concealed pipes to a shower

[Dave]

I need to run concealed pipes from beneath the floor to wall-bracket compression elbows for a wall mounted shower mixer, but can't decide the best way to do it. I'll need to cut a duct in the blockwork, is it best to mortar-in the pipes or to use exterior ply over the duct (there'll be tiles over the top)? Is it best to use copper or barrier pipe? I'd be worried about the mortar attacking the copper but presumably the plastic barrier pipe doesn't need protecting(?) Are there any problems using regular compression fittings on barrier pipe?

[Ian Stirling]

Me, I'd be tempted to go with the exterior ply option. (I'd also keep aside the requisite number of tiles to replace ones if access is needed to the pipe)

Mortar will attack the copper - sooner or later.

I'm pretty sure you need special fittings.

And a sharp hacksaw, or a dull axe to cut it with. (use a proper cutter, or ensure that the edges are precisely square and burr-free.)

[Dave Jones]

Either option ok

Again both ok

Provided that you use pipe inserts no problem

[mrcheerful]

I would not use compression fittings as you won't be able to inspect and retighten if necessary.

I would fix them using pipe clips in the base of a cut out in the brickwork and cover with ply preferably, but I have had no trouble with ones that have been plastered in, mortar might be different though.

mrcheerful