Connecting to new drain

[dunny]

Hi all,

I am connecting to a new drain from a new downstairs bathroom. As the drain comes out of the toilet it will need to turn by 45 degrees, travel 2 metres or so, turn another 45 degrees, travel another couple of metres and then go into a new manhole that is part of the new drainage I have had put in. A couple of questions if I may:-

1. Given that the inside drain will be under a tiled floor once complete do I need to use any special bend (e.g. a bend with a larger radius, a rest bend or something else? I am just concerned that the flow is changing direction and I am not sure what should be fitted.

2. Do I need another manhole at the second bend (outside) as it is chaging direction again or is the fact that it is only a couple of metres from another manhole enough?

3. I can't fit a soli pipe inside the house as the new bathroom is effectively under the stairs. There is a soil pipe on the same drain further up the line - is this enough?

Thanks for any advice.

Regards

D

 

[23vc]

The first bend not being roddable is likely to be an issue, can you not re-route so as to have any change of direction outside the house footprint?
When you say soil pipe assume you mean vent,
if it’s further downstream it’s ok as long as flushing a loo somewhere doesn’t cause a trap to get sucked and lose seal elsewhere.
Diagram may help…

 

[dunny]

 

[dunny]

View attachment 350733

The joint under the stairs is the one I am concerned about I can't reroute it so I don't have any choice but to put a bend in and this will be under the floor under the stairs.

 

[cdbe]

For what they cost (about £30) I would use a long radius bend.

 

[Ivor Windybottom]

I believe 45 degree bends are normally considered OK to be used in this way. YouTube's full of people burying 90 degree corners, which is definitely not a good idea.

For the outdoor one, you could use a Y branch, the pipe from the house joining as the side branch and a rodding point on the continuation of the straight line from your "Manhole"...

You should fit an Air Admittance Valve somewhere reasonably close to the toilet to prevent siphoning.

 

[dunny]

Thanks all, that is really useful.

 

[Hugh Jaleak]

If you must use the 45 bend under the stairs then fit a Chamber outside the building at the second 45º turn. This will give access to the internal run should it ever be needed. I wouldn't want to be running a jet up there towards the Pan but it'll allow for other methods to be employed in the vent it ever blocks.

Other things to bear in mind, as long as there is a vent elsewhere on the property, this run should be fine. Building Regs allow a WC Pan to be directly connected to the drain provided the distance from the invert of the drain to the crown of the WC Trap is less than 1.3m.

 

[Ivor Windybottom]

In reality, with 45 degree bends then if it ever backs up then clearing the chamber that's already there then a few flushes of the toilet will be pretty much guaranteed to clear it.

Ensure all pipes are neatly chamfered and smoothed off at the ends, particularly the cut face and its edges. Any sharp bits are jams just waiting to happen. Saw with a woodsaw nice and straight, then chamfer using a proper tool, then shave the face, inner and outer edges with a Stanley knife held at 90 degrees to it. You should ensure you have a perfectly smooth shiny surface without any sharp edges or bits hanging off.

 

[Ivor Windybottom]

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The tool's good, the lubricant appears to be fairy liquid so I wouldn't recommend it. Use this stuff for chamfering, clean off after smoothing with kitchen roll, then put more on before fitting.

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A 2" paintbrush is much nicer than getting it all over your hands and not being able to grip anything!

 

[Hugh Jaleak]

In reality, with 45 degree bends then if it ever backs up then clearing the chamber that's already there then a few flushes of the toilet will be pretty much guaranteed to clear it.

Not when the drain is stuffed full of wipes/sanitary pad/tampons/plastic applicators/condoms/etc it wont.

If people used Toilets for their intended purpose, instead of a dustbin for anything that they want to get rid of whilst in the bathroom, then there would be far fewer issues with the drainage system!

Air Admittance Valve isn't always required, perfectly acceptable to connect a ground floor WC directly to the drain.

 

[Ivor Windybottom]

Not when the drain is stuffed full of wipes/sanitary pad/tampons/plastic applicators/condoms/etc it wont.

That's why you ensure everything is perfectly smooth on the end of every pipe. That tiny rough edge or bit hanging off is absolutely perfect at hooking onto any horrible thing and becoming the start of a blockage.

If the pipes are all smooth then they shouldn't block in the first place, but if they do then a couple of foot head of water behind it will unblock it.

I've watched various youtube videos of self-proclaimed experts fitting underground pipes. Most just don't seem to care. All the old pipes I've removed here, fitted by professionals, looked like they were cut with an axe, with half an attempt at a chamfer that was probably done with an angle grinder.

 

[noseall]

Hi all,

I am connecting to a new drain from a new downstairs bathroom. As the drain comes out of the toilet it will need to turn by 45 degrees, travel 2 metres or so, turn another 45 degrees, travel another couple of metres and then go into a new manhole that is part of the new drainage I have had put in. A couple of questions if I may:-

1. Given that the inside drain will be under a tiled floor once complete do I need to use any special bend (e.g. a bend with a larger radius, a rest bend or something else? I am just concerned that the flow is changing direction and I am not sure what should be fitted.

2. Do I need another manhole at the second bend (outside) as it is chaging direction again or is the fact that it is only a couple of metres from another manhole enough?

3. I can't fit a soli pipe inside the house as the new bathroom is effectively under the stairs. There is a soil pipe on the same drain further up the line - is this enough?

Thanks for any advice.

Regards

D

Build a new IC more local to the proposed WC.

 

[Hugh Jaleak]

That's why you ensure everything is perfectly smooth on the end of every pipe. That tiny rough edge or bit hanging off is absolutely perfect at hooking onto any horrible thing and becoming the start of a blockage.

If the pipes are all smooth then they shouldn't block in the first place, but if they do then a couple of foot head of water behind it will unblock it.

I've watched various youtube videos of self-proclaimed experts fitting underground pipes. Most just don't seem to care. All the old pipes I've removed here, fitted by professionals, looked like they were cut with an axe, with half an attempt at a chamfer that was probably done with an angle grinder.

The art of Drainlaying has been lost, I agree. Seeing some of the lash up's thrown together by House Bashing crews with no pride in their work, and many are a blockage waiting to happen.

I was shown by Guys that took pride in their work, and what they taught me, has stayed with me. A properly laid drain should never block, but we're not in a perfect world, and so need to cover all eventualities.