There are many questions on here about installing duct work for bathroom fans, but I have a more specific question. I am planning to use rigid duct for a new bathroom fan where there was none previously. The fan is installed under the attic floor, which is currently removed for other work. After the floor is re-installed and the attic room re-finished, I would like to be able to replace the bathroom fan (as I will probably have to some day) without having to cut additional holes in the bathroom ceiling (lathe and plaster) or attic floor.
How do I remove the bathroom fan from the ceiling if it is rigidly connected to the rigid duct? Most online videos show flex duct, and you can simply pull the sidewall part of the fan assembly down from the ceiling enough to disconnect the clamp. With rigid duct, this is obviously not possible.
My original plan was to connect the rigid duct to the fan with screws and mastic. Could there be some other method, like a clamp with rubber insert on the ID to hold a strong connection and provide an air seal, that could potentially be removable? I could imaging either wiggling the sidewall back and forth to pull it loose from such a clamp, or maybe reaching over the fan sidewall to loosen a securing nut (joist bays are only 2x6). Any suggestions are appreciated.