coming in from the internal SVP. This is the short penetration shown and brings in flow from the Master Ensuite and a second Ensuite only.

 

The run then goes into the second chamber, which handles the incoming flow from the main Bathroom (the longer pipe) and Utility room before proceeding towards the mains sewer.

 

 

Firstly, do I need the rodding eye? I'm hoping the first chamber will give sufficient rodding access, being the first point for solids coming in. I'm going to struggle to get a rodding eye in the indicated position as the drainage run will be fairly deep at that point

 

Secondly, am I able to use a swept T-piece under the building? If I can do so, my Utility sink/washing machine etc can follow the red route and take away one of the penetrations. I guess this must be OK, as I'd have needed a T-piece if the rodding eye is required?!

 

 

[saveasteading]

I think you need the rodding eye, and thd extra cost or hassle is presumably small.

I don't like the red option. Keep the flow simple.

 

It's simple really. Imagine a blockage at each (every) point of the system, and make sure you can rod right through it.

[Mulberry View]

2 minutes ago, saveasteading said:

I think you need the rodding eye, and thd extra cost or hassle is presumably small.

I don't like the red option. Keep the flow simple.

 

It's simple really. Imagine a blockage at each (every) point of the system, and make sure you can rod right through it.

 

Yes, I agree in principle.

 

In practical terms, some parts of my drainage are having to be restrospectively placed under the foundations. It's not as bad as it sounds, as my concrete is only about 300-400mm deep, but the ground level where the rodding eye will emerge is a fair bit higher and without much distance before we reach the boundary. Can a rodding point be vertical? The one I did on my last project was 45° and of course I'll need some length for that. It'll mean one more place I've got to go under the foundations, which of course I'm trying to minimise.

 

Presumably there are minimal solids coming in from the Kitchen...

 

 

[saveasteading]

33 minutes ago, Mulberry View said:

rodding point be vertical

Yes. A roddable bend. 45 degrees better and has standard fittings. Or a chamber.

34 minutes ago, Mulberry View said:

minimal solids coming in from the Kitchen...

Don't count on it. And hot oil will soon coagulate. Plus the flow can be slow.

If the run is short then you can remove the U and get a snake along it.

[Mulberry View]

1 hour ago, saveasteading said:

Yes. A roddable bend. 45 degrees better and has standard fittings. Or a chamber.

Don't count on it. And hot oil will soon coagulate. Plus the flow can be slow.

If the run is short then you can remove the U and get a snake along it.

 

Presumably I'd then not be able to fit a rest bend at the Kitchen, but would have to instead use a T-piece with the vertical branch taking the Kitchen flow and the horizontal run continuing out of the building towards the rodding eye? Or is there a swept T-piece designed for this purpose?

[Russell griffiths]

No rodding  eye needed, 

but as a bit of belt n braces

can you bring the 110 up into the kitchen in a cupboard unit and fit a connector to take 50mm from kitchen stuff, on top of this 110 in cupboard you can have a screw cap for emergencies, it will never be needed with today’s jetting equipment. 

 

Dont do the red  line thing. 

Why are you worried about extra pipes coming from the building 

i currently have 9 110mm pipes coming out. 

If you are having block n beam , why are you under the foundation level, would you not be bringing pipes out on top of foundation through your first row of Nudura. 

Obviously I cannot see it but I remember your foundation pics recently. 

Edited November 3, 2022 by Russell griffiths

[Mulberry View]

9 minutes ago, Russell griffiths said:

No rodding  eye needed, 

but as a bit of belt n braces

can you bring the 110 up into the kitchen in a cupboard unit and fit a connector to take 50mm from kitchen stuff, on top of this 110 in cupboard you can have a screw cap for emergencies, it will never be needed with today’s jetting equipment. 

 

Dont do the red  line thing. 

Why are you worried about extra pipes coming from the building 

i currently have 9 110mm pipes coming out. 

If you are having block n beam , why are you under the foundation level, would you not be bringing pipes out on top of foundation through your first row of Nudura. 

Obviously I cannot see it but I remember your foundation pics recently. 

 

The cupboard cap connection situation sounds ideal. I can't see that 110 run ever blocking up before the first chamber, but a 'just in case' solution seems like a good idea. You think BCO will agree with that?

 

Noted on the red line thing.

 

Our foundation c'ock up involved a late change of 'top of concrete' height. I suggested a further 300mm step in the foundations, but my engineer disagreed. Consequently now my foundations are pretty shallow and my soil pipes will be too. The 300mm step I suggested would have prevented this and I cannot see why it wouldn't have worked.

