Joining soil of 2 different levels

[sadbaxi]

Hi, I have a new pipe for a downstairs toilet (where it has moved over) joining a manhole.

The height of where the soil pipe emerges from the house cannot be lowered because of pipes and other obstructions on the inside.

In the picture you can see the orange circles indicate where the pipes need to join.

Problem is the height difference between the pipes. It's more than ideal, but not enough to add a bend and drop.

The fall would be about 6-10 degrees which is much more than ideal.

The distance between the 2 pipes is about 75cm.

How should such a drop be connected?

Thanks in advance.

 

[thomp1983]

For a start dig a the soil under the pipe exiting the wall out until your just below the level of the manhole pipe.

With that lot out the way you can probably cut the pipe out the wall back fit a 90 degree with rodding access to make it drop vertical, then a second slow bend to bring it back just above level with the manhole entry. (you may need a small piece of 110mm pipe between the 2 90's to get the levels right).

Then a 45 degree bend or flexy on the manhole entry will probably give you enough of an angle to join to the slow bend.

Ultimately I'd imagine the solution will be fairly obvious once you dig the soil out the way and have clear visibility of the difference in height and space to work in.

 

[sadbaxi]

Thanks for your detailed reply.

Unfortunately if I put 2 90 degrees together to form a drop the level would be too low to join the manhole, even if I took the pipe back to the wall. Even the drop of 1 90 degree would be pushing it.

 

[thomp1983]

You may have to use a couple of these then,

FloPlast Push-Fit 0-90° Double Socket Adjustable Bend Black 110mm - Screwfix

Order online at Screwfix.com. Manufactured from Polypropylene. Not suitable for solvent welding. The use of silicone lubricant on all seals will facilitate jointing. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

If you do use them you really do need to make sure you fit a rodding point of some sort before the first one so it can be cleared from both ends if required

 

[Hugh Jaleak]

Couple of bends might help you, one single socket bend, spigot end into chamber socket, then see what you need on the other end, (adjustable bend if needs must, and section of pipe between the 2 to suit. Cut pipe coming out of the house back as required, (leaving enough to get a connection onto!), I doubt you'll manage with the current geometry.

Drain needs to be protected with concrete at that depth really too.

 

[sadbaxi]

Thank you. So is it ok for the fall to be a bit more than than usual over that short distance?

 

[Ivor Windybottom]

You haven't said what the vertical drop is.

You could use a bendy fitting as already suggested. Alternatively a pair (double socket + socket/spigot) of 45, 30 or 15 degree bends would give progressively lesser drops. There might be numbers somewhere on how much each would be, alternatively just measure them in B&Q, Wickes or wherever.

Don't think there's an issue with a short length of excessive gradient, it will definitely stay clear. Just avoid any long pipes as "stuff" could get left behind.

I'd put whatever botchery you need at the chamber end, to make it most accessible.

 

[Ivor Windybottom]

Just saw it's too high at the top, you need the dip first to get below ground. Would have been better if it was deeper!

You should be able to combine the tip downwards with the corner you also need, do it all in one go. Perhaps a 30 or 45 diagonally followed by a bendy one.

There's also a 45 bendy bend, should be sufficient.

 

[thomp1983]

Can you get an extension for the manhole and maybe sink the base further to give you a decent drop to work with?

 

[sadbaxi]

Thanks for your responses, I had a 45 and an adjustable bend so I tried this morning to see how it would work out.

Sadly I was boxed in by a few things, the depth of the manhole was determined by the clay existing pipe which is not possible to make lower. The soil pipe coming out the house was fixed by the water main and other pipes crossing below the floor level.

I put the adjustable at the wall end before I read your botchery at the manhole end Ivor!! The step will be block paved when it is redone to allow moderately easy access if required to the pipes. The fall on the pipe ended up only being about 5% which is much less than I thought it might end up so I think it will be ok. What do you think?

 

[thomp1983]

Looks like it should work fine, worst case if it blocks at the adjustable joint you'd be able to remove the toilet and rod from there but that shouldn't happen as long as no one put things they shouldn't down the toilet

 

[^woody^]

That's chamber is going to be busy! And hope that flushing one or both of the toilets does not suck the trap out of the gully or other pan.

 

[sadbaxi]

Thanks all for your reply and help.

@^woody^ The gully and upstairs toilet were together before and were fine, so hopefully not. Is there any way to reduce the likelyhood of that happening?

 

[Ivor Windybottom]

I'll give it one of my special "It'll do" approval certificates. I award them to myself now and then!

That one coming down the wall - is it running through the main centre channel and is it the main bathroom, i.e. used frequently?

If so then it will hopefully keep things reasonably tidy. The new loo coming in from the side is likely to leave stuff lying around. Perhaps keep your bog reading library upstairs if you know what I mean.

Is it a 150mm chamber? Just noticed the bulgy fittings.

 

[sadbaxi]

Yes the main bathroom one is the one coming down, it goes into the main centre channel. The current downstairs toilet (which will be decommisioned) is used less frequently I'd say, especially for lengthy reading!!

The chamber is 300mm with slightly adjustable fittings:

https://www.screwfix.com/p/floplast-push-fit-5-inlet-adjustable-mac-chamber-base-300mm/43356