Cutting into a chimney breast

[angliojoe]

Hello,
I have a chimney breast on the ground floor of my home. The breast and stack has been removed from the first floor upwards so this is the only piece remaining.
I want to angle grind a rectangle out of the breast at waist height and then put in a plywood box to create some sunken shelves. I’ll put in a lintel to handle the brickwork above the hole but wanted to check, is there anything else I need to consider in regards to damp or pollutants from inside the chimney or anything else?
Many thanks,
Joe.

 

[tell80]

What you propose is fine.
Minor problems might be soot in the old flue but you could have that bit of flue swept.
The box opening could be blinded with backer board before fixing any finished Ply/melamine?
Is the outside of the back wall pointed brickwork or is it rendered?

 

[angliojoe]

@tell80 thanks for the reply. The back wall is rendered and in good standing but will check for damp etc. What’s the need for backer board? Is that to avoid damp?

 

[tell80]

To avoid any contamination coming thro onto the finished board surface.