I need help making a darn decision.

[GrumpyDad]

Im a new stove owner. It's not installed yet. Vermont Castings Dauntless if that matters.

I am building an expansion. I was proud of the layout and the work I've done so far until I realized I put the stove location dead smack in the center of a cathedral ceiling outside wall. And that's right, there's of course a beam straight above.

So I'm trying to figure out how I want the stove pipe to route. To get far enough from the roof ridge I figure Ill drop away and exit about 1 1/2 feet to 2 feet so I can get enough shingle under there and not get too close to the ridge vents. I'm going to use telescopic pipe for the vertical AND between the two 45 degree elbows to make the install easier.

<Here's my issue>. I searched and cannot find. Is there a rule for how close an elbow can be to the exit (chimney box in this case). Or is there a rule or standard for proper drafting for how far apart two elbows can be. For example having two elbows 6" apart might reduce draft more than having them say 29.5" apart? Or is that not a thing?

My goal will be to drop out of the ceiling box about 6" with a piece of double wall, then go to the elbow, use the adjustable piece to get around 30-33 inches in length before hitting the next elbow centered over the stove, then drop down about 80" to the stove adapter/stove.

 

[begreen]

The elbow can be attached to the cathedral ceiling support box if necessary as long as the clearances to combustibles (the beam?) are honored. With double-wall connector pipe, the clearance typically is 6" to the side and 9" to the ceiling. Be sure to secure each connecting joint with 3 screws placed at 120º intervals around the pipe.

 

[GrumpyDad]

The elbow can be attached to the cathedral ceiling support box if necessary as long as the clearances to combustibles (the beam?) are honored. With double-wall connector pipe, the clearance typically is 6" to the side and 9" to the ceiling. Be sure to secure each connecting joint with 3 screws placed at 120º intervals around the pipe.

hey thanks...but hmmmm 6" you say? I thought I thought of every clearance necessary but forgot about the pipe going into the cathedral ceiling box. How does one achieve 6" of clearance from the finished ceiling? The box only sticks out about 2" from the ceiling and from what I can tell (I don't have the parts in hand yet still in my shopping cart), the box isn't wide enough to keep the stove pipe 6" from the finished ceiling. The pictures I see of people exiting using a ceiling box, I don't really see where they are staying 6" away from combustible material.
I get what you are saying, don't have the pipe run up against a collar tie or beam closer than 6", but you made me think about how close the pipe will be to the finished ceiling side to side. Like if I took a tape measure and measure from the edge of the pipe to the edge of the ceiling box that isn't 6" if you get what Im saying.

 

[begreen]

Normally, the support box provides some shielding. By the description, it sounded like this was a cathedral ceiling. If so, was a cathedral ceiling box ordered?

If you can, post a picture of the beam and the proposed location for the ceiling box.

 

[GrumpyDad]

Normally, the support box provides some shielding. By the description, it sounded like this was a cathedral ceiling. If so, was a cathedral ceiling box ordered?

If you can, post a picture of the beam and the proposed location for the ceiling box.

It is a cathedral ceiling. I haven't ordered anything. I was originally going to go with a 24" box leaving a good bit of the box hanging down. However Im probably going to order the 12" box. The rafters are 2x12s on a 4/12 pitch.

A picture is worth a thousand words right?
You can see the little hearth pad on the floor. The stove won't be exactly centered. There is a piece of blue tape on the wall about 6' up that shows the route of the vertical pipe. Im probably going to have to install on the left hand side of the ridge beam because that will allow me to use telescopic pipe. If I go to the right side, I would have to put the pipe further down the roof and I didn't really want to do that. As this picture is actually facing almost direct south, the install for best venting would be better on the left side of the ridge vent as well.

 

[begreen]

Get an 18" or 24" box to make up for the roof slope.

Also, it looks like if the stove was corner installed, then the location might avoid an offset, though the hearth might need adjusting.

 

[GrumpyDad]

Get an 18" or 24" box to make up for the roof slope.
View attachment 297744

Also, it looks like if the stove was corner installed, then the location might avoid an offset, though the hearth might need adjusting.

Correct me if Im wrong, but I believe the ceiling box cannot protrude beyond the roof as that would interfere with the roof flashing. As Im using duravent, they make a 12, 24, and 36 (For deep extreme sloped A frame type installs)

Unfortunately I cannot do a corner install. I wanted to but then the hearth would extend outwards into the doorway of my little chill space to the right there, aka my office. I wanted everything to code for our safety and in case we resell. Local codes call strictly for 36" clearance and a heart size the size of Rhode Island. I finally got them to understand that a LISTED stove has parameters to adhere to, and that I was meeting them with my design. Well, until I changed the design to include elbows. I think I originally planned for that room to the right to be a bit smaller which would have let me go straight out. Whoops

 

[bholler]

