Cold bridge between aluminium frame and steel beam?

[thefoxesmaltings]

We have a structural steel beam which sits in-between a aluminium ground floor screen and a aluminium first floor screen. From the exterior we are aiming to clad this steel beam with a aluminium flashing to create a seamless 'frame' in-between the ground floor and first floor screens. Otherwise we'd see a exposed steel beam there.

 

Glazing company has stated:

We would normally ask/recommend that any steel is first clad with a minimum 15mm marine plywood, prior to the flashing. This helps prevent a cold bridge and provides a good foundation to fix and bond to. We can clad this junction as it is but wanted to ask for input.   

 

My concern is, that by cladding this steel beam with ply, they are then stating that a ‘potential trim’ is needed inside, as the frame finish could be lower than where the plasterboard will meet at the ceiling. I’d rather the glazed frame be sitting flush, or completely within tolerance so that any plasterboard or floor covering can come up to it and achieve a nice detail.

 

Are there any issues not cladding the steel beam with marine ply?

 

Sectional detail produced by Glazing company below.

 

[ETC]

Why don’t you just install the ceiling once the glazing panel is in?
 

Alternatively either drop or raise a section of the ceiling to the edge of the glazing panel.