Shower Mixer Installation With Limited Space Behind Wall

[triz]

As part of my first bathroom renovation, I am planning to install a new shower with a bar mixer above the bath, with pipes going up from under the bath behind the wall to the mixer. Here's what the pipework to the current bath tap looks like:

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For both the hot and cold pipes, I think I'll need to cut off the old pipework just above the floor, put in a combined check/isolation-valve, and then a T-joint to which I can then re-connect the tap, and have a pipe going up the wall to the new mixer.

To get the pipes for the mixer behind the wall, I'm planning to remove the dot-n-dab plasterboard behind the bath, batten out the wall by 2-3cm, and replace with cementboard, giving just enough room for the 15mm pipe and clips.

Does this sound like a reasonable plan? I am still quite new to DIY, and this will be my first plumbing project, so any help would be greatly appreciated!

Cheers

 

[terryplumb]

Sounds like a workable plan. Bear in mind ,shower mixers need the hot and cold in specific orientations and distances apart. Typically ,but not always , hot on the left and 150 mm centres. What supplies the hot water ?
Combi boiler ,gravity fed hot water cylinder etc ?

 

[triz]

Sounds like a workable plan. Bear in mind ,shower mixers need the hot and cold in specific orientations and distances apart. Typically ,but not always , hot on the left and 150 mm centres. What supplies the hot water ?
Combi boiler ,gravity fed hot water cylinder etc ?

Thanks for the advice. The hot water is supplied by a combi-boiler. Would it be worth getting pipe benders to achieve the correct distance between the pipes?

 

[terryplumb]

Pipe benders to achieve distances ??
Don't get where you are coming from ?
Most horizontal bar mixer valves require 15 mm pipes to come out the wall 150 mm apart and horizontal.
Can't tell from your pic ,but those pipes look more like 22mm ,or if old ,3/4 inch.

 

[triz]

Pipe benders to achieve distances ??
Don't get where you are coming from ?
Most horizontal bar mixer valves require 15 mm pipes to come out the wall 150 mm apart and horizontal.
Can't tell from your pic ,but those pipes look more like 22mm ,or if old ,3/4 inch.

Sorry wasn't very clear in my last post. To get the pipes to come out the wall 150mm apart, I'm assuming I'll need to bend them as they go up the wall so that the centers are spaced 150mm apart at the top where they will then come out horizontally with an elbow joint. I think you're right about them being 22mm, I guess I'll also need to put reducers in at the bottom of the pipework then, to bring them down to 15mm.

 

[terryplumb]

You can arrange the vertical sections of pipe as you wish ,by bending or using elbows, as they will not be visible. As long as they come out the wall in the positions you need to connect to the valve. Be aware that lots of horizontal bar mixers come with fittings that are threaded and " dog leg" shaped. Take my advice and don't use them ,but purchase a bar mixer fixing kit. It will make it easier for you.

 

[flameport]

To get the pipes to come out the wall 150mm apart,

https://www.screwfix.com/p/h-c-contemporary-bar-valve-fixing-kit-chrome-effect/76919

 

[triz]

Thanks for the tips. Those fixing kits look very handy, will definitely make my life easier!