Correct me if Im wrong, but I believe the ceiling box cannot protrude beyond the roof as that would interfere with the roof flashing. As Im using duravent, they make a 12, 24, and 36 (For deep extreme sloped A frame type installs)

Unfortunately I cannot do a corner install. I wanted to but then the hearth would extend outwards into the doorway of my little chill space to the right there, aka my office. I wanted everything to code for our safety and in case we resell. Local codes call strictly for 36" clearance and a heart size the size of Rhode Island. I finally got them to understand that a LISTED stove has parameters to adhere to, and that I was meeting them with my design. Well, until I changed the design to include elbows. I think I originally planned for that room to the right to be a bit smaller which would have let me go straight out. Whoops

No it can't go past the roof you cut the angle to match the roof.

 

[GrumpyDad]

No it can't go past the roof you cut the angle to match the roof.

thanks!

 

[moresnow]

If I go to the right side, I would have to put the pipe further down the roof and I didn't really want to do that.

Um. Why not?
I am trying to figure out why you would fight to get roof penetration on the left side of the ridge beam? Not to mention monkeying with the ridge cap/pipe flashing interference (potentially). The amount of pipe required above the roof penetration appears to make either side of the ridge beam irrelevant on a roof with that flat pitch. A hole in the roof is a hole in the roof. Put it where it's convenient and configures the connector pipe straight up and out. You will be glad you did when it comes to required pipe components, ease of cleaning, proper stove draft etc. Have you figured out what amount of chimney will be above the penetration to satisfy the stove's overall required venting length?
If I have misunderstood the issue, it would not be the first time Good luck.

 

[begreen]

Correct me if Im wrong, but I believe the ceiling box cannot protrude beyond the roof as that would interfere with the roof flashing. As Im using duravent, they make a 12, 24, and 36 (For deep extreme sloped A frame type installs)

Correct, it gets cut down to either flush with the roof or sometimes the excess is folded over and nailed to the roof.


Download the installation manual for the brand of chimney pipe that will be used. There should be more explanation on how to install there.

 

[GrumpyDad]

Um. Why not?
I am trying to figure out why you would fight to get roof penetration on the left side of the ridge beam? Not to mention monkeying with the ridge cap/pipe flashing interference (potentially). The amount of pipe required above the roof penetration appears to make either side of the ridge beam irrelevant on a roof with that flat pitch. A hole in the roof is a hole in the roof. Put it where it's convenient and configures the connector pipe straight up and out. You will be glad you did when it comes to required pipe components, ease of cleaning, proper stove draft etc. Have you figured out what amount of chimney will be above the penetration to satisfy the stove's overall required venting length?
If I have misunderstood the issue, it would not be the first time Good luck.

I can't go straight up I would hit the beam and the rafters. To force a straight up install, I would need to slide the stove over to the left multiple feet, and forward quite a bit. That would crush my ability to put a table and chairs in the area to the left.
So I have to exit either to left or right of beam. If I go to the right and I use an adjustable pipe between elbows the adjustable pipe has a minimum length requiring me to penetrate the roof further down from the ridge. I'm using 5' chimney pipe. I guess I could use two smaller sections however my stove was tested with a 15' draft and the 4' of approximate chimney pipe sticking out of the roof would take me to about that 15'. That right side is the front of the cabin. A four foot chunk of stainless sticking out of the roof will look odd. Wife will complain. If I go left of the beam only a couple of feet will be visible as that is the back of the cabin.

 

[GrumpyDad]

Correct, it gets cut down to either flush with the roof or sometimes the excess is folded over and nailed to the roof.
View attachment 297749

Download the installation manual for the brand of chimney pipe that will be used. There should be more explanation on how to install there.

Sounds like I need to get the 24, have some more exposed below and trim to flush above. It's been awhile since I cut myself with sharp metal burrs after using snips.

 

[begreen]

If you cut it flush, it will need to be boxed in under the roof so that it can be securely anchored to the box frame.

 

[begreen]

A four foot chunk of stainless sticking out of the roof will look odd. Wife will complain. If I go left of the beam only a couple of feet will be visible as that is the back of the cabin.

We have 7ft sticking out of the roof. The chimney not only needs to meet the stove spec, it also needs to honor the 10-2-2 rule.

 

[GrumpyDad]

If you cut it flush, it will need to be boxed in under the roof so that it can be securely anchored to the box frame.

right, I planned on having blocking opposite the run of the rafters so I can screw it in to 4 sides, likely 4 screws each side.

 

[GrumpyDad]

We have 7ft sticking out of the roof. The chimney not only needs to meet the stove spec, it also needs to honor the 10-2-2 rule.
View attachment 297751

My install will be like what you have pictured on the right. Except I will likely be about 4' out and 3'+ over the peak. Also within 10' and nothing else obstructing within 10 feet.

 

[begreen]

That will work.