Help! Shower waste level trouble - how to adjust this copper to cast iron junction? (Pics)

[bickering]

Any plumbing advice please?

I’m trying to DIY fit my bathroom - taking out a half size bath and installing a big shower 1100x760. It’s not massive but it’s a really small bathroom (probably smaller than many en suites?!)

Anyway in the picture the top of the cast iron drain is roughly floor level and theres a copper connection pipe which turns into the top of it.

The connection is solid but by the time it passes through the wall (300mm (?) away) the underside of the pipe is 80mm above the floor!

By the time i add the fall (40-50mm depending on where I measure from) my shower tray might be 220-250mm off the floor. Making the headroom only 2m which is a bit rubbish.

I spoke to some bathroom fitters who want to charge £5-£7.5k to do the work (on top of fittings)… but this is a tiny room and my budget won’t stretch to that. So I’ll need to go DIY - Ive got the tools and can tackle a lot of things but this connection is new to me - seems like a standard 1960s/70s detail?

If I can release the copper pipe out of the cast iron I was thinking I could use a plastic fitting (as pictured) to save around 50mm of height on the tray… but how to release the copper pipe from the cast iron?

Anyone seen anything similar and have any tips please?

thanks!

I'm having trouble understanding the picture on the left, where did your bath drain connect into this?

Oh sorry. The picture on the left is in a riser (1st floor flat). The bathroom is behind the wall on the right of the picture. The green copper pipe in the pic above comes from the bathroom, through the wall and turns down into a cast iron stack. Theres concrete around the connection to seal it (?).

This pic shows the other side of the wall in the bathroom. The big pipe is for the loo. The end of the copper pipe sits behind/below that to the right of the measuring tape

And this pic just to the right showing how the pipes all come through the wall and project about half a metre into the bathroom

And the original pic zoomed out a bit

If it’s copper then getting it hot enough to flex would move it but I’m not sure how safe that would be as you’ve probably in blow torch territory…

Good thought - but if I bend the end down the drain will have to run uphill 🤣 Although I’ll maybe think about the blow torch idea after Ive broken out a bit of the wall/made it looser…

Think you might have to drill that out.
Is that a Fernco you are going to use?

Yeah. I've done a lot of DIY and plumbing and I'd not be touching that. You'll have no fall, which will cause horrible issues down the line. I'd be getting someone in to sort out the cast iron junction, unfortunately I think it will be expensive.

I can see two risks: one that you crack the cast iron bit trying to get the copper out, the other is that if you succeed you won't get a part which is the right dimension to make a seal.

In a house I might just get my angle grinder out and have a go, but in a flat there is a risk you end up damaging someone else's property and that could turn out way more expensive than getting a plumber out to sort out just that junction.

It is McAlpine:
https://mcalpineplumbing.com/plastic-chrome-fittings/drain-connectors/drain-connector-with-boss/

But I will have a look at Fernco- thanks

Thanks - I will make sure to have a fall.

The problem is that this existing connection has an 80mm rise/fall (depending on which way you look at it!) in only 300mm... which causes a whole lot of other problems.

So if it is expensive to fix and I have to get a plumber than I am OK with that - I just can't afford to get someone to fit the whole bathroom.

Part of the problem is that so far I haven't come across a tradesperson with a good idea of what to do...

When discussing the work with 3 different bathroom fitters. One said they would want to go downstairs and cut out the whole stack/replace with PVC = no thanks! One said they would leave it alone = will do this if it is absolutely the last resort. The third said it might be possible to remove the connections and make a new/lower one but they weren't sure and would worry about cracking the cast iron and was non-committal.

So it is not necessarily an everyday problem but if I can find a solution I don't mind if the fix is via DIY or plumber

I know.... the flat thing adds a certain jeapardy!

On the plus side this cast iron drainpipe is the top of a stack with nothing coming in from above. But on the other hand I don't want anything to fall into the pipe and cause a blockage - so I was thinking that any breaking would have to be by small handtools/cold chisel and a vaccum.

I also won't attempt anything until I have found parts which I think will work with the dimensions.

Thanks for the Fernco link - just realised that an alternative would be to break out the wall but leave the copper in place and cut it back close to the riser - and then add a rubber connector. This would mean that the connection would be lower down than using a regular PVC connector on the straight run inside the bathroom!?

if you've got that much of a fall you should be able to break the wall and just change the angle on the copper, it should be flexible enough. Just make sure the fall is 2cm per meter everywhere.

@bickering Can you post a picture and maybe put some masking tape or something to show where you are thinking of cutting to attach the Fernco?

I think your suggestion is a good one actually. If you can get the fall without touching the cast iron that would be good especially if that copper - cast iron connection is sound. It looks dry anyway.
If you have a city plumbing near you I think they do Fernco,s so you could go and have a look at them and I would also show the staff some photos of what you are trying to achieve. Depends who you get but some are very helpful.

