Venting pellet flue through concrete/stucco

[Slyther]

I am venting a pellet stove to the outside wall from my finished basement (2 foot above gradient). After the inside wall thimble, beyond the studs I am at concrete block with a stucco exterior.

My question is, do I need to use the thimble on the outside or can I just run a 3.5" hole through the concrete block and stucco to run the vent pipe directly out and not have to enlarge the hole to fit the thimble (I will be adding a 90 degree bend to cap off the pipe at 3-4 feet above ground level)? If so, can I use concrete patch inside and around the vent pipe in the concrete and stucco around it after I put it in (to seal it in place, similarly to a dryer vent)?

Thanks in advance.

 

[zrock]

Under your stucco is usually a rigid Styrofoam that is pretty flammable... best to call and ask your local wett inspector

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[MtDew]

You have a very similar setup to mine. I did just what you are asking about. Interior use the thimble, exterior just a hole slightly larger than the pipe and seal with concrete patch mix.

As long as there is no insulation behind the stucco as zrock mentioned. Mine was just a thin coat of stucco applied directly to the concrete block on the outside.

 

[Slyther]

Thanks a lot guys- no insulation, stucco directly on the concrete. Will go ahead with the concrete patch!