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!

Indeed however the gasse are heavier than air so if the downpipe fills from ground up it flows into the house pipe too however the access to the inside of the house is blocked via the UBend being filled with water

Good idea thanks

I’ve broken out more of the wall so the pipe is more accessible. The bottom of the copper is maybe 30mm above the floor at the end of the right angle bend and then ramps up to 80mm in only 500mm pipe length by the time it gets in the bathroom!!

Its too stiff to bend now but I’m thinking there is potential for heating it up and reducing the fall or maybe better unsoldering the joint at the end of the right hand bend and connecting there, then new pipe with good/sensible fall the 2m across the bathroom?

any thoughts? Thanks

I'd probably cut it just after the bend and do a new waste at the correct inclination.

Thanks - it will probably have to be un-welded as access to get a good clean cut is tricky…

If you (successfully) cut it at the bend, you’ll still be at 4cm at the end of the pipe.
Does that give you what you need?
A riskier, but ‘better’, alternative would be expose the down pipe more then cut is below the collar with an electric saw. You do not need to cut all the way through to be successful. As it’s brittle, you can get 70% through then snap it off, however cutting 100% (two man job) would be ideal. You’ll want to cut as flat as possible. You might need to expose the bit closest to the wall a bit more.
You could spend an hour or so exposing the the collar a bit more, then decide if it’s worth it. Plenty of YouTube videos available.
Even then, how much more would you gain at the other end?

Hmm I will need to have a think about this again. With 40mm fall on the pipe then there will be about a 150-160mm step up into the shower, which is OK. But it would be good to get it lower. I think I need to get the copper out of the cast iron stack and getting a new connection in there. Not as low as the work you suggest (ie cutting down the top of the cast iron) but a bit less risky... Time to speak to a plumber I think!

I'm a professional plumber and electrician (but not at the same time😀) what you have there is a very typical caulked joint between the iron stack fittings and the copper waste.

The caulk joint is made with a lean mixture of cement (typically 6 parts sand to 1 part cement) - which in theory will chip out easily.

I have removed hundreds of these joints and its not difficult, you simply use a thin 1/2 or 1/4 inch cold chisel and tap away the cement until finally you reach the bottom of the socket and can free the pipe.

However, as you don't want the copper pipe an easier method is to use a pads with a hacksaw blade and cut the copper pipe flush with the cement, then put the pads in vertically and slit the wall of the remaining copper pipe at which point you can roll it in on itself, freeing it from the cement.

If the cement is in tact at that point you can leave it and fit a new section of plastic pipe in the hole with some CT1 to form a seal.

If you get the whole lot out you can simply insert the new plastic pipe and re-make the cement join around it with fresh cement, and that will last forever.

Hope that helps

Ooh thank you! I will have another look at this at the weekend. I might invest in a new/smaller cold chisel as I only have a bulky one which might cause too much damage. Chipping out the cement to free the pipe would be good if I am brave enough!

@DeftWasp sorry - the second method - what sort of saw is a "pads"? thanks

That's auto correct for you, padsaw.

https://www.cromwell.co.uk/shop/hand-tools/saw-blades/steel-padsaw-blade-250mm/p/KEN5975270K?isTax=true&utm_id=22634071325&utm_source=google&utm_medium=cpc&utm_campaign=(GB:Pmax)%20Hand%20Tools&gad_source=1&gad_campaignid=22627906938&gbraid=0AAAAAC4qUT95jl6mK-blT0XAAto-SKSsI&gclid=EAIaIQobChMIi8GnnuHAkgMVTZdQBh0yLyMQEAQYBCABEgLVnPD_BwE

One like the one in the link can have the blade swapped for a standard hacksaw blade for metal

thank you!

@DeftWasp sorry - another question!
if I were to remove the concrete and then later, re-set a new pipe that way - how do I stop the cement dropping into the cast iron? Do I wrap the end of the pipe in something which holds it firm and also stops the mortar falling?

The traditional method (which still works) is to wrap it in hemp rope or alternatively cut a disc of stiff card with a hole that snugly fits over your pipe and outside that sits in the socket.

You will probably find rope under the cement given it's an old installation.

More mulling and I’m keen to try to get the drain lower. @KatiePricesKnickers suggested cutting the collar off - which would be good but I can’t cut away the floor slab to get access for a disk cutter or saw.

how likely is it that the collar has been added/fixed to the pipe rather than being a fully welded assembly? Could I free it without cutting?

Alternatively might it be possible to cut part of the collar away to create a u shape so the waste enters the cast iron drain at a lower level without removing the whole top? I might be able to get a dremel into the space from the bathroom side

First things first - this morning I’ll hopefully be able to remove the copper pipe and maybe will get more clues on next steps…

The collar is an integral part of the casting, so you can't remove it short of angle grinding - and you don't want to totally smash that fitting or you have a bigger job on hand re-making the stack pipe.

Thanks - no. No plans to smash!

i originally had assumed it was all one pipe but then thought I should check.

what about drilling a hole in the (vertical) flat part of the collar to install the waste as a lateral?

The headroom is so tight that I do need to exhaust all options

yep, you could use a hole cutter. cut a hole, then saw down from the top of the collar forming a u shaped notch and sit your plastic waste elbow in there, cementing it in - I've done that before now.

try not to cut or drill through the lower rib/ band of the collar as that gives it strength

Thanks! 🙏🏻 😎🤩

That might be the solution - with even more breaking out…

Loving my new hammer drill/breaker - it’s really earned it’s crust on this flat

Don't use the hammer setting on the cast iron!!

This is turning into the plumbing equivalent on a birthing thread with blow by blow updates!

started chiselling the seal - it’s not weak concrete/mortar - it’s been leaded in…

time for a cuppa and a change of plan!

How big is your bathroom and what shape is it?
While it may not be great looking but could you ramp up the floor from the door swing path to the shower area to give you more room?
You have solid pour floors anyway so with a low profile tray and small tile layout to arrow you to the shower it could look like a quirky design choice?

Thanks I’ll give that a ponder. In the meantime the copper waste pipe has been born and freed from the umbilical cast iron! It was tenaciously hanging in there as it had a flange on the lower lip. Lots of rope seal. I’ll need to make sure to do as good a job when I get it back in there…

If I can go in the side with hole then cut to a U shape the way @DeftWasp suggested and (this is where the hammer drill does come in) make a channel in the floor screed (not touching the structural slab) then I can probably get the tray riser kit to work (75-80mm) which is good as I’ll have access to the shower trap if I ever need it.

Anyone know what drill bit size I’ll need for drilling the waste through the cast iron collar - slightly bigger than 40mm diameter I assume?

44mm?

Why would you put the copper pipe back in there? Surely you'll use modern PVC fittings and then put a PVC fitting into the cast stack and seal around that.