# Passing through concrete wall requirements?



## Tmac845 (Feb 24, 2013)

I find myself here again at the fountain of info.  I'm going through a poured-concrete wall with an 8 inch S.S. metalbestos chimney to a insulated tee and I've got a couple of questions.

1:  Do I need a thimble?  There's at least 3 feet in every direction to any combustible.  I'm concerned with "spot cooling" and build-up at the wall.

2:  The Selkirk instructions only show the Tee-support kit going onto a wood-stud wall.  Anyone ever install on concrete?  Should I thru-bolt it, or Hilti some 2x4's on the outside, and lag it as per the instructions?  
Thanks for reading my question.  Thanks.


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## Swedishchef (Feb 25, 2013)

I would install a thimble although i believe e only purpose of a thi,ble is to make sure you have the proper clearances.

For my kit I simply used concrete screws and anchord them to the foundation tomsupport the Tee. Screwed straight into the cement,

Best of luck!

Andrew


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## Tmac845 (Feb 25, 2013)

Swedishchef said:


> I would install a thimble although i believe e only purpose of a thi,ble is to make sure you have the proper clearances.
> 
> For my kit I simply used concrete screws and anchord them to the foundation tomsupport the Tee. Screwed straight into the cement,
> 
> ...


Aren't the clearances required to combustibles?  Concrete is definitely not combustible, so if I pass through with a piece of sure-temp, clearances to combustibles should be no problem.


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## mywaynow (Feb 25, 2013)

I used the wall bracket which was concrete screwed into the foundation.  It needs only to be kept from rotating or walking, since most of the vertical wieght will go to the overall pipe as it is supported by the foundation.  If you are contemplating a thimble vs single wall pipe, the only thing I would say is the thimble will be double wall and provide better resistance to cooling and thus creosote buildup.


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## Slow1 (Feb 25, 2013)

Tmac845 said:


> Aren't the clearances required to combustibles? Concrete is definitely not combustible, so if I pass through with a piece of sure-temp, clearances to combustibles should be no problem.


 
The question I'd be concerned with is how do you plan to finish the inside of that wall?  Leaving it unfinished (and thus uninsulated) would seem to be a rather bad idea.  Most insulation solutions involve some combustibles so putting the thimble may well help keep it safe and provide a good clean solution (visually).


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## Tmac845 (Feb 25, 2013)

It's an unfinished basement (for now...), so it's bare concrete, only exposed on the outside for a short distance, basically enough for a walkout slider and another fifteen feet, then grading changes and foundation is back filled. For now I was gonna go through with a 24" s.s. double wall pipe right to my tee. Mud the pipe in with some mortar mix and call it a day. When I get around to finishing the basement (years away...), ill deal with aesthetics.


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## begreen (Feb 25, 2013)

If the intent will be to insulate and finish this wall in the future, a thimble would be a good idea, but there are workarounds. Regardless, be sure to extend the stub far enough interior to accommodate for the intended future finished wall thickness.


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## Tmac845 (Mar 20, 2013)

View attachment 97266


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## wingsfan (Mar 20, 2013)

your picture isn't working. Since your basement is not finished and you are going thru concrete, you sould be able to just make the hole big enough for the pipe to go thru. When you finish the basement then use a thimble around the pipe in the wall framing to keep your clearances what they sould be. To put a thimble thru concrete, you have to make a 14x14 inch hole for the thimble, and in my opinion that is not needed,


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## Tmac845 (Mar 20, 2013)

For some reason can't upload pics from phone, but that's exactly what I did.


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