Adjusting metal soil pipe

Thanks @dilalio.
I don't know why the plastic conversion was added or when. It predates me.
I was wondering if my circumference measurement of the metal pipes provides any indications on which fitting I may be able to use for conversion to plastic?
One further question at this point please, can I use the recip saw (with metal blade) to cut this when I am ready to do so?
Also, it may not have been clear in the pictures but to confirm - the plastic pipe is smaller than a 110mm pipe.

I will try to get some intel from a local plumbing shop too.

Thanks again

 

https://sciencing.com/calculate-diameter-circumference-5130961.html

And you'll need to know the wall thickness of the pipe to get the ID.

 

I've phoned a few local plumbers merchants and had an encouraging response. It went like this "yes, that's a cast iron pipe that we used to have back in the day..."

There suggestion was to use this for the connection to plastic:


I suppose this makes sense as the flaps on the bottom half of the fitting will squeeze into the iron pipe to form a join. It's not having to go over it and hence risking a leak. One of the merchants did say that I contact them once the pipe is cut and measured. They will have the relevant fitting in stock I was told.

I'd like to know your thoughts on this?

With this now solved (I think) can I revisit the following two points please:

Am I okay to secure the pipe using battens etc (to avoid vibrations) and then cut the metal pipe using a metal bladed recip saw?

Secondly, I am unsure on whether I will be able to explain this but here goes!
My cunning plan is to fit a plastic tee on this rubber fitting. The end going up will need to connect to the vent pipe, which is a different size (that's for another day...) but the other end of the tee will be as low as the bottom of the floor joist and point towards the bath. As a reminder, here is a photo from the floor below:



I think I will need to put a small section of pipe into this end of the tee before I fit a connection to receive the toilet waste and 40mm waste. This toilet inlet can be pushed further back towards the back wall so I can easily fit a close coupled toilet. The current inlet is too far away from the wall. Again, here is a reminder:



My question, which fitting do I put in place to receive the toilet pan and a single 40mm waste pipe?

I hope that made sense and thanks again.

 

Not sure of your plan but any room to fit a manifold?
https://www.screwfix.com/p/floplast-sp558g-waste-manifold-grey/22367

 

Ahem!

 

Welcome to the world of concealed pipework

Cast iron in that location is best cut with some careful work with a 4" grinder and a thin cutting blade.
It has to be done in steps... Cutting a tall section off the front, with vertical cuts, as well as horizontal, to give yourself a sort of bomb door that comes away, thus allowing you to get the grinder inside the pipe to then cut away at the back. You start up high, to get all the way through the pipe and then come down in steps to end up with a clean, square cut, where you want it.
Chamfer the inside edges with the grinder and/or a file, to receive the rubber fins of the mcalpine connector without damaging them.
Your bath and basin waste should ideally connect to the vertical stack, separate from the toilet.
You "may" be able to do this inside the floor void AND the existing boxing by coming down the left or right side of the vertical stack and keeping it tight with a spigot elbow into a bossed branch (as shown in one of your previous images).
Or you may need to bulk-out the boxing to allow for connection of the 40mm waste, separate from the wc.
It's hard to tell exactly how to achieve this without being there and having an assortment of fittings to hand to dry plan the setup.
I'd use your local merchants and ask them if you can bring back unused fittings... I do this a lot with my shop.
I'd cut the cast low down, to get the mcalpine fitting in and then come off that with plastic before going into a solvent weld boss connector and then on to a solvent spigot branch... That way, you've dealt with the cast and can then more easily configure the plastic.

 

The surface patern, swaging above the top boss and lack of grainy surface makes me think,its possibly galvanised steel??

 

Yeah. Does look like the railway fencing a bit. Either way, same procedure to get onto it as long as ID is compatible with the mcalpine coupling.

 

@dilalio thanks again!
On the 40mm waste I think you are suggesting that I bend that to run alongside the soil pipe and then turn it into a soil pipe further down. I’ve drawn a crude illustration below



If yes, I think that should be fine but will need at least two 90 degree bends. Is that okay? Particularly the lowest one as water and any other matter will drop vertically into this. I am concerned about blockages

 

I'd still be going with the advice to take it apart at the existing metal to plastic joint and see what you've got. If that is galvanised steel, I have to wonder if the McAlpine connector will be too loose a fit inside the pipe. If it si, then you're looking at a Flexseal coupling, but then I would be concerned would the steel(?) pipe be rigid enough to get a reasonable seal on with a Flexseal.

You may yet end up taking all the current stack down and making a new connection to the drain, and replacing the lot above that point in plastic.

 

I will definitely start with removing the plastic pipe and gauging the pip size. Assuming it all checks out, will I be okay to drop through the 40mm waste with the two 90 degree bends?

 

If you change the soil to plastic further down as suggested above you could then fit a manifold like I linked to which would do away with one bend and less likely to get blockages
You may also get the sink waste into it as well?

 

Aha, yes I can see how that may work. It’s going to be a case of whether the manifold will fit in the existing space. Will definitely give this a go.

Failing this, will two bends be an issue?

Planning on doing this tomorrow

 

Could be either asbestos, pitch fibre..
But it looks like lead..look

https://www.google.com/search?q=lea...egQIARBt&biw=360&bih=518#imgrc=-WQiJncsBmarCM

 

But