Partial chimney breast removal and vents

[xyz123]

Hi, as part of loft conversion we will be removing the chimney breasts in the loft area. Chimney stack abkve roof line will Remain as is and supported by a steel beam. Chimney breast in ground floor and first floor will also remain as is. There is no gas or wood fire.

Do I need to worry about any ventilation in the remaining section of chimney breast on ground and 1st floor and if so what to do?

Thanks

[JoshSm]

Don't see why it'd need much in the way of ventilation as it shouldn't be getting much in the way of moisture in it once the top is gone, not like the situation with a full stack + blocked fireplaces.

Should just be enough to leave the top of the remaining stack open into the floor void which I assume was the plan anyway?

Question is what do you do with the upper stub if there's a loft conversion? I'd have thought that *would* need a base slab/vent/trickle drain to deal with any water ingress as I guess it'll be directly above a ceiling?