New soil stack - not as easy as I thought...

[ChrisKingston]

I've made a new first-floor bathroom with a toilet on a wall over the side passage. The main combined rainwater/sewage drain runs under the middle of the side passage. So I thought it would be easy to make a new soil stack into the existing drain. But now I think it's quite hard, access is too tight for an inspection chamber or even a rest bend.

I've dug down to find the old clay pipe (about 135mm diameter), and checked this is the pipe that goes into my main drain (inspection chamber about 6m away):

But that hole is about as wide as it can get without undermining foundations or going over boundary. The top of the pipe is about 450mm below the surface at this point.

There is not space for an inspection chamber join, and no space for an underground rest bend, so my idea is to make a 92.5 bend in the black plastic above ground then run it in from a short height at 45 degrees. This is my design so far (with an additional join in from a new ground floor toilet):

What do you think? Could this work? The hole looks just big enough to get a small angle grinder down to cut the old clay pipe, but then all my foul and rain water drainage is out of action til I can repair it.

I'm really stuck with this one and no local drainage firms seem keen, haven't even got a quote yet. I would rather not take this on myself but have a baby due next month so really need to get this bathroom working, so any advice would be great.

 

[blup]

Put in the adaptor underground first, if all is lined up you can continue above ground, if it goes wrong at any stage you can reinstate drainage relatively easily. Good luck (with everything!)

Blup

 

[ChrisKingston]

The only other option would be to try to squeeze a small inspection chamber in, but it's really tight. Then I could have a more conventional underground rest bend at bottom of the new stack, like this:

Is it ok to have a 45bend right out of the chamber?

My other worry about this option is that I would have to dig out what might be the edge of the house foundations. It's an old and fairly solid house but taking an SDS to the foundations doesn't seem like great idea. How do people normally get round this to run a soil stack down next to a wall?

 

[denso13]

Do you have LA building control involved? You should have, and they might have a preference.

 

[ChrisKingston]

I worry LABC won't like any of the options and I'm really short on time! Want to do it so it won't leak and has some access but not bothered about full BC sign off. I am sure that it is my drain not water company though, it only serves my property and is fully within boundary.

 

[blup]

It is a risk not involving labc but it is your call. There are at least three specialists on here who would know, Andy at Herts drainage, hugealec , ianh (who doesn’t post much) and someone called noseall

Blup

 

[denso13]

I worry LABC won't like any of the options and I'm really short on time!

If you are doing it illegally just do whatever is simplest. No one is checking it anyway.

You may regret not getting it signed of in years to come. Up to you though.

 

[ChrisKingston]

I want to do a good job, and not flood the house with poo, or undermine its foundations, or have to dig it all up for a routine blockage. But regs are very inflexible and my council is very slow and expensive to consider things (think 400+ quid for a new drain connection).

 

[blup]

If you are confident about cutting the clay pipe, joining it with plastic, and bedding it correctly with the right fall, do you need a rodding eye? Just make sure nothing goes down the toilet that shouldn't like baby wipes. If there is a blockage you should be able to jet it or rod it. As for selling, if you sell in 20 years I doubt anyone would see it as an issue if all is working as it should be. Or you could regularise it in due course.

Blup

 

[denso13]

But regs are very inflexible and my council is very slow and expensive to consider things (think 400+ quid for a new drain connection).

I honestly hear what you are saying.

But.....there is more to fitting a new bathroom than drainage, such as ventilation, air extract, electrics, access etc., etc. I don't think that places such as this can do anything other than advise how to do things correctly.

I could say that other people play by the rules every day. Sometimes it isn't easy but that's the way it goes. Again, it is an easy way out but it could come back to haunt you further down the line.

 

[Hugh Jaleak]

What is the other pipe visible to the left of your picture? You need to be 110% sure you are connecting to the right sewer, cross connections can and will be traced and the Water Co will make you put it right at your own expense.

Secondly, what is upstream of the point where you propose to connect? A direct connection into the drain may be your best option, i.e. bring the stack down the wall and use a slow radius bend to kick it over to the the junction on the main run. It's not going to be ideal but may be your only option. Fit a Rodding Access at ground level, before the pipe goes under the floor, gives you access up and down the stack then.

Forget any idea of connection another branch in on the same pipe though, (looking at your first sketch there is a horizontal pipe mentioned),, if you want to bring another branch in, do it on a separate connection.

 

[ChrisKingston]

Thanks Hugh for those:

I don't know what that second pipe is, looks like another old clay drain. But I am sure the one in middle of my hole is the main sewer drain for this house. I put rods down from inspection chamber and got someone to waggle a corkscrew while I had my head down hole. I could clearly hear it scratching inside the middle pipe.

Upstream as in further from sewer? That's is other drain and rainwater connections, with some vented downpipes. Or if you mean upstream as in closer to sewer then it's a straight 6m to an inspection chamber which is then next to the main drain.

And yes I think I am abandoning idea of getting a second downstairs loo into the same thing. Just doing the new soil stack would be a win.

 

[ChrisKingston]

A direct connection into the drain may be your best option, i.e. bring the stack down the wall and use a slow radius bend to kick it over to the the junction on the main run. It's not going to be ideal but may be your only option. Fit a Rodding Access at ground level, before the pipe goes under the floor, gives you access up and down the stack then.

I can't quite picture this, you mean run another whole 110mm underground pipe the 6-7m to the main drain? That would be a lot of digging!

Do you have a view on inspection chamber Vs the first sketch?

First sketch was effectively putting a well supported 92.5 bend in black overground plastic to take the main force of fall, then branch it into existing drain with a shortish 45 degree section with rodding access from top. Is the 45 degree section a no-no?

I have bought a small inspection chamber to see the size and think it would be really tight size wise, and would involve a lot of hacking at old brickwork. Is that normal when fitting a new soil stack against the wall?

 

[ChrisKingston]

If you are confident about cutting the clay pipe, joining it with plastic, and bedding it correctly with the right fall, do you need a rodding eye? Just make sure nothing goes down the toilet that shouldn't like baby wipes. If there is a blockage you should be able to jet it or rod it. As for selling, if you sell in 20 years I doubt anyone would see it as an issue if all is working as it should be. Or you could regularise it in due course.

Blup

I wouldn't say confident, I've never done it before! And the access is pretty bad, that hole in pic is about limit of it. I have a small angle grinder with diamond blade (like for tiles), and I might buy a diamond stone blade for multitool.

The only other thing is the collars to grip the old clay go up to 136mm and from my rough measurements, that old pipe is about 135-140mm. Do you ever find that the old pipes are too big for the collars?

The rodding eye as far as I can see is just fitting a triple junction and rodding cap instead of a 135 bend, so it's very little extra work or cash.

 

[blup]

You will need to measure the clay pipe as accurately as possible, buy the adapter and measure that for comparison.

Blup