Advice for removing cast iron soil pipe from wall

[BennyC]

In a few weekends time I'm moving a soil pipe 2-3 inches to the left as part of a bathroom refurb/refit to buy space for a vanity unit. There is no more room than this so it can't be moved any further or on to a different wall.

Removing the stack outside is straight forward enough, i've researched this and have it covered.

The issue I have is how to remove the section of pipe between the toilet and the branch on the outside, this goes through two courses of brick.

I intend to make a jig and fix this to the wall to core out the new section, which overlaps the old and to help keep it centred until it has enough purchase but I'm fairly certain I can't just use a core bit with the old pipe still in situ.

I'm prepared to drill around it/down the sides through both courses and to potentially tap it out but with cast iron having a tendency to become brittle is there a better approach?

Of course soil pipes don't tend to be moved just a few inches so I expect the norm is to leave it in place, cut if flush and then make it good on either side but this isn't an option unfortunately.

Advice and experiences welcomed!

 

[BennyC]

How's the current cast iron one air/water tight to the outside wall, is there a bunch of render which can be attacked with a kango to give you enough play to slide it out?

Not sure, it might come free with a bit of encouragement once the branch is removed/cut but I won't know until attempting it.

The pipe going through the wall will be lead won't it? most people would cut out the cast iron and convert it to plastic just around where the soil pipe exits the wall.

The issue is, what's there is incredibly unsightly... some class use of a braided hose here too...

Essentially what the O/H wants is a clean/tidy straight pipe from the back of the toilet out the wall. The collar of the branch there means the existing toilet is about 2 inches off the wall.

Once complete the toilet will move back and left 2-3". Doesn't seem like much but it creates enough room for the wash stand she wants.

 

[BennyC]

Thanks guys, I have an SDS with chisel/breaker attachments so will sacrifice a few bricks if it won't come out willingly.

I'll report back out of interest in a few weeks.

 

[BennyC]

Planning to use a recip saw for the most part to cut it in to sections. Invested in a carbide tooth blade and some cutting oil for longevity.

I'll let you know what we can sell it for rather than giving it to local skip scouts for free!

 

[BennyC]

Update.

Great success. Minimal swearing. Stack completely removed today. Pictures and process to follow.

One problem in that the adapter for the cast iron pipe to take it to 110mm doesn’t fit! (Screwfix 4255V).

If I remove the rubber collar it’s close but it’s probably 2mm too big.

The internal diameter of this Cast iron pipe is 95mm hence being 5mm too snug as intended to take 100mm to 110mm.

Before I attempt to modify it, any suggestions or alternative couplings I could use?

 

[BennyC]

I used a recip saw with a carbide tooth blade for the first cut at the floor. I was sceptical a 4" grinder with basic Bosch metal disc would do much but to my surprise it was actually quicker and didn't really spark at all and took the lions share of the cutting around the branch which was particularly thick. Chopped the heads off any lugs holding the brackets in the walls which wouldn't pull out easily.

This piece I rocked back and forth to remove from the wall and you can see where a section broke off. Otherwise everything came out in one piece.

I left my self with this to cut off at the branch.

To finally set it free, as I couldn't cut through the bottom of the branch (saw blade was dead and grinder wouldn't reach) a few taps with a mallet and a masonry chisel in the cut I'd made and it popped off.

So then, inside... the extraction begun. Pretty much just used an SDS with chisel/breaker bits and then a 450mm x 8 mm drill bit to get down the sides to start to free it.

Then some gentle Russian persuasion with the mallet (being careful not to break it) and it started to come forwards out the wall.

So you can see the original placement vs where it will be refitted as far left as possible.

A daft amount of work but the original pipe was very unsightly and my O/H does need the extra space gained to fit her washstand in.