copper pipes in concrete

I read on old messages in this group that concrete attacks copper
pipe. What happens to it? Does the pipe corrode and form pin hole
leaks? I'm a bit concerned because we've moved into a house where the
ground floor is concrete and the pipes are buried in it. The house is
thirty-something years old. How long does it take to corrode? Thirty
years? If so, what will happen: will the floor get damp? Presumably
I'll notice because as the water leaks out the radiators will fill
with air?
I had to shorten a pipe once, when we changed radiators and I put sand
around the pipe. Would this protect it? I suppose I should have used
plastic channeling to cover it?
I would like to add a radiator under the stairs but although the pipes
are visible, they are rigid because they are encased in concrete at
either end. I could cut the pipe but I would not have the flexibility
of movement to let me insert a fitting. Someone suggested a slip
coupling. Where can I find one of these? Does it require a trip to a
plumbers merchant? Is there a better way to make the join?
Reply to
"Does the pipe corrode and form pin hole leaks"
Yes, if the pipe and any joints are not protected by some sort of sleeving they will corrode.
"How long does it take to corrode"
I've seen the results of corroded copper pipes after less than ten years (pinholed) and the signs are obviously a damp damp floor.
"I'll notice because as the water leaks out the radiators will fill with air?"
You'll be more likely to spot it when walking over a damp carpet in bare feet.
" I put sand around the pipe. Would this protect it?"
Not necessarily.
Brian G
Reply to
Brian G
There's some debate about this. I've certainly seen it happen but it may not alawys occur. For further information see
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Reply to
John Stumbles
In article , "Brian G" writes:
It needs moisture to corrode too. A cold water pipe in concrete will attract condensation and corrode relatively quickly, verses a hot water or gas pipe would take much longer, if the concrete is dry. Some concretes are much worse than others.
Failure of mineral insulated cables in contact with concrete was an issue too (again, heavily depended on the concrete composition), but there isn't much still in use nowadays.
Reply to
Andrew Gabriel
I have some experience of this having bought a 1970s place 5 years ago. When we moved in I discovered that the damp patch near a patio door was not a leaking door, but leaking pipe work. Worry not - this was down to a fractured elbow rather than concrete attacking the copper. The pipe in my place appears to be in a sort of hession wrap laid in sand with a concrete capping over the channel. When doing repairs, I have wrapped the pipes in dpm and bedded them in sand. To get access to pipes for jointing it was necessary to open the channel a fair distance from the proposed joint location. This provides sufficient unrestrained pipe to spring them up for cleaning etc.
On the subject of concrete/mortar attacking the copper then it may well do IMHO, if the wet concrete contacts the pipe while setting. A neighbour of mine came round to complain of a hissing noise from the corner of his kitchen. Turned out to be the main water feed which had some original mortar stuck to the face of the 22mm copper that had eaten through the pipe wall in about 35 years.
Reply to
My mates 1971 house in about 1996 has damp patches in the carpet downstairs due to pin hole leaks in central heating pipes. My house built at same time and same method, nothing obvious.
Cut out with angle grider (messy messy messy) replaced with 15mm copper in plastic pipe (Hep20 push fit pipe).
Once done cemented back, carpet relaid, carpet cleaned the damp patch/stain disappeared and didn't come back.
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