Could you please inform me what the code of practise is regarding installation of rangehoods. I’ve been told by a plumber that a stainless steel flue needs to be installed through the ceiling with an external outlet whereas the builder says its ok for it to go into the ceiling or cavity above the kitchen cupboards. Would appreaciate info. to prove what the correct method is please as soon as possible.
Since you may be discharging grease fumes, you do not want them building up in the attic where they could create odors or fires. But a stainless steel duct is overkill. An ordinary galvanized flue pipe will work and is the normal method of venting it.