I would not use an angle grinder in a confined space, the risk of kickback is too great. I hate the things in any case. Much less risk with hand tools, sure its slower but you have more control.
I have used a couple of Ferncos,s in very awkward situations and they have been a life saver, they are very good.
Just used a small Fernco coupling from Screwfix on an old lead pipe outlet to meet a plastic bath connection, worked a treat. All replaced now but it was a great emergency solution to my daughters pipe leak which needed doing ASAP.
Also Screwfix forum has a good plumbing section, plus DIY.NOT has a good forum as well.

I don't understand how your bath was draining if you don't have enough fall. Was the bath mounted quite high?

Are you sure that 'riser' is iron and not clay?
What happens below floor level? Does the smaller riser join into the soil stack?
Is the floor concrete?

For that water stack / drain pipe so what are the internal and external diameters (you'll need to get a decent connection). Maybe 2.5 inch internal diameter cast downpipe? It looks like it has a rounded end for a socket connection that the copper has been stuffed into and then sealed with cement so I wonder if a standard downpipe but fitted internally.

It shouldn't be too bad to carefully drill out the cement to leave the socket clear for an alternate fixing. I'm just not convinced you'll get any lower with an alternate fixing that that copper today.

I think the contractor that said look at replacing that pipe with PVC is probably the 'right' answer. But then you are into freeholder territory because it is outside of your flat.

You could shorten that stack under the floor to then join to modern PVC with enough fall. But getting to it to cut cleanly, without breaking, for a PVC join might not be possible.

What about a new PVC run into a boss fitting into the soil stack? More risk of leakage with that approach though.

Thank you - very reassuring.
I think I’ll have another go at the weekend and can then post an update with the wall broken open. Hopefully I’ll have a better idea of where I can get access to cut and what that means for the levels…

Thanks for all your good questions.

The floor is concrete and the top of the cast iron riser pipe is roughly at slab level. There’s another 50mm of screed plus the ex copper pipe slopes up so it’s 80mm above top of screed by the time it’s in the bathroom! So that bit had a huge fall…

The bathroom i took out was really badly installed. I think there was either no fall or the bathroom/sink combined waste ran uphill 🙄

Im going to open up the bathroom wall at the weekend and get a better look - but a PP suggested a Firmco rubber connector and if I can install that on the copper close to the top of the stack (without disturbing the concrete) then I think that’s likely to be fairly easy to do and low risk of damage…. But I’ll open up and see if I can work out how to cut the pipe….

wish me luck!

This is an image of the Firmco which might fix to the copper if I can cut it inside the riser

The down pipe
Is it into a water only drain system or is it at any stage connected to a toilet system?
If there is any chance it links to a foul water drain you need a U bend to stop sewer fumes.

Can you run a new pipe down the outside wall and connect the new pipe directly into the ground drain?
How much "free" space is there between all the pipe?
Is there a clearout point at ground level?

I think iron would eat the copper if left in direct contact with each other so there could be a buffer material on the end of the copper plus something was needed to stop a gravity drop of the cement.

If I want to try move the copper pipe i would scrape back the top of the material between the cast iron and the copper then polish the patina off the copper with sandpaper and steel wool
Aim to see if it is soldered in and what type of cement was used to bed the copper in the "reduced" iron pipe.
I would get a very small chisel and see if I could chip away the cement fill nearest the copper pipe

Cut the pipe highish (depth of plier head) then using heat mats and a blowtorch to heat the pipe and see if a plier will wiggle it and/or a small needle nose plier to kink the pipe circle into a packman shape

Good points - thanks!

It must link to the foul drains somehow but I am wondering if there is already a trap somewhere below my flat. There has been zero problem with sewer gas since I stripped out the bathroom and left the end of the pipe open....

No external wall or drain options available unfortunately

From googling there is probably a seal of hemp/bitumen/something else under the concrete. I would rather not touch that!

Interesting idea about the heating/bending. I will open up the wall at the weekend and see what I can find. I have ordered a few different shaped Firmco rubber connectors (straight/45 deg/90deg) to see if any might work to help lower the level of the pipe in the bathroom, and therefore allow the shower tray to drop to a reasonable level... what fun!

The toilets "should" flush all the way to the processing plant so should not have a build up gas.

Its only if there was a local (part) blockage and the fumes build up to above your pipe

Anyway enjoy your big dig😁

The gas is usually released via a Soil Vent Pipe - where the soil pipe sticks out above roof level. Prevents noxious gas build up indoors. The main soil pipe goes up to the roof - it’s interesting that the copper is head of stack with no vent…

big dig 🤣🤣

Before you go at the wall, I’d drill out that triangular fillet of cement between the copper pipe and the wall.
You don’t want hammer blows to be transferred to the cast collar.