Wall thimble - sealant necessary?

[Alexander L]

Hi all! Started my install and got the wall thimble in place.
Had some questions about using sealants at certain areas of the thimble.

First - the spot where the thimble passes through the exterior siding/sheathing. Looks like I can seal gap between sheathing and metal thimble from the inside. Is this necessary? It is not called for in instructions... but seems like a good way to keep out weather - moisture - creepy crawlers - yeti, etc.

Second, where the class A pipe passes into the thimble flashing on the exterior of the house. This is not a very large gap... just wondering if it is standard practice to use sealant here to keep any water, etc. out of the thimble/wall assembly. I have a few tubes of RTV if needed.

I am not sure if the pass thru gap in the tee is supposed to stay unsealed for venting?

Last, I imagine it is perfectly safe to stuff some roxul mineral wool insulation into the frame for the thimble? If the outer thimble can contact wood shims to secure, makes sense that insulation is good, right?

Thank you!

Pics with red arrows to illustrate:

 

[kennyp2339]

Any regular silicon caulk will work, but for added measure the high temp will do the same job, don't forget to move that little wedge from under the horizontal class a pipe

 

[edyit]

that's not class A, that's the wall pass through, that's what gives you the clearance to combustibles. The Class A slides through the hole he has taped off.

 

[kennyp2339]

that's not class A, that's the wall pass through, that's what gives you the clearance to combustibles. The Class A slides through the hole he has taped off.

You are absolutely correct, my bad.

 

[Alexander L]

So, these gaps in the thimble can be sealed, and are not necessary for any venting of the thimble/through wall assembly?
The instructions only call for sealing at the edges of the square exterior flashing (where it meets the exterior wall/siding.
Appreciate your time and info!

 

[begreen]

Seal the edges of exterior flashing. I also run a bead around the pipe where it enters.

Note that silicone sealant will not keep out a yeti. Have camera ready for its entrance and some cookies. Yetis love oatmeal raisin cookies.

 

[Alexander L]

Ha! Excellent! Will seal at those spots. Thank you.
Roxul mineral wool insulation is fine in contact with the metal thimble? Makes sense that it would be. Plan to stuff it in the framing.