I'm in the process of renovating a bathroom and noticed when removing the old fan that the exhaust duct ran vertically into the roof cap but wasn't connected to it in any way, rather it was just sitting up in there, being held up by its connection to the fan. Is this a typical installation that I can repeat with the new ducting or does it need to be secured and sealed within the roof cap? I'm concerned about moist air dumping into the attic space rather than completely out the roof cap. Hopefully this pic illustrates the question, you can see all the space around the duct where it pokes up into the cap. Thanks!