 

To come over the top of the foundations, my pipes would be only about 200-300mm under the topsoil. I don't want to be constantly revealing them in the shrub beds etc, so putting 2-3 of them under the foundations seems like a sensible investment of time and almost unavoidable. My plan would be to trench either side of the concrete strip, then pass under with a long core drill as it'll be through hard chalk. In theory, it doesn't feel like the hardest thing I've ever done.

[Russell griffiths]

Building control are interested in you showing how you an maintain the system. A chamber on the outside gives access to rod or jet backwards, nowhere does it say you need access on both ends of the run, if that was the case every toilet connected to a rest bend would be incorrect and would need to be on a tee with a rodding eye, which doesn’t happen. 

So rest bend up to floor level then boss connection then a cap for maintenance, if you want, but don’t have to. 

 

 

[Mulberry View]

Another thing, because I'm having to come up alongside and/or under the foundations, my vertical pipes will be around 100-150mm off the wall due to the width of the foundation. Presumably I can fit an offset piece to bring it back to the wall after the foundation? The join would take place mostly in the void I guess.

 

I imagine this will involve either a pair of double socket 45°'s, or a double socket 45° followed by a single socket 45°

Edited November 5, 2022 by Mulberry View

[saveasteading]

10 hours ago, Mulberry View said:

either a pair of double socket 45°'s, or a double socket 45° followed by a single socket 45

Sounds ok, just always think of how it will flow and that a rod will get aling it. 2 x 45 together can disrupt flow / catch a drain rod.

A short straight between might help.

Why 45 though?  22 or less might work.

 

[Russell griffiths]

Why do you want the pipe near the wall. 

Go and pick a selection of toilets and download the pdf of dimensions, it will give you the centre dimension for the toilet outlet, you also have a lot of wiggle room with pan connectors these days. 

Also take into account the wall make up, you might have a batten on the wall to take pipes and cables, so allow for that. 

[Mulberry View]

41 minutes ago, Russell griffiths said:

Why do you want the pipe near the wall. 

Go and pick a selection of toilets and download the pdf of dimensions, it will give you the centre dimension for the toilet outlet, you also have a lot of wiggle room with pan connectors these days. 

Also take into account the wall make up, you might have a batten on the wall to take pipes and cables, so allow for that. 

 

Thanks again Russell. So, is it good practice to come up through the floor directly beneath a WC then have the Shower/Basin connect into that pipe? My Architect appears to have drawn it as a pipe in a boxed in section in the corner with the WC coming in from one side and the basin/shower from the other. In which case, getting the pipe as close to the wall as possible would reduce the depth of the void.

 

 

 

There is a 25mm service void in the plan, I assumed I would increase that one wall to be deep enough to house the 110 pipe, perhaps even deep enough to house a concealed cistern and the shower gubbins for the main downstairs bathroom.

 

I do certainly have an SVP that will need to be close to the wall as it just passes through a downstairs room in order to serve the upstairs bathrooms.

[Temp]

Do you need the stack in the corner for other reasons such as an upstairs WC? 

 

It can be tricky to connect a shower into the pipe at a WC.  Especially if it comes up through the floor right where the WC is going. I would consider buying pipe and fittings to do a mock up of the arrangement before you are committed. 

 

The Architects stack in the corner approach allows you to defer thinking about the details a bit but you still need to think how the shower will connect into the stack if you don't want it raised on a plinth. You could also consider running 110mm under the floor to where the basin is going. Otherwise it appears that's also going to mean raising the shower so it can go under the shower to the stack.

 

[Mulberry View]

54 minutes ago, Temp said:

Do you need the stack in the corner for other reasons such as an upstairs WC? 

 

It can be tricky to connect a shower into the pipe at a WC.  Especially if it comes up through the floor right where the WC is going. I would consider buying pipe and fittings to do a mock up of the arrangement before you are committed. 

 

The Architects stack in the corner approach allows you to defer thinking about the details a bit but you still need to think how the shower will connect into the stack if you don't want it raised on a plinth. You could also consider running 110mm under the floor to where the basin is going. Otherwise it appears that's also going to mean raising the shower so it can go under the shower to the stack.

 

 

In that location there is no further need than that one Bathroom. I had already felt that connecting other things where a toilet is would be tricky. I do like the idea of being able to decide precise layout later for that room.

 

SWMBO likes the idea of a recessed 'shelf' in the shower, that would need a fairly deep box-in, so it could easily double up with boxing the pipe in as drawn, along with the concealed cistern.

 

I think I'll go with a simple offset to bring the pipe back in, using the shallowest angles needed for the required offset once measured.

 

Thanks.