Help with drafts around through window thimble

[presta24]

Growing up we had a big wood stove in the basement that we used to heat the house. Spent my youth being a cheap log splitter. Oddly enough, as soon as I went away to college, HVAC was installed and the stove was decommissioned. My family ended up buying the house I grew up in when my parents were ready to downsize. The old wood stove still chilling in the basement, long forgotten.

Fast forward, I have a makeshift office in the basement as I work from home 3 days a week. We have never had any heat or registers down here. In the summer its tits. In the winter its hovers around 55. Tired of the space heater so I moved the old stove to the other side of the basement, as the flu area was reclaimed for master bathroom space years ago, and a new roof omitted the old stack.

So I have run the stove pipe through a window box I built but it is very drafty and I am curious what I can do about that? The thimble I used was the one still in the basement ceiling from how it was hooked up before. I used 8" single wall pipe but there is a gap where it goes through the thimble and is obviously letting in drafty cold air. What can I use, if anything to insulate? Pics of move and thimble.

 

[kennyp2339]

You cant use single wall pipe for the pass through, single wall is ok for the inside portion as long as is meets the minimum of 18" from combustibles, for the pass through you'll need to use class a pipe and have it enter the living space up to the point were 18" minimum for the single wall clearance can be met. Once the class a is in, you can caulk around the pipe and shroud making it air sealed to stop the draft.
I'm concerned how the class a is installed on the outside, hopefully its to a T then substantially anchored so the vertical portion is secure from weather and gravity.

 

[presta24]

You cant use single wall pipe for the pass through, single wall is ok for the inside portion as long as is meets the minimum of 18" from combustibles, for the pass through you'll need to use class a pipe and have it enter the living space up to the point were 18" minimum for the single wall clearance can be met. Once the class a is in, you can caulk around the pipe and shroud making it air sealed to stop the draft.
I'm concerned how the class a is installed on the outside, hopefully its to a T then substantially anchored so the vertical portion is secure from weather and gravity.

I read online you can use single wall if you have the thimble. If no thimble you need the 18"

I have wall anchors for the outside.

 

[brenndatomu]

Never mind the draft, that's guaranteed work for the fire department right there...you need a proper "through the wall kit" with insulated class A pipe...that takes you down to 2" for your clearance to combustibles (CTC) instead of the 18" you should have there...there is just no way to safely go through there with singlewall pipe. You need a proper insulated class A chimney outside too...what's there now?

 

[bholler]

I read online you can use single wall if you have the thimble. If no thimble you need the 18"

I have wall anchors for the outside.

View attachment 307864

That is going into a masonry chimney. What chimney does this go into outside?

 

[presta24]

That is going into a masonry chimney. What chimney does this go into outside?

no chimney, just out and up the side of the house

 

[presta24]

Never mind the draft, that's guaranteed work for the fire department right there...you need a proper "through the wall kit" with insulated class A pipe...that takes you down to 2" for your clearance to combustibles (CTC) instead of the 18" you should have there...there is just no way to safely go through there with singlewall pipe. You need a proper insulated class A chimney outside too...what's there now?

Nothing, was going to run the single wall up. Why do I need the insulated outside? I get why I need it for the pass through. But why does it matter outside?

 

[brenndatomu]

Nothing, was going to run the single wall up. Why do I need the insulated outside? I get why I need it for the pass through. But why does it matter outside?

Because you need to maintain a minimum of 250*F inside clear to the top...if not the moisture (steam) in the exhaust stream will condense on the pipe walls causing creosote deposits...then when the chimney fire happens (and it will happen) the singlewall pipe will be glowing red causing any nearby combustibles (siding, framing, roofing, leaves, bird nest, etc) to catch fire.

 

[kennyp2339]

I read online you can use single wall if you have the thimble. If no thimble you need the 18"

I have wall anchors for the out

Diagram is for an existing masonry chimney, typically there is a clay thimble or "crock" sometimes there is none and a metal thimble can be installed like the drawing, but it terminates into a masonry chimney.
For your application this is not satisfactory and can be dangerous since clearance is not being followed (sill plate and window framing above)
A through the wall kit is needed because it balances out the center for the class a pipe which will automatically give the proper clearance, class a also only needs 2" from combustibles, once the class a w/ through the wall kit is installed you can seal up the air gaps with silicone.
A class a T is needed immediately on the outside then you can go straight up, if centered to the peak of the roof then go past the peak 2ft or you'll need to be 3ft higher then anything in a 10ft radius of the chimney cap.
FYI - single wall pipe is not allowed on the outside, performance wise.. it can work short term but will create tons of creosote, if there is a chimney fire, temps can reach upwards of +2100, which will cause fire extension to the structure. If you are unfortunate enough to have a fire, insurance will not pay out due to unsafe installation & no inspection, not to mention the safety aspect of family in a dangerous situation, and the first responders that also come to help.

 

[presta24]

Because you need to maintain a minimum of 250*F inside clear to the top...if not the moisture (steam) in the exhaust stream will condense on the pipe walls causing creosote deposits...then when the chimney fire happens (and it will happen) the singlewall pipe will be glowing red causing any nearby combustibles (siding, framing, roofing, leaves, bird nest, etc) to catch fire.

I understand. So no one uses single wall outside?

