brightspark
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my gas and water pipes been under the screed for 35 years just wrapped with duct tape. no problem
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Rig Pig
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s
That's how I clocked we had an issue, the carpet and underlay did a great job of suppressing the water coming through, so it took to the walls
This was the end result, I took the opportunity to knock out the dining room wall gutted out all the mouldy units and started again.
eLuSiVeMiTe
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I thought I was going mad looking for it. Assume you mean the kitchen cabinet with stuff on top?Is that a lathe in you kitchen @Rig Pig ?
Seadog
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mangocrazy
Italian V-twin nutjob
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I've heard a number of plumbers say that half the problem is with modern copper pipe. Wall thickness is greatly reduced and the quality of copper is not what it was. As a result, modern copper pipe is far more easily attacked by concrete.
WorkshopChris
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The copper is under the screed in our extension(in that brown fluff plastic backed insulation), Dad put it down in the early 80's my job after the screed was set was to pain white lines on the floor following along the runs, to prevent that very thing happening.
Thicker pipe just means it takes longer for the reaction to eat all the way through, it doesn't make it harder for the cement to attack it.
Just had a thought about lime mortar or limecrete and whether that also reacts? Am I right in thinking lime is also a strong alkali?
brightspark
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copper is still a decent thickness . when there was a copper shortage they brought out red stripe tube. it was that thin you couldn't bend it without kinking it . so if it bends ok it isn't that thin 
at the time of shortage they brought out aluminium cable and that's a disaster
when you make the ends off and tighten them up it creeps comes loose then overheats and burns out in a short space of time
at the time of shortage they brought out aluminium cable and that's a disaster when you make the ends off and tighten them up it creeps comes loose then overheats and burns out in a short space of time
mangocrazy
Italian V-twin nutjob
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That also depends on the purity of the copper. Impurities will be more easily attacked.
brightspark
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copper pipe isn't that pure. nowhere near copper cable quality
Wrap the copper in Denso tape. Then line the channel with dpm. Screed over that, but use some cement dye to colour the infill. That way it will be easier to identify the pipe run.
If using 15mm copper, the Denso can be unrolled along the pipe length and moulded around the pipe. Definitely wear gloves!
If using 15mm copper, the Denso can be unrolled along the pipe length and moulded around the pipe. Definitely wear gloves!
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Why go to all that bother? Denso is horrible. Just use plastic pipe with no hidden joints. Pressure test it before screeding for belt and braces.
Pete.
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From a demolition point of view I've seen copper pipes come out from screed looking like new and I've seen it paper-thin with green/black blotches and I've seen it pock-marked like the face of the moon. Jump in your TARDIS and go forward 20 years, you'll know which way yours is going to go.
Never seen any of the plastic coated stuff go rotten.
Never seen any of the plastic coated stuff go rotten.
julianf
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What's your reluctance to use PEX, as I previously mentioned?
It's what they use in underfloor heating, so is tried and tested in the application.
HughF
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Exactly, just get some 16mm PEX-AL-PEX and throw it in there. Personally I'd plum an entire house in the stuff it is so much nicer to work with compared to regular pex
dobbslc
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No reluctance I just never thought of it!
Pex Al Pex! Now I'm confused! What's the difference between Pex & Pex Al Pex?
