Is it ok to put pipes under concrete
in In my home (includes DIY) MoneySaving
13 replies 85.9K views
Is it OK/normal to put copper central heating pipes under insulation and then concrete screed on top. Does it comply with UK Building regs.
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I just re-piped our central heating system from upstairs to downstairs using drop downs for this very reason.
You get no BS from me & if I think you are wrong I WILL tell you.
After about 10 years the cold water pipe feeding the garden tap, which ran the full length of the long kitchen extension, failed and started to leak.
We didn't notice until water started bubbling up through a join in the vinyl flooring. By that time a large area of concrete was saturated and it took weeks with a noisy dehumidifier and fan to dry out the floor. We had to lift half the vinyl, which thankfully we were able to reuse, and live with the noise and mess for weeks.
I isolated that pipe under the sink and replaced it with a plastic pipe that I ran under the kitchen units.
A few years later another pipe failed and we had the same problem again.
I dug up all three copper pipes and replaced them with plastic pipes run in a plastic flexible conduit.
The pipes had all been properly wrapped in insulation but had still been corroded by acids or alkalis or whatever was in the concrete.
Our insurance covered all the costs on both occasions but I still would not to go through all that again.
My advice is to avoid running copper pipes in concrete if possible.
Can you use plastic pipe in plastic conduit instead? That means you can have one continuous run with no joints and the plastic pipe should last indefinitely. If it ever does need replacing you will probably only have to dig out at either end and feed new pipe into the conduit.
I don't know what the current building regulations require.
Insulation is the wrong material to protect copper pipes in concrete or cement screed. It allows the passage of alkaline moisture to get to the copper. You need a specific waterproof wrapping like Denso tape, vile stuff to work with... If at at possible dont bury pipes, copper or not.http://compare.ebay.co.uk/like/400146706091?var=lv&var=sbar&_lwgsi=y&cbt=y&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=66
Plastic is inert and resistant to the concrete and provides some flexibility to replace the pipework in the future.
I'd agree with not running pipes in concrete but on the other hand, my dad's went in in the mid '70s....flow & return heating plus gas. Gas was plastic covered copper pipe with the joints wrapped in denso tape, heating was just bare copper with the old split insulation. 40 years on he has had no problems. Maybe it's a different concrete mix?
Some people place pipe in pipe, and have junction boxes with removable covers. One person I know raised the floor, creating a false floor above screed, and placed copper pipe below the false floor. It sounds a good idea, but doors will be less than standard height, and cheap doors won't fit as you cannot take much off, so you'll have to have more expensive ones. Protected pipe in screed has the advantage of being cheap, and it seems to work.
Your dad's pipes were protected by plastic. Mine were just wrapped in brown insulation.
I know that now.
I didn't know that in 1993 when we hired the builders. I thought they would know what they were doing.
In the course of our current renovation, we have dug up a multitude of pipes from under the concrete of the floors, ALL of which were leaking, and clearly had been for some considerable amount of time. The damage that this had caused was enormous - you could literally poke your finger through the plaster on the walls in the bathroom, and the place stank to high heaven.
The leaks may just have been due to poor workmanship, as when we dug the sewage pipe up, we found that too was leaking, not due to a failed joint, but because someone had simply propped about half an inch of small pipe into a big old clay pipe at an angle and then just hidden it in concrete. If you flushed the loo and ran to the other side of the room, you could watch the water go past through the gap.
However, we have made sure that when we replumbed the place, all the pipes have been placed so they are either accessible or at least bypassable. The only exception is the sewage, which HAD to go under the floor, but as we did it ourselves, we know it hasn't been bodged up and then hidden under concrete.