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[Sir Tigger KC]

I had a leak in a buried pipe where it goes under the kitchen floor to the bathroom which I've dug out and fixed the leak. 

This morning I wrapped the pipes in Denso tape before cementing over, but after wrapping the pipes, I washed my hands in the bathroom and when I went back to the kitchen I found that the tape on the hot pipe had turned to mush! 

This dosn't seem normal to me, so I thought I'd better get professional advice from the OOFeratti before I bury the pipes in cement. 

[dave the builder]

Don't bury copper pipe in cement/concrete 

copper pipe will corrode, you will get massive heat sink into the concrete (underfloor heating )

obviously you will ignore that advice 

 so.......

 put closed cell insulation lagging on clicky wrapped with waterproof tape 

[Sir Tigger KC]

Don't bury copper pipe in cement/concrete 

copper pipe will corrode, you will get massive heat sink into the concrete (underfloor heating )

Whoever laid the pipes there in the first place wrapped the pipes with duct tape, which obviously wasn't up to the job of protecting the pipes from the corrosive alkaloids in the cement.  I thought that Denso tape was the proper stuff to use?   

The 'trench' isn't deep enough for the foam insulation stuff you linked to, so that's no good. 

If I hadn't washed my hands, it would all be nicely encased in cement now and odds on I wouldn't have been any the wiser...   

[STEMO]

Denso tape is for a temporary repair on cold water systems where there is no pressure, i.e. rainwater pipes, gutters, etc. It's basically no more than grease held together with fabric.

[dave the builder]

Don't bury copper pipe in cement/concrete 

copper pipe will corrode, you will get massive heat sink into the concrete (underfloor heating )

Whoever laid the pipes there in the first place wrapped the pipes with duct tape, which obviously wasn't up to the job of protecting the pipes from the corrosive alkaloids in the cement.  I thought that Denso tape was the proper stuff to use?   

The 'trench' isn't deep enough for the foam insulation stuff you linked to, so that's no good. 

If I hadn't washed my hands, it would all be nicely encased in cement now and odds on I wouldn't have been any the wiser...   

ask the OOF mod team to delete this thread, cover pipes up, take a blue memory loss pill, job jobbed 

[STEMO]

Piccy please.

[Andy H]

Wrapping pipe in Denso tape is an age old attempt to prevent the cement burning through the copper but as you have rediscovered Denso is not heat resistant (I think it is fabric impregnated with wax or grease )

Running pipes in the screed pretty much guarantees that screed will crack along the line of the pipe - (this might not matter to you depending on what your final floor covering is)

Insulating the pipes is probably not an option as the overall diameter of the insulated pipes will be close to the depth of the screed.

When I pulled up the floor screed of the downstairs bathroom in my house the copper pipes had a factory PVC sleeve which seems to have prevented corrosion and coped with heat. When I re-piped it I clipped the pipes to the wall....

[STEMO]

Wrapping pipe in Denso tape is an age old attempt to prevent the cement burning through the copper but as you have rediscovered Denso is not heat resistant (I think it is fabric impregnated with wax or grease )

Running pipes in the screed pretty much guarantees that screed will crack along the line of the pipe - (this might not matter to you depending on what your final floor covering is)

Insulating the pipes is probably not an option as the overall diameter of the insulated pipes will be close to the depth of the screed.

When I pulled up the floor screed of the downstairs bathroom in my house the copper pipes had a factory PVC sleeve which seems to have prevented corrosion and coped with heat. When I re-piped it I clipped the pipes to the wall....

There's an echo in here.

[dave the builder]

what floor covering is going down on top ?
if laminate planks, you could use expanding foam rather than concrete
(giving the pipe insulation )

or re-route the pipe ,as Andy says

or swap for b-pex pipe if you want the underfloor heating aspect 

[Sir Tigger KC]

Piccy please.

Sorry no piccys available till Tuesday as I'm not back  there until then, which is why I wanted to cement it over today so it could dry out undisturbed for a few days. 

what floor covering is going down on top ?

Ceramic tiles, so it'll need a solid base to stop the tiles from cracking. 

Re-routing the pipes isn't an option, as that would be a massive job pulling the kitchen units out and they'll get wrapped in duct tape again before that happens!   

Nothing is ever ficking straight forward is it?   

[dave the builder]

this is why,when designing a kitchen etc, you need to plan ,starting with the services .
don't clicky  

[Doctor Gollum]

Fill the 'trench' with sand and lay the tile over it

[Lizzie Zoom]

How about using gaffer tape?

[biggriffin]

Another wurzel bodge up, have you been on ch5 yet dodgey old landlords.

[Bigron]

Bitumen roofing sealant?

Ron.