Hope some one has some ideas.. I am using duravent venting to vent a reznor heater.. it will be class 3 stainless steel.. I need to use a wall thimble to go thru the wall I will provide a link to a picture...my problem is mounting the thimble to the outside and the inside both have corigated steel installed.. and due to the ribs of the wall the square part of the thimble will not be flush due to the raised ribs...anyou ideas.... here is a link to the thimble
https://www.plumbersstock.com/durav...MIosWQgdr91gIVyF5-Ch1DcQ2sEAsYASABEgKvBPD_BwE
Thanks Jim
https://www.plumbersstock.com/durav...MIosWQgdr91gIVyF5-Ch1DcQ2sEAsYASABEgKvBPD_BwE
Thanks Jim