Choice is go up to roof 5 6 feet or out the present vent 15 18 feet with insulated pipe or shorten the line by going straight to side of home but this requires going up high with latter to drill a new vent hole as tight quarters in attic prevent drilling from attic.
Venting kitchen extractor fan through roof.
Ventilation codes are regulations with the force of law.
Screw the ductwork together.
Start in the attic and drill a hole through the roof in the desired vent location.
You can buy the proper flashing to install it on a flat roof and a roof cap that has screen around it to prevent insects from entering.
Try to keep it close to the fan location.
Connect the ductwork with sheet metal screws wrap the connections with aluminum faced duct tape then wrap the attic part of the duct work with an insulated sleeve.
Vent through the roof.
Authority for regulating ventilation in buildings is left up to each state and usually that authority is delegated to local jurisdictions counties and cities.
In the u s no national ventilation code exists.
With the vent hood hooked up turn it on and make sure the lights and fan work.
Going to the soffet is 12 feet.
Leave the drill bit sticking through the roof so you can find the hole.
Run duct work through the attic then attach the stove vent to a roof cap.
From up on the roof use a jigsaw or reciprocating saw to cut a 4 in.
In the u s no national ventilation code exists.