I have had a new single story extension built to first fixtures; this includes a new kitchen area. Building Control (UK), will not sign off the extension until an extractor hood is fitted with external ventilation.
To give an overview of the issue, the location of the Cooker hood is to be located on an external load-bearing wall, which is supporting a steel RSJ beam, because of this I am unable to place the ducting straight out of the wall, or out through the ceiling above. Therefore, I plan to use rectangular flat ducting to hide behind the cornice and come out at a different location along the wall.
My main concern is the height of the cabinet means the ducting will come out approximately 20cm (2 bricks), lower from under the eaves and directly centre between the joists.
I would ideally like to have the vent come out higher up the wall so the cabinets can sit higher, it will then mean that it will only be 10cm from the eaves.
I have considered boxing in the ducting so it protrudes further out than the guttering but this will be unsightly.
In the UK, is there a minimum distance the vent can be to the eaves/guttering and joists?
Any guidance or other suggestions would be a great help.