Copper or Barrier Pipe - Lime Wall

[Rawler]

Getting conflicting advice from plumbers and internet regarding whether it's better to use copper pipe or barrier pipe in a lime plaster chase. Anyone have any experience or recommendations? Many thanks

 

[paulc]

I'd favour sleeved copper pipe. 15mm copper is a nice sliding fit in 20mm plastic conduit. Just don't use fittings buried in the wall, make sure you clean off & neutralise flux. Also worth using a 25/35mm single back box where the pipe comes out of the wall - Gives you easy access to solder the final fitting on, and a blanking plate will finish it off neatly.

 

[a twig]

Most plumbers I talk to nowadays refuse to chase in pipes - citing expansion and contraction causing cracking in the plaster.

Although I suspect the reality for most of them is in fact driven by a desire for an easy life of surface mounted / boxed in pipework

 

[Rawler]

I'd favour sleeved copper pipe. 15mm copper is a nice sliding fit in 20mm plastic conduit. Just don't use fittings buried in the wall, make sure you clean off & neutralise flux. Also worth using a 25/35mm single back box where the pipe comes out of the wall - Gives you easy access to solder the final fitting on, and a blanking plate will finish it off neatly.

Thanks Paulc. Sorry, are you suggesting surface mounted, or chased but with allowance for 20mm plastic conduit?

 

[Rawler]

Most plumbers I talk to nowadays refuse to chase in pipes - citing expansion and contraction causing cracking in the plaster.

Although I suspect the reality for most of them is in fact driven by a desire for an easy life of surface mounted / boxed in pipework

Thank you. My plumber was suggesting that the expansion is along the length of the pipe (so floor to ceiling in the case of a vertical run pipe down the walls), but I'm a little concerned that they will get chased in and plastered over only for them to crack the lime in time. They are also suggesting barrier pipe in the walls...

 

[paulc]

Thanks Paulc. Sorry, are you suggesting surface mounted, or chased but with allowance for 20mm plastic conduit?

Chased in deep enough for 20mm conduit. Before plastering begins, put the plumbing in place, making sure no buried joints. Fill the chases with a coarse plaster/mortar, then plaster as normal. Some scrim tape over the chases will reduce the risk of cracks forming. Allow the new plaster to dry out thoroughly before running hot water through the pipes.
I have a pair of 15mm pipes feeding a radiator that have been chased in to a wall (sleeved in 20mm conduit). No sign of the plaster cracking, but most of the wall is papered apart from the top foot.

 

[Rawler]

Chased in deep enough for 20mm conduit. Before plastering begins, put the plumbing in place, making sure no buried joints. Fill the chases with a coarse plaster/mortar, then plaster as normal. Some scrim tape over the chases will reduce the risk of cracks forming. Allow the new plaster to dry out thoroughly before running hot water through the pipes.
I have a pair of 15mm pipes feeding a radiator that have been chased in to a wall (sleeved in 20mm conduit). No sign of the plaster cracking, but most of the wall is papered apart from the top foot.

Thanks Paul