Wall thimble through raised metal panel

[atvkid4eva]

I am installing the vent pipe for my Reverberay Tube Heater. My shop has metal wall liner installed on the interior with the raised rib sections running vertically. The outer square surface of the thimble looks like it it going to rest on the ribs of the panel. Any suggestions on how to get it to sit flat? Any pics of similar installs would help greatly. Thanks!

 

[Walkers]

Cut the hole first, then cut a couple of half blocks 1/2 the size of the square portion and sandwich the liner with them and clamp them together. It will flatten the area out, then move the half blocks to the other side and repeat.

 

[finn]

That’s why the thimble is built with a sliding collar. It should be deep enough to accommodate the ribs, and you’re never going to see that it’s not flat against the siding once it’s installed unless you put your cheek against the wall.

The other option is to build a box structure that raises the exit point to the height of the ribs, but you’re not fooling anyone.