Simple job? Don't be silly. Long story short, blocked downpipe [1],
but now need new downpipe. The bottom half is original cast iron, and a
short test length of modern plastic 68mm pipe is a bit loose, say 2 or
3mm. Will that matter? Fall is vertical, and I would prefer to retain
the bottom six feet, which is cast, and just replace the length from
there up to the gutter.

[1] Victorian house, mostly still original cast gutters and other
fittings. Discovered today that one downpipe is original cast iron for
the final six feet, but the eight feet or so above is something I have
never seen before. There is a seam at the rear, and the material is
metal, possibly galvanised, zinc or similar. Quite thin - trying to
remove it, I put my thumb through it.
--
Graeme

On 16/05/2019 18:05, Graeme wrote:

Simple job?Â* Don't be silly.Â* Long story short, blocked downpipe [1],
but now need new downpipe.Â* The bottom half is original cast iron, and a
short test length of modern plastic 68mm pipe is a bit loose, say 2 or
3mm.Â* Will that matter?Â* Fall is vertical, and I would prefer to retain
the bottom six feet, which is cast, and just replace the length from
there up to the gutter.
As long as the top piece goes inside the bottom piece a slight gap can't
matter. If everything else is CI then why not replace this top section
with CI? When I replaced some CI I found that the gaps were quite large
so I locked-up the joint by tapping-in a strip of lead sheet, then
topped-off (flaunched?) the joint with a little mortar to give a run-off.

[1] Victorian house, mostly still original cast gutters and other
fittings.Â* Discovered today that one downpipe is original cast iron for
the final six feet, but the eight feet or so above is something I have
never seen before.Â* There is a seam at the rear, and the material is
metal, possibly galvanised, zinc or similar.Â* Quite thin - trying to
remove it, I put my thumb through it.

On Thursday, 16 May 2019 18:05:40 UTC+1, Graeme wrote:

Simple job? Don't be silly. Long story short, blocked downpipe [1],
but now need new downpipe. The bottom half is original cast iron, and a
short test length of modern plastic 68mm pipe is a bit loose, say 2 or
3mm. Will that matter?

pack the joint with linseed putty.


NT

Fall is vertical, and I would prefer to retain
the bottom six feet, which is cast, and just replace the length from
there up to the gutter.

[1] Victorian house, mostly still original cast gutters and other
fittings. Discovered today that one downpipe is original cast iron for
the final six feet, but the eight feet or so above is something I have
never seen before. There is a seam at the rear, and the material is
metal, possibly galvanised, zinc or similar. Quite thin - trying to
remove it, I put my thumb through it.

In message ,
writes
On 16/05/2019 18:05, Graeme wrote:

The bottom half is original cast iron, and a short test length of
modern plastic 68mm pipe is a bit loose, say 2 or 3mm.

As long as the top piece goes inside the bottom piece a slight gap
can't matter. If everything else is CI then why not replace this top
section with CI? When I replaced some CI I found that the gaps were
quite large so I locked-up the joint by tapping-in a strip of lead
sheet, then topped-off (flaunched?) the joint with a little mortar to
give a run-off.

OK, thanks. Ideally the replacement will be CI, but as the only spare
length to hand (i.e. in the shed) is plastic, that will do for now.
--
Graeme

In message ,
writes
On Thursday, 16 May 2019 18:05:40 UTC+1, Graeme wrote:

The bottom half is original cast iron, and a
short test length of modern plastic 68mm pipe is a bit loose, say 2 or
3mm. Will that matter?

pack the joint with linseed putty.

Sounds good. I was planning to use whatever silicone sealant I can find
in the shed, but am sure I have putty too.
--
Graeme

I'm sure it had a little plaque on it saying fitted by bodgit and run
gutter and plumbing experts.
The worst ones for such things are the square downpipes.

One of the issues is often the different expansion rates of the materials
used, particularly if plastic and cast iron are used. Unless in a
conservation area, I think I'd go with a good quality plastic for all of it.
Much less hassle in the long run even if it does tick on hot days!
Brian

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"Graeme" wrote in message
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Simple job? Don't be silly. Long story short, blocked downpipe [1], but
now need new downpipe. The bottom half is original cast iron, and a short
test length of modern plastic 68mm pipe is a bit loose, say 2 or 3mm.
Will that matter? Fall is vertical, and I would prefer to retain the
bottom six feet, which is cast, and just replace the length from there up
to the gutter.

[1] Victorian house, mostly still original cast gutters and other
fittings. Discovered today that one downpipe is original cast iron for
the final six feet, but the eight feet or so above is something I have
never seen before. There is a seam at the rear, and the material is
metal, possibly galvanised, zinc or similar. Quite thin - trying to
remove it, I put my thumb through it.
--
Graeme

Brian Gaff explained :
I'm sure it had a little plaque on it saying fitted by bodgit and run gutter
and plumbing experts.
The worst ones for such things are the square downpipes.

The worst for what such things Brian?

All of my gutters and fallpipes are square, I have not noticed any
problems particularly since I fitted them around 6 years ago.

On 16/05/2019 18:05, Graeme wrote:

Simple job?Â* Don't be silly.Â* Long story short, blocked downpipe [1],
but now need new downpipe.Â* The bottom half is original cast iron, and a
short test length of modern plastic 68mm pipe is a bit loose, say 2 or
3mm.Â* Will that matter?Â* Fall is vertical, and I would prefer to retain
the bottom six feet, which is cast, and just replace the length from
there up to the gutter.

[1] Victorian house, mostly still original cast gutters and other
fittings.Â* Discovered today that one downpipe is original cast iron for
the final six feet, but the eight feet or so above is something I have
never seen before.Â* There is a seam at the rear, and the material is
metal, possibly galvanised, zinc or similar.Â* Quite thin - trying to
remove it, I put my thumb through it.

Seamed pipe is a post-victorian pre-plastic replacement for cast iron.
Galvanized IIRC. Also found in industrial / farming properties, cheaper
and much lighter than CI so easier to install in longer lengths.

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In message ,
newshound writes

Seamed pipe is a post-victorian pre-plastic replacement for cast iron.
Galvanized IIRC. Also found in industrial / farming properties, cheaper
and much lighter than CI so easier to install in longer lengths.

Thanks for that. Not something I have seen before, and what you say
certainly fits. Now repaired, and waiting for overnight rain to ensure
it all works!
--
Graeme