Channelling brickwork for hidden pipes

[AdamW]

I wish to channel into my bathroom wall in order to hide pipes for a shower. The wall is an exterior wall. I have taken the tiles off and it appears to be made of grey aerated blocks (breezeblock?) with about an inch of plaster on the inside.

I have bought a "plugging chisel" as I was told this is the best tool to use for channelling. Is this correct? It looks a bit like a butter knife, not sure what angle to hold it at when I whack it!

Do I drill holes at regular intervals first of all and then chisel, or do I JUST chisel? What is the likelihood of putting cracks into the masonry that are going to cause problems?

 

[masona]

I have bought a "plugging chisel" as I was told this is the best tool to use for channelling. Is this correct?

Not really as it for removal of mortar between bricks.

You need wall chaser which can be expensive but screwfix do one cheaper but depending on the depth & width you need.Tools hire shop should be able to help you.See this.

 

[xbond]

Does anyone know what the building regs say about channeling copper pipes into solid walls and concrete floors, how deep they need to be & what is required to protect the pipes from corrosion & expansion?

On the continent I have used grey flexible PVC conduit, but can't seem to find anything similar here, looked at screwfix and others, does anyone know where I could source something similar?