Posted this on the Screwfix forum earlier today but a bit quiet over there and not much feedback, so thought I would see if its any livelier over here ?!!!

I have a Crosswater recessed two outlet shower valve to fit when I refurb our home bathroom.

It's going to be fitted in an external wall (brick/cavity/block) which I have to chase out, but I am not entirely sure how to secure the valve in place once the recess is made.

The instructions are a bit lacking and because I'm not a pro and haven't fitted one before (although done a lot of other plumbing over the years) I didn't want to learn the hard way and screw it up !

The depth of mounting in the recess appears to be pretty critical so that the flush mounting surface plate and controls fit over the tiling afterwards.

Not sure whether to line some of the sides of the recess, or the inside face of the external brick skin, with timber and fasten to this (damp bridging problem possibly if fastened to external brick skin?), or whether just to rest the weight of the valve on the bottom of the recess ?

Also haven't thought yet how to fill/cover the pipe chases prior to tiling so any guidance on that would be appreciated also.

Many thanks,

I generally supply and fit Aqualisa showers and fitting them into a cavity wall can be a problem as, by the time you've chopped out a big enough recess for the valve, you're right through the blockwork.

What I do if I can, is reverse fix a panel of 18mm wbp ply to the back of the block, through the opening I have chopped out.  This ply is fixed to the block using 120mm or 150mm rustproof screws.

The screws need to be this long to go through the block 100mm and to grab the ply and pull it tight to the back of the opening.

To fit the ply is a bit of a balancing act.  I screw in a long screw into the middle of the ply to act as a temporary handle, poke the ply through the block and thread it into the cavity, then pull it back against the blocks using the screw handle.

You can then fix it properly with a long screw in each corner and then remove the 'handle'.

This ply can then form the backboard for your valve installation.  Often you have to pack out against this ply as it may be too deep for your particular valve.

Hope this helps.

btw, the ply (being wbp) will be fine in the cavity as long as there is insulation between it and the outer brickwork.

Yes I have fitted the Quartz! (that's the one with the separate controller with Cat5 cables?)

These are much easier to install I agree, just a 15mm supply to the handset outlet and a plug in control switch.  I like the flashing light indicator too.

Perhaps I should push these more..........  

Can these Quartz take a Stuart Turner 3 bar pump?  ???

I know there is a 'built in pump' Quartz but these go nowhere near 3 bar.  I was considering pumping the 'standard' Quartz (but to 3 bar)

It seems most people I install for all want minimum 3 bar shower pressure nowadays

Many thanks.