ventilation to a flat roof

Hi all, i am currently building a single story extension to the rear of my property, i have installed a cold roof on this and have had the building inspector out to check it he passed the roof but wants an abutment vent fitted to the rear wall of the property to enable the roof to breath, i have a contineus vent in the new soffitt, but i dont have the room from roof to window ceil to but the abutment vent in can anyone please advise of anouther way this can done is there such a thing like a flat roof vent that can be posistioned on the roof, what would i have to do to the joists to enable them to allow air flow through them, many thanks any advise would be a great help.

Regards Rich.

Mushroom vents

If you can access the underside of the deck, then pack insulation fully between the joists and tight up to the deck, ensuring no air voids, and then you don't have to ventilate

AFAIK, there are no vents available for placing in flat roofs - and practically speaking, you don't want any penetration of a flat roof covering in any case

As Nige has said, mush' vents are used to vent flat roofs.

The last time i used them was about 14 years ago in London.

If you do as Woody has said, use rigid foam insulation to pack the void and not fibreglass as this fills with air.

Rytons make them and you can buy direct from them

Would a vent like this help?