Hello all,
I am a new member here.
I am in the process of overhauling my dryer venting. I have a 2x4 wall behind my dryer. I am thinking of using one of the dryer boxes for 2x4 walls but I am concerned about compressing the 4 inch duct inbetween the drywall to form a slight oval and the heat it will see since it will be in contact. Is this a firehazard? Do I need to use a special drywall?

Background: The current duct in the wall is 3x4 rectangle and has not been in use. The dryer was vented into the garage instead by the previous owner. It appears to be custom made and fits nicely in the wall (1963 home). I don't know how to connect to it with out it looking cheesey, hence switching to the 4 inch round. At the top of it, it appears the builders used a 5 inch to 4 inch reducer to adapt from the rectangular duct to the 4 inch round that completes the last few feet before going thru the roof.
Appreciate any help.