Can this be done? Running two 6" flues in the same Chimney flue.

[k3c4forlife]

I just bought my first house. I have a fireplace and a wood burning stove. A long while back, the garage was converted to a den and the wood stove was added to the back of the fireplace chimney. It is definitely not to code. A 6" hole was drilled into the back of the chimney and the wood stove flue was inserted into the chimney and cut. The flue was then plastered around with high temp grout.

I have been running the wood stove while I am home with very close inspections every hour or so for the last 2 weeks just to make sure everything is running ok. There hasnt been any problems yet, but I definitely cannot reach the full heat output potential of my stove because of the sketchy installation.

Here is what I want to do: I cannot run the fireplace at the same time as the I would like to buy an insert to put on the fireplace side so I can get more heat directly into the center of the house. The chimney has a 12" x 8" flue that runs up approximately 20'. I would like to run two separate 6" flues within the 12"x8". They should both fit if I put them in opposite corners.

This would drastically increase the safety of my wood burning stove and allow the use of both the stove and the insert at the same time. Is this a good idea or a terrible idea? Would the two 6" flues need liners? I'm sure I will get torn apart for this one...

Thanks for all your comments in advance,
Kevin

 

[heffergm]

I know nothing about what code specifies in a case like this. But ican say this: after watching my 6" liner getting
installed in my 12x8 flue I seriously doubt
you have a prayer of getting two liners in there. Assuming of course it's safe to do, which I think common sense will say it's not, nevermind building code.

It might make sense to call the building
inspector and have him take a look. Was the house inspected before you bought it?

 

[webbie]

I also doubt that you can get two flues into that liner. The inside of such a flue is about 7" by 11". Opposite corners won't do much.

 

[k3c4forlife]

I did have it inspected, I knew it wasnt to code when I bought the house but it was a steal for NJ.

 

[slayer7]

Ditto on code and size issues. I have the same size flue as you (8x12) which is really about 7x11 on the inside and effectively much smaller still because of the mortar remnants between the flue tiles. My installer had to ovalize the (one) 6 inch liner in order for it to fit. IMO it would be physically impossible to ever fit 2 of them in there besides being most likely against code and possibly hazardous. Maybe you could just run the stove pipe straight up through the garage roof and have the insert use a liner in the chimney.

 

[k3c4forlife]

That is my second option. It would be cheaper for me to share the flue. I need to go home and measure the chimney flue to make sure its 12" x 8" I remember thing eh, two will fit. Maybe it's the next size up. Is it OK to have the outside of the two steel flues touching each other if they were both running? I want to know what the code is...

 

[cycloxer]

You need at least 13". The 6" liners are not exactly 6". They are more like 6.25-6.5" because they are not perfectly round & straight and they bend all over the place. Even with 13 or 14" it will be challenging to get two liners in there. Maybe if you try and push both of them in at the same time you have a chance.

I know trying to put a 6" liner inside a 7" flue required some effort.

 

[k3c4forlife]

Assuming I can get two flues through the chimney flue, is this something that you guys would consider safe? I think its definitely safer, but I dont know if there are rules against flues touching each other, etc.