Hi All,

We moved into a 70's house last year.
The ground floor is solid concrete with a bitumen
layer and a top surface of wooden parquet.
When we moved into the house we had an issue
with one of the underfloor pipes leaking.
I dug up the concrete floor, replaced the weeping joint
and (foolishly) re-concreted back over the new joint.
We have noticed recently that the adjacent wall was
starting to look damp. I dug up the floor
again and found another area of copper pipe that
appeared to be leaking.
How common is it to have 30 year old pipes leak
inside concrete?
If the situation becomes worse I may dispense with
the underfloor pipes altogether and drop down in room
corners from above.
Has anybody else any experience with similar situations.
Is it comon for copper to be corroded by concrete?

Thanks,
Matthew

"Matthew" wrote in message
oups.com...
Hi All,

We moved into a 70's house last year.
The ground floor is solid concrete with a bitumen
layer and a top surface of wooden parquet.
When we moved into the house we had an issue
with one of the underfloor pipes leaking.
I dug up the concrete floor, replaced the weeping joint
and (foolishly) re-concreted back over the new joint.
We have noticed recently that the adjacent wall was
starting to look damp. I dug up the floor
again and found another area of copper pipe that
appeared to be leaking.
How common is it to have 30 year old pipes leak
inside concrete?
If the situation becomes worse I may dispense with
the underfloor pipes altogether and drop down in room
corners from above.
Has anybody else any experience with similar situations.
Is it comon for copper to be corroded by concrete?



In short the concrete eats the copper. Denso tape is what you need but have
a look at these 2 recent similar threads:

http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/c6ca3754f277cd44/4563c6cb434e000e?lnk=st&q=%22gas+supply+pipe%22&rn um=3&hl=en#4563c6cb434e000e

http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/88d941cba6c68bf0/eaf26b9989ba07a5?lnk=st&q=%22copper+pipes+under+co ncrete+floor%22&rnum=1&hl=en#eaf26b9989ba07a5

Matthew wrote:
Is it comon for copper to be corroded by concrete?

It'll either corrode, or wear through due to movement caused
by thermal expansion of an unprotected pipe. The bitumen
under the parquet floor is adhesive.

Matthew wrote:
Hi All,

How common is it to have 30 year old pipes leak
inside concrete?

I'd say it was almost guaranteed.

On Wed, 15 Feb 2006 12:00:34 +0000, The Natural Philosopher
wrote:

Matthew wrote:
Hi All,

How common is it to have 30 year old pipes leak
inside concrete?

I'd say it was almost guaranteed.

Oh buggeration. This adds another job to the ever increasing list of
things I must sort out before I can actually crack on with the plumbing
in my kitchen (and get the luxury of an actual working kitchen sink
back).

The 3/4" copper pipes between my kitchen and downstairs bathroom would
have been laid some time in the 1970's I reckon. It looks like I will
mostly be digging up the concrete floor and laying new plastic pipes
this weekend then. Blimmin' marvelous.
--
Chris Cowley

Chris Cowley wrote:
On Wed, 15 Feb 2006 12:00:34 +0000, The Natural Philosopher
wrote:

Matthew wrote:
Hi All,
How common is it to have 30 year old pipes leak
inside concrete?
I'd say it was almost guaranteed.

Oh buggeration. This adds another job to the ever increasing list of
things I must sort out before I can actually crack on with the plumbing
in my kitchen (and get the luxury of an actual working kitchen sink
back).

The 3/4" copper pipes between my kitchen and downstairs bathroom would
have been laid some time in the 1970's I reckon. It looks like I will
mostly be digging up the concrete floor and laying new plastic pipes
this weekend then. Blimmin' marvelous.

I would not bother to remove the old pipes.

Just trace em and re-route alongside.

Or re plumb the entire house.

Its been note that houses get a makeover every 15 years or so, a major
refit every thirty, and a gut and replace every sixty...

However7 0's built houses seem to need the gut and replace after 30 years...

Christian McArdle wrote:
How common is it to have 30 year old pipes leak
inside concrete?


30 year old copper buried direct in concrete with no corrosion protection
can be expected to be suffering general failure by now.


For interest, does anybody know the prognosis with stainless-steel pipes
in the same situation? My house was built during a copper shortage in
1973, and is plumbed throughout with SS. I know that quite a few houses
on the estate suffered from leaking concrete-buried pipes early on, but
mine seems to have escaped that. Should I be anticpating a failure now?

The pipework is real SS, not some ersatz plated stuff, but the joints
are all copper yorkshires where visible, so I assume there is at least a
minimal amount of buried copper. There's no evidence of wrappings of any
sort where the pipes emerge from the concrete floor.

The system originally open vented, but was converted to pressurised when
the boiler was moved to the loft. This comforts me because if the worst
happens then I'll get notification from the pressure gauge and the
amount of water which gets pumped into the fabric of the house will be
minimsed. On the other hand, the pressure (pressure vessel plus
hydrostatic) at ground level is higher now than when it was open-vented.
So far, the pressure-loss/time is effectively zero.

Cheers,

Simon.

The 3/4" copper pipes between my kitchen and downstairs bathroom would
have been laid some time in the 1970's I reckon.

The worst thing is that due to the 1970s copper shortage, your copper tube
might be half the British Standard thickness.

Christian.

On Wed, 15 Feb 2006 12:55:17 +0000, The Natural Philosopher
wrote:

I would not bother to remove the old pipes.

Just trace em and re-route alongside.

Or re plumb the entire house.

The hot and cold water pipes between the kitchen and bathroom are the
only bits of original plumbing left from when we moved in (or rather,
they will be after I've finished re-plumbing the kitchen). So this would
basically complete the job of re-plumbing the entire house. I will
probably just take plastic through to the threshold of the bathroom and
connect them up to the 3/4" for the time being. The bathroom will have
to wait.

