Wall Thimble Install

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Hulltm427

New Member
Nov 11, 2020
5
Alaska
So I bought a pellet stove and I want to install it in my split level home. I want to put it in the lower level but the first 39” of wall is solid concrete. That being said I want to install it with the pipe at the lowest possible level exiting so there isn’t a ton of pipe running up the wall inside then exiting to the outside. It’s in a corner and I wanted to know if it was okay to have the inner portion of the thimble contacting a stud. The marks to the left of the pipe are a stud or if that’s a fire hazard and it needs to be centered between the two studs somehow. Also how much pipe should I run vertically outside?
 

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johneh

Minister of Fire
Dec 19, 2009
4,377
Eastern Ontario
Hulltm427 welcome to the forum
Your installation manual will give you the information
you are looking for. Also, check with your local Gov. for
any bylaws they may have. See to your inspector for any
insight he may want with your installation. Also, the make
of your stove would be helpful in guiding you.
 

Hulltm427

New Member
Nov 11, 2020
5
Alaska
Hulltm427 welcome to the forum
Your installation manual will give you the information
you are looking for. Also, check with your local Gov. for
any bylaws they may have. See to your inspector for any
insight he may want with your installation. Also, the make
of your stove would be helpful in guiding you.
Hulltm427 welcome to the forum
Your installation manual will give you the information
you are looking for. Also, check with your local Gov. for
any bylaws they may have. See to your inspector for any
insight he may want with your installation. Also, the make
of your stove would be helpful in guiding you.
I have included a few pics in the response and the information is pretty vague on the type of installation I am attempting. Also Ill be forward in telling you that Alaska has very loose standards and codes as far as building and they are very difficult to interpret.
 

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SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
One word........NO.
 

Hulltm427

New Member
Nov 11, 2020
5
Alaska
Well I got the issue with clearance cleared up. Now there is issue number two, from the inner wall to the outer is 18” plus so how do I make the thimble work as it only goes to 12” fully extended. Can I add something to the middle or what’s the deal?
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
Well I got the issue with clearance cleared up. Now there is issue number two, from the inner wall to the outer is 18” plus so how do I make the thimble work as it only goes to 12” fully extended. Can I add something to the middle or what’s the deal?
Go to the hardware or a box store and get yourself a sheet of light gauge galvanized and a pop rivet tool and extend the inner to whatever length you need. So long as there is about a 1" overlap between the outer and inner, you are good to go. Had that issue myself when I put mine in. Our old farmhouse has 2 x 12's for studs in the wall I went through so the collars would not overlap. I extended. All the thimble does is provide an air break between the vent pipe and combustible surfaces. The air break is the space between the vent pipe and the thimble wall.
 

Hulltm427

New Member
Nov 11, 2020
5
Alaska
Go to the hardware or a box store and get yourself a sheet of light gauge galvanized and a pop rivet tool and extend the inner to whatever length you need. So long as there is about a 1" overlap between the outer and inner, you are good to go. Had that issue myself when I put mine in. Our old farmhouse has 2 x 12's for studs in the wall I went through so the collars would not overlap. I extended. All the thimble does is provide an air break between the vent pipe and combustible surfaces. The air break is the space between the vent pipe and the thimble wall.
I figured that may be the alternative but I wanted some input first. Thank you so much for your time and effort it is greatly appreciated.
 

Capy01

New Member
Jan 12, 2022
8
Meredith NH
Go to the hardware or a box store and get yourself a sheet of light gauge galvanized and a pop rivet tool and extend the inner to whatever length you need. So long as there is about a 1" overlap between the outer and inner, you are good to go. Had that issue myself when I put mine in. Our old farmhouse has 2 x 12's for studs in the wall I went through so the collars would not overlap. I extended. All the thimble does is provide an air break between the vent pipe and combustible surfaces. The air break is the space between the vent pipe and the thimble wall.
Have the same issue. Would you insert the new extension inside the existing inner and pop rivet to the inside of the inner or would it be easier to pop rivet to the exterior of the outer and extend that? Really hard to find any guidance on this topic. Even the extension that they make has no info on if the extension goes inside or outside of the existing wall thimble. Any help is much appreciated..