Cutting cast iron soil pipe.

[timmy74]

Right sorry to bump this back to the top BUT who would take a gamble on just cutting a three foot section out of the bottom half of the stack and replacing it with plastic. At the most theres 2-3 meters of cast iron in the bottom half of the stack, the top half including upstairs loo etc is in plastic?

Howay then what you reckon.

 

[hi-spec plumbing heating]

might as well replace all 3m

 

[Bahco]

However much of the pipe you replace is irrevalent as you will still have to cut the blooming thing

 

[timmy74]

might as well replace all 3m

The trouble is its going through a flat roof and the customer is going to have to get a roofer to reseal it, so i thought if i could get away with cutting a little bit out then the roof would not be disturbed.

 

[hi-spec plumbing heating]

look better in the long run than all bits and pieces

 

[Symptoms]

Timmy - let's get this straight ... you want to end-up with: cast iron out of the ground, a plastic branch, cast iron up through the flat roof, plastic rest of the way? The bottom half of all this is internal? If this is the correct you'll have a hell of a job 'slipping-in' the plastic branch between 2 fixed CI pipes. It'll be easier to do it all in plastic.

Having said that I did a job similar to this years & years ago outside a third floor - imagine cutting into cast iron (WITH A HACKSAW - none of your mamby-pamby angle-grinders then) - at the top of a treble ladder. The pipes remained spike-fixed to the wall, a correctly measured section removed and a reclamation yard CI branch was slipped in. Wet hemp rope in gap followed by hot lead to seal, remember all at the top of the swaying ladder! Why bother I hear you ask? Conversion of listed building into 3 flat so couldn't remove the CI

 

[kjharry]

The cast cutter you showed from hss is the way to go,not easy to use till you are used to it,you will need at least an inch clearance around the pipe for the chain cutter to wrap around.You wrap the chain around,each link has lugs that drop into recievers,then you ratchet with the long handle till the chain is just gripping,then run the chain back and forth till its run a mark all round the pipe,you only need to go around about a quarter of a turn as each cutter is about 2" apart so they overlap as you rotate.Then tighten up the chain,one click only,patience will be rewarded,same again with rotating and tightening one click till the the pipe goes with a bang,which is quite alarming if you havent done it before.You will need to cut again obviously,to get your section of pipe out.I would then use a "Timesaver" cast branch to slot straight in,they fix with 2 part cast clamps and a rubber gasket,not too pretty but better than a mix of cast/plastic,though the clamps will fit onto 110mm plastic if you wish to run plastic from the branch to whatever.You say there is no collar visible to join to at ground level,when you cut the soil pipe low to the ground from experience,chances are you will see a collar not too far below the surface which you could cut around and use if you feel the need.