Its been note that houses get a makeover every 15 years or so, a major
refit every thirty, and a gut and replace every sixty...

However7 0's built houses seem to need the gut and replace after 30 years...

Well, mine's a mid-1880's victorian house, but it seems to have had a
big re-fit in the late 60's or early 70's (I'm guessing this would have
been when the outside lav was removed and the downstairs bathroom
extension added). The standard of workmanship has proven to be fairly
low throughout, even by early 70's standards - clearly not DIY-ed, or if
it was, then it was done by someone who just wanted to do the minimum
required to sell the house at a profit.
--
Chris Cowley

On Wed, 15 Feb 2006 13:12:21 -0000, "Christian McArdle"
wrote:

The 3/4" copper pipes between my kitchen and downstairs bathroom would
have been laid some time in the 1970's I reckon.

The worst thing is that due to the 1970s copper shortage, your copper tube
might be half the British Standard thickness.

Woohoo! It just gets better and better, doesn't it?

As a matter of interest - when did 22mm pipe start to be commonly used
rather than 3/4" as that may help me date the existing plumbing work.
--
Chris Cowley

Chris Bacon wrote:

It'll either corrode, or wear through due to movement caused
by thermal expansion of an unprotected pipe. The bitumen
under the parquet floor is adhesive.

The co-efficient of expansion for iron and concrete is about the same
othewse they couldn't use iron to reinforce concrete. I doubt there wll
be much mechanical stress. But even water will wear through pipes as
the local councils and waterboards have found to their cost since they
started replacing 1/2" salt glazed pipes with thin plastic accidents
waiting for the day.

"Matthew" wrote

We moved into a 70's house last year......SNIP

We have suffered the same fate in a new-to-us 70s house 3 years ago.
But this was a hot water feed to kitchen sink in extension.
The failure was a crack inside a 15mm 90deg elbow which had obviously been
leaking a fair while.
Many downstairs skirting boards were rotten as a result.
Our ground floor was covered with plasic(?) floor tiles stuck down with
black gunk, so all these were scraped up to allow concrete to dry out.

The elbow was replaced with a knee bend to reduce stress levels at the
intersection.

Where the original pipes are run in concrete, they have been wrapped in a
hession-like matting and bedded in sand then concreted over. So there is
some allowance for movement. As noted in another post though, there is no
clearance where rad pipes come up through screed.

Phil

Christian McArdle wrote:

The 3/4" copper pipes between my kitchen and downstairs bathroom would
have been laid some time in the 1970's I reckon.


The worst thing is that due to the 1970s copper shortage, your copper tube
might be half the British Standard thickness.


The biggest problem of that era, was not the pipe thickness, but
pinholing caused by extruding pipe through contaminated dies, leading to
inclusions in the wall of the pipe, which subsequently washed out. A lot
of the pipes were sourced in eastern europe AIUI, so the quality
standards were a bit iffy. Leaks in new houses with unstressed pipework
were very common at the time (and since).

Regards
Capitol

On Wed, 15 Feb 2006 03:41:59 -0800, Matthew wrote:

Is it comon for copper to be corroded by concrete?

As just about everyone has said, this will happen.

Er ... where's your gas pipework? I'd check that out PDQ.

Thanks for all the info.
I reassuring to think that Im not alone and the house isnt a ringer!
I had assumed that leakage would only occur at the copper joints
however it sounds like the pipe itself may also have small holes. I
will dig the rest of the flooring up this weekend
and take a look. I think for the short term I will replace the pipe
and infill with dry sand. Long term I will probably take drops from the
ceiling but its a major job and our house has a lot of downstairs rads
so the number of drops involved would be high!
I dont know how long the pipework in that area had been leaking for but
it could be
months and consequently the concrete is saturated. Hopefully it will
dry itself out in a few days.

Matthew wrote:
Thanks for all the info.
I reassuring to think that Im not alone and the house isnt a ringer!
I had assumed that leakage would only occur at the copper joints
however it sounds like the pipe itself may also have small holes. I
will dig the rest of the flooring up this weekend
and take a look. I think for the short term I will replace the pipe
and infill with dry sand. Long term I will probably take drops from the
ceiling but its a major job and our house has a lot of downstairs rads
so the number of drops involved would be high!
I dont know how long the pipework in that area had been leaking for but
it could be
months and consequently the concrete is saturated. Hopefully it will
dry itself out in a few days.

I replaced some buried pipes and ran the new pipes behind my skirting
boards.

Matthew wrote:
Thanks for all the info.
I reassuring to think that Im not alone and the house isnt a ringer!
I had assumed that leakage would only occur at the copper joints
however it sounds like the pipe itself may also have small holes. I
will dig the rest of the flooring up this weekend
and take a look. I think for the short term I will replace the pipe
and infill with dry sand. Long term I will probably take drops from the
ceiling but its a major job and our house has a lot of downstairs rads
so the number of drops involved would be high!
I dont know how long the pipework in that area had been leaking for but
it could be
months and consequently the concrete is saturated. Hopefully it will
dry itself out in a few days.

I replaced some buried pipes and ran the new pipes behind my skirting
boards.

The message
from Chris Cowley contains these words:

As a matter of interest - when did 22mm pipe start to be commonly used
rather than 3/4" as that may help me date the existing plumbing work.

Don't know for sure but my late parents new bungalow built in 1968 has
some imperial pipework so circa 1970 at a guess.

--
Roger Chapman

Just a thought, rather the dig up the old pipes it MAY be possible to use
then as "conduit" for a microbore system.

Anyone any views on the idea.

Brian