Recess shelf in cavity wall

[aaron1987]

I am doing the bathroom and have thought about putting a recessed shelf in one of the walls. Like the kind you get in showers to put bits on.
The wall I'm wanting to do this in us the external house wall. It's a cavity wall, breeze, cavity then brick.
I am wondering of best way to do this?
Whether to knock a full breeze out and then try and mount a back board.
Or to chip away at breeze to leave a bit of breeze in?
Wondering what people's views are? Also people views with regards to structural integrity and insulation?

 

[tony1851]

To have a worthwhile depth of shelves, you would need to take out the full depth of the block; the block won't be up to cutting part-way through.
Assuming the unit is not too wide, there won't be a structural issue.
Make up the box out of mdf and secure it with fill-and-fix foam

 

[jay679]

I did this in a kitchen refit and it looked great. If in a bathroom either over the bath or shower area, I would build the box in some sort of aquapanel, seal it well and tile it.

Jay