Cast iron downpipe

[Oldcellar]

Hi all, my house has original cast iron rainwater goods. Generally they are in pretty good condition with the exception of one joint on the downpipe, hopefully there are two pictures attached. It was previously nearly covered by soil that I have moved back from the house. Is this type of failure common? I do have a lingering doubt that perhaps a blockage caused the water to back up and breach the joint. The pipe seems ok where i removed the soil but goes straight down before (hopefully) joining the sewer in the street. I could get a cctv drain survey but was quoted 175+VAT - is this worth it considering the vegetation that was previously there?

Secondly in terms of repair I could use this https://www.rainclear.co.uk/65mm-2-cast-iron-loose-socket-with-ears-black.html in a like for like replacement. However I dont want to have to remove the section of pipe above to put this in. I have seen weatherproof tape to repair this but would this look terrible, what are peoples experiences of these? Any other method of repair to avoid disturbing the rest of the downpipe?

Thanks in advance - great forum

 

[Feltwell]

Hello!

It’s a bit difficult to see from your picture what is below, but that looks like it might be an old repair that has failed to me.

Cast iron pipes can be cut in situ with a grinder, and it is awkward but possible to introduce a new section with care.

The most comprehensive range by far of fittings is from Longbottom foundry - google them and call them for a catalogue, it’s an old fashioned business. The other one worth mentioning is St Gobain do a downpipe socket with a spigot - great for repairs, as it’s often the socket that goes.

 

[Feltwell]

https://www.hambakerrainwater.co.uk...pes-bends-sockets-hoppers-fittings/a586-loose

This is the fitting I meant - if your pipes will come apart, replacing the top socket in your picture with this may be possible.

Edit - Oops, it’s the same as the fitting you originally linked to! :? On dodgy mobile signal at the mo and your link wouldn’t open for me earlier, apologies!

Never fill the sockets - keeping them free greatly eases future disassembly and indicates if you have a pipe blockage. 3 little bits of roofing lead tapped into the joint stops any rattling and stops the 2 iron sections welding themselves together with corrosion.

I suspect that with very careful use of an angle grinder that top socket in your picture could be cut off and replaced with the loose socket above by introducing it carefully at an angle.- without disturbing the pipes above. You may need to slip a small section of plain pipe over the spigot, if that makes sense!

 

[Oldcellar]

Thanks for the reply! I don't actually have an angle grinder, is a hacksaw plus elbow grease a possibility? When you say put a piece of plain pipe over the spigot do you mean use the angle grinder to cut off the old socket and part of the above pipe to create the angle, then use a small section of pipe to cover any gap?

Thanks for the tip with re lead. Makes sense - at the front of the join there is the remains of the old spigot well and truly corroded into place.

 

[Feltwell]

I’d definitely forget trying to cut cast iron with a hacksaw- you’d be there for a very, very long time. Angle grinders aren’t expensive, £20-&30 for a cheapie from Screwfix would do the job.

The spigot on the bottom of the loose socket fitting is designed to go inside a main section of pipe. That pipe is then to go inside the socket of the bottom fitting. So you could put the spigot straight into the socket, but it would be a very loose fit. Putting a bit of cut pipe over it will tighten the fit up, if that makes sense. Not essential though.

You’ll need to go very carefully with an angle grinder, and be prepared that cast iron is brittle stuff and this could turn into a bigger job!

 

[noj]

Looking at the pics it appears that the collar is floating, rather than attatched to the downpipe above, so it could simply be a case of breaking its ears off, or drilling out the pipe nails and it might wriggle off to be replaced by the loose socket. If there's no enough play to get it out (typically the way) you'd need to break it up. Without an angle grinder, a cautious whack with a lump hammer should hopefully crack it without breaking the pipe inside.

The issue then would be if there's enough space to get the loose socket in. If not then you would have to cut a little from the bottom of the downpipe and that would need a power tool.

The problem with cutting in-situ with an angle grinder is that you need a big enough cutting disc to reach the back of the pipe (and cheapie ones are too small). It is possible though to make clean cuts through cast iron using a cheap reciprocating saw and a carbide grit blade - I was doing that last week - plus you don't get all the sparks and flying bits of melted metal.