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Discuss Cast downpipe in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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Hi all.

I’ve got three sections of 65mm cast downpipes which are cracked. They are fixed with holdfasts hammed into wooden pegs in the rubble stone wall. Is the replacement of these possible by myself??? It looks straight forward tbh, pry them out from the top down, and replace from the bottom up? I take it you just hammer them back in.

I’m pretty handy, I’m an electrician to trade but can turn my hand to most things 🙈 would anyone strongly advise against me doing it?

Thanks
 
You should be OK, you need all new pipe nails 3" or possible 4" & you would be best to make all new wooden pegs while you are at it.
Main problem you will find is just how good a fixing they are, don't be temped to use the pipe length as a leaver as you will break the ears off.
Have fun!!
 
They are hold fast fixing rather than lugs as per attached pic. I was tempted to reside this section as it is ok just the socket is split on the end, can I cut it off and replace with a loose socket with spigot? Or am I aswell just replacing the length while I’ve got it all off!
 

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You can do either. Personally, I would replace the whole length. If you cut it use a high quality hacksaw blade. It takes a bit longer, is good for your fitness, gives a neater job and avoids getting small bits of swarf / filings on adjacent paintwork - they cause spot rust marks on white paint!!

Never use a grinder on cast iron

Good luck
 
I’ll just replace the hole length. Do I just prise the hammered in clamps out? I’ve read your not supposed to hammer the hook back in as it will bend but I don’t see how else you would hammer them back in?
 
I tap the hook in with a heavy wooden mallet or use a steel hammer onto softwood packing piece between the hammer and the hook.

However, be aware that iron cracks easily if hit with a hammer and also, if left in a stressed (in tension) condition may crack 24 hours later. Thst is all too easy to do with long pipes restrained at either end with hook fastenings - or indeed pipe ears stressed across the two fixings
 
Are you aware of cast lookalike black plastic pipe. It looks like the real thing but much easier to handle ...centralheatking
 
I have done lots of RWP in my time but not seen this, not many buildings in rough stone around here so I guess it is a regional thing.

Just looked at the photos again are they loose sockets or actually part of the pipe length ? it looks like the water is running out all the way round the socket suggesting its a loose socket if so it could just be the rubbers. I seem to remember that you also had to seal the gaps with a mastic & paint over on one of the systems, might just need that.

I would be very interested in more details & photos if you did replace with new Rhys boni.
 
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I have seen the imitation cast plastic pipe but apparently it is just a coating on normal pipe to give the effect. I’d rather keep it cast.

The socket is actually split and when I poked around it it is like a different part that is attached to a staight length, definitely not cast with the length anyway, a loos socket would fit inside the pipe, this is around it and the pipe goes up inside??? So two lengths have cracks around 4 feet long and one has this issue, builing renovated in 1995 and all was replaced then. So much for the 100year lifespan!
 
Check for blockages, only freezing water inside the pipe should cause it to crack, I take it you have the manufacturers details for the replacements?
Seal internal joints this time with mastic but leave vertical sockets unsealed / loose.
 
Pipes successfully installed, only took about an hour. The old pipes the sockets were separate to the length of pipe, water had got in and split the socket. The new stuff seemed to be cast as one.

No blockages so unsure why 2 sections split right up the side.
Hi, I'm one of the "older" plumbers on the forum and being more mature in years has given me the knowledge in how to install lead and cast iron as well as the now widely used modern alternatives. I have had the best of both worlds, with the old and the new.

I was most interested in your post.

There are a few reasons why most cast iron pipe work splits. Cast iron being a metal, corrodes from the inside out, much in the same way that central heating radiators do, because they are not painted on the inside. They have little internal protection. Cast iron has a variable thickness and one side of a pipe, may be marginally thicker or thinner than the other side. If for example rainwater is regularly concentrating its flow on the one side or seam of the pipe, then this is where corrosion is most likely to take place, resulting in a split.

Pipes which have a face touching the wall, especially a stone wall will attract dampness and corrode quicker on that face. This is often because of driving drain being blown against the building.

Cast iron is still a very durable and long lasting pipe material. Here in Scotland, many local authorities specifically specify that the first length of any stack or downpipe at ground level has to be cast iron pipe. This is to prevent breakages, that otherwise may occur with plastic pipe being at ground level, especially in busy street areas.

As part of your annual maintenance schedule, it's important that your cast iron pipes are wire brushed of flaking paint/and or rust and are given two coats of a good quality external black paint. If you maintain this schedule, then cast iron pipes will last for a great many years.
 
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When I ordered the pipe I went for the ready finished black instead of primed only, I’m just wondering how long this factory coating will last. Manufacturer was hargreaves-foundry. Close ups of the cracked pipes
 

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