Diagram is for an existing masonry chimney, typically there is a clay thimble or "crock" sometimes there is none and a metal thimble can be installed like the drawing, but it terminates into a masonry chimney.
For your application this is not satisfactory and can be dangerous since clearance is not being followed (sill plate and window framing above)
A through the wall kit is needed because it balances out the center for the class a pipe which will automatically give the proper clearance, class a also only needs 2" from combustibles, once the class a w/ through the wall kit is installed you can seal up the air gaps with silicone.
A class a T is needed immediately on the outside then you can go straight up, if centered to the peak of the roof then go past the peak 2ft or you'll need to be 3ft higher then anything in a 10ft radius of the chimney cap.
FYI - single wall pipe is not allowed on the outside, performance wise.. it can work short term but will create tons of creosote, if there is a chimney fire, temps can reach upwards of +2100, which will cause fire extension to the structure. If you are unfortunate enough to have a fire, insurance will not pay out due to unsafe installation & no inspection, not to mention the safety aspect of family in a dangerous situation, and the first responders that also come to help.

Thanks for all the detail. I love forums. I use them for almost everything lol.

 

[presta24]

Sounds like I need to do a bit more research. Jumped in honestly just to see if I could move this stove as its a beast. Then snowballed into getting a fire in it asap. 100% was going to review code and all before I actually built a fire. But expected this to be a pretty simple and inexpensive way to get some heat down here. Need to revisit and see if its worth the investment. I could just knock a few vents in the existing HVAC feeder lines already down here. Or spend the coin to hook the stove up right Just not sure if its worth the trouble. We have a model 91 we use to heat the house. Unless its sub 20 and windy, the heat pump/Emergency heat doesn't run. We do have a 25x25 edition on the back of the house that is almost all glass. It is the first room to get cold. Burning the stove to heat the basement would likely help that. Like I said, I am already doing the work for splitting, stacking, seasoning, and hauling wood sooo.

 

[presta24]

Sounds like I need to do a bit more research. Jumped in honestly just to see if I could move this stove as its a beast. Then snowballed into getting a fire in it asap. 100% was going to review code and all before I actually built a fire. But expected this to be a pretty simple and inexpensive way to get some heat down here. Need to revisit and see if its worth the investment. I could just knock a few vents in the existing HVAC feeder lines already down here. Or spend the coin to hook the stove up right Just not sure if its worth the trouble. We have a model 91 we use to heat the house. Unless its sub 20 and windy, the heat pump/Emergency heat doesn't run. We do have a 25x25 edition on the back of the house that is almost all glass. It is the first room to get cold. Burning the stove to heat the basement would likely help that. Like I said, I am already doing the work for splitting, stacking, seasoning, and hauling wood sooo.

And to piggy back off this, I have a 1975 defiant sitting in the edition ready to go in, just waiting on a new roof to be installed when we get some nice weather. That would clearly nix the edition being cold

 

[brenndatomu]

My first stove was a freebie...it cost me $900 for the chimney parts.... free stove is like a free dog, no such thing.
Good to hear you are already working on your wood supply though, you'll need dry wood either way, and that doesn't happen quickly.

 

[kennyp2339]

I understand. So no one uses single wall outside?

Thanks for all the detail. I love forums. I use them for almost everything lol.

No problem, it took me a long while to get the hang of this stuff, well woodburning in general, still only know enough to barely keep myself out of trouble, but its a fun thing to learn and participate in. Good luck, and once you get the install squared away, watch out for the wood gathering addiction.

 

[sneefy]

Nothing, was going to run the single wall up [side of house]

This is an incredibly bad idea.

 

[begreen]

I read online you can use single wall if you have the thimble. If no thimble you need the 18"

I have wall anchors for the outside.

View attachment 307864

This is a misinterpretation. No stove pipe is permitted to pass-thru and continue through a wall or ceiling. Period. The section posted applied to connecting to a chimney, this is not the case here.

To do this correctly a class A (stainless) chimney system will be required with a class A thimble to pass-thru the window. Single-wall stove pipe is not permitted outside for a chimney. It cools down the flue gases too quickly, rusts out easily, and is a fire hazard.

It looks like the basement walls are uninsulated unless insulation in on the outside. If uninsulated, about a third of the heat produced will head out the walls into the ground. This equates to one out of every 3 cords burned. The old homebrew box stove will probably burn 50% more wood than a modern stove, so there will be losses there too.

 

[presta24]

This is a misinterpretation. No stove pipe is permitted to pass-thru and continue through a wall or ceiling. Period. The section posted applied to connecting to a chimney, this is not the case here.

To do this correctly a class A (stainless) chimney system will be required with a class A thimble to pass-thru the window. Single-wall stove pipe is not permitted outside for a chimney. It cools down the flue gases too quickly, rusts out easily, and is a fire hazard.

It looks like the basement walls are uninsulated unless insulation in on the outside. If uninsulated, about a third of the heat produced will head out the walls into the ground. This equates to one out of every 3 cords burned. The old homebrew box stove will probably burn 50% more wood than a modern stove, so there will be losses there too.

Yes, I was concerned about the old non cat stoves efficiency. The model 91 is a champ......and I remember being cold often with this stove heating the house in the winter as a kid lol