Thimble Help

[casey1brockman]

Long time lurker, first time poster. There are quite a few threads already around this topic, but I've not seen one specifically for my scenario and since I'm a bit paranoid I figured I would ask a question specifically to my scenario.

I'm about to install a pellet stove in my basement (within the next year most likely) and I'm going to run the venting up my finished wall (about 6-7 feet) and out poured concrete side wall and do a clean out T on the exterior of my home, run it up a few feet and then put an end cap on the pipe (unless one of you wise folks tells me otherwise ).

My concern is around the thimble (I want to over engineer this since... you know... fire) I'm going to be passing through .5 inch drywall, 3.5 inches of 2x4, 2 inches of foam insulation, and then 8 inches of concrete. If my math is correct that is 14 inches of horizontal venting. Do I need to be paranoid about attaching the inside and outside thimble pieces? Or as long as i get the thimble through the combustibles on the inside of the home and into the concrete will i be safe? Do they make 14 inch long thimble sleeves?

Thank you in advance for any advice.

 

[bogieb]

The thimble is to keep the heat away from combustibles,

But, at the same time, your code enforcement officer may have other ideas.

 

[Mt Bob]

It is not uncommon to make an inner thimble extension by using a wrap of thin sheet metal,and meets code in almost all places.