Single Wall Pipe Clearances

[mustardman]

Hi All,

I am installing a stove. (Quebec). I would really like to install a single wall chimney up to the attic. I know clearances to combustibles is 18 inches standard, but what I would like to know is if I can reduce that clearance with non combustibles. I would rather not install the half circle heat shield nor a double wall pipe.

Thoughts?

 

[pen]

I believe these are Canadian specs http://woodheat.org/flue-pipe-installation.html

According to the site:

1. Minimum clearance from combustible material: 450 mm (18 in.). The minimum clearance may be reduced by 50 percent to 225 mm (9 in.) if suitable shielding is installed either on the pipe or on the combustible surface.

I don't have specifics on what it takes to make "suitable shielding" for Canada handy but it sounds like it is possible.

Are double wall pipes out of the question?

pen

 

[Holiday]

Why not just use double wall and be done with?

 

[begreen]

We need a clearer picture here. Is the pipe penetrating a ceiling and then directly in the attic, or is it going through another floor first, then the attic?

 

[mustardman]

I have only a one story house. The pipe is just going to be about 7 feet long and going into the ceiling which is the attic. I bought all the proper insulators and fittings to go through the attic.

 

[DAKSY]

Where are you needing the clearance reduction? Between the connector pipe & a wall behind the stove? Is that small Jotul (Your Avatar) the stove that you are intending to install? Can you post a sketch(or pic) of the existing conditions to give us an idea what you're dealing with?

 

[oldspark]

So is this a cost savings for you, the double wall is for clearances so if you are having problems with clearances it makes the most sense does it not?

 

[mustardman]

Hi Daksy,

It is the pipe from the internal wall. Here is an idea of where I am going to be installing it. It is the pipe than I need to bring less than 18 inches from each of the back walls behind.

Have a look and tell me what you think.

 

[oldspark]

Any shield you make is not going to look as good as the double wall pipe correct?

 

[DAKSY]

Hi Daksy,

It is the pipe from the internal wall. Here is an idea of where I am going to be installing it. It is the pipe than I need to bring less than 18 inches from each of the back walls behind.

Have a look and tell me what you think.

If that is the condition of the location, I would remove & space the Perambase 1" off the wall & leave a 1" gap at the bottom & top for air convection. That way you'd have the clearances built into the surround. Either that, or you could add a second layer of Permabase spaced 1" out & then apply your finish to that.

 

[oldspark]

So far looks good.

 

[mustardman]

thats exactly what I am trying to do is build the clearances into the surround. I know that the double wall pipe is my worse case scenario, but I am worried that I am going to lose a lot of heat. SIngle wall pipes allow for better heat IMO

 

[oldspark]

thats exactly what I am trying to do is build the clearances into the surround. I know that the double wall pipe is my worse case scenario, but I am worried that I am going to lose a lot of heat. SIngle wall pipes allow for better heat IMO

Yea some, I have single wall and others have said they like it better even to the point of changing out the double wall back to single.
Sounds like Daksy gave you some good advice for what you want.

 

[DAKSY]

If you ran the steel mounting for your Permabase in a vertical direction, you would probably meet the criteria for clearances. You would STILL need a 1" air gap top & bottom. That would allow for plenty of cooling, convection air flow

 

[mustardman]

Thats what I thought. I was hoping that it would still work as heat can still escape out the sides. The permabase is away from the wall. I am also putting ledger stone all the way up which will help as well. In your opinion will the permabase pass inspection. I have read a lot of mixed reviews of the use of Permabase for behind wood stoves.

 

[Todd]

I know that the double wall pipe is my worse case scenario, but I am worried that I am going to lose a lot of heat. SIngle wall pipes allow for better heat IMO

Look up Security double wall pipe, it has slits in the outer layer which allow some heat to escape from the double wall.

 

[DAKSY]

Thats what I thought. I was hoping that it would still work as heat can still escape out the sides. The permabase is away from the wall. I am also putting ledger stone all the way up which will help as well. In your opinion will the permabase pass inspection. I have read a lot of mixed reviews of the use of Permabase for behind wood stoves.

It won't meet code that way. The supports need to run from floor to ceiling (vertically). I know it's a PITA to have to redo that, but it's either install that bracing & layer correctly, or add another layer. Either that or you use an approved pipe shield...Your call.

 

[mustardman]

I think I am going to install the bracing layer properly. I do not like those heat shields. Is Permabase approved?

 

[mustardman]

I am just not sure how much heat I will lose. I have heard that it is more difficult to heat using a wood stove with double wall pipes. plus they are about 4x the price of single wall.

 

[oldspark]

I am just not sure how much heat I will lose. I have heard that it is more difficult to heat using a wood stove with double wall pipes. plus they are about 4x the price of single wall.

Not sure if that would be a big issue, as BG states it is the stove doing the heating not the pipe of which I agree to an extent, I had no problem with clearance and no way was I going to spend that much money for the double wall, but the best single wall aint cheap either.

 

[DAKSY]

After reading this:

https://www.hearth.com/talk/threads/cement-board-research.7445/

I might be a little hesitant to use it...

 

[mustardman]

I know, I read that as well last night. The only problem is I already bought it and I dont want to wast 100$ if it is still good. I am still putting a whole layer of ledger stone on top of the permabase.

http://www.homedepot.ca/product/6-inch-x-24-inch-dorada-ledgestone/969571

 

[mustardman]

TO be honest I only saw the single wall that was 20 or 30 bucks a section.

 

[oldspark]

This is on sale but shipping is a bummer, maybe better deals out there, its 22 gauge and there are more brands that are as good or better, did not want to go with the thinner stuff, have some 30 year old 24 gauge that looks new for the most part, amazing what burning dry wood will do for ya.
http://www.amazon.com/HeatFab-Single-Wall-Black-Stovepipe/dp/B002078SKU

 

[mustardman]

wow, good quality single wall is still pretty expensive