Guy at the fireplace store says our new stove set up won't draft

[doglover1918]

Hi Folks - I need your opinions, the more, the merrier. We are building a small house, and have bought a La Nordica Millie cook stove to go in one side of the kitchen. My husband stopped by the local fireplace/wood stove store to buy a couple of elbows to we could dry fit them before the roofers come back tomorrow. (They are in charge of the boot that goes over the chimney pipe, and we wanted to make sure the portion of the pipe that is inside the house was at the correct elevation above the floor.) Well, the guy at the store asked Mike some questions, and Mike drew a diagram of the set up. Then the guy said there is no way this will draft properly, and the house will be filled with smoke. This will be only our second wood stove, but we are careful people and not idiots. In my years of research I recall seeing many pipe set ups similar to our intended one. Do they all not draft? I have scanned Mike's drawing so you can see distances and heights. We wanted the chimney pipe to go out the center of the roof ring in the middle of the octagon because putting it to one side right above the stove would mean that we'd need several supports to steady it in our high wind area, and those kinds of supports don't work well with standing seam roofs. Thank you so much for any ideas you have.

 

[jetsam]

Hi Folks - I need your opinions, the more, the merrier. We are building a small house, and have bought a La Nordica Millie cook stove to go in one side of the kitchen. My husband stopped by the local fireplace/wood stove store to buy a couple of elbows to we could dry fit them before the roofers come back tomorrow. (They are in charge of the boot that goes over the chimney pipe, and we wanted to make sure the portion of the pipe that is inside the house was at the correct elevation above the floor.) Well, the guy at the store asked Mike some questions, and Mike drew a diagram of the set up. Then the guy said there is no way this will draft properly, and the house will be filled with smoke. This will be only our second wood stove, but we are careful people and not idiots. In my years of research I recall seeing many pipe set ups similar to our intended one. Do they all not draft? I have scanned Mike's drawing so you can see distances and heights. We wanted the chimney pipe to go out the center of the roof ring in the middle of the octagon because putting it to one side right above the stove would mean that we'd need several supports to steady it in our high wind area, and those kinds of supports don't work well with standing seam roofs. Thank you so much for any ideas you have.

View attachment 268285

It's likely that he's right. Not every stove will draft too poorly to work properly with 2 45s and a 13' rise, but a lot of them will. The vertical pipe will draft better with any stove.

A central location is also much better for heating- stoves are space heaters!

Do you plan to use the cook stove during the summer?

@SpaceBus, cook stove thread!

 

[doglover1918]

It's likely that he's right. Not every stove will draft too poorly to work properly with 2 45s and a 13' rise, but a lot of them will. The vertical pipe will draft better with any stove.

A central location is also much better for heating- stoves are space heaters!

Do you plan to use the cook stove during the summer?

@SpaceBus, cook stove thread!

In all likelihood, we will use it for the first few summers. The house is a high mass house, and we have 150,000 lbs. of insulated mass to heat to a uniform 75 degrees. That will probably take awhile. Thanks for your input.

 

[kennyp2339]

Summer cooking on that stove might be a bear with warmer outside temps, draft if affected basically at 50deg and above. If you do try to go that route, make sure you use dvl black pipe for the inside portion or you'll be a creosote factory, single wall will lose to much heat and gum up pretty quick.
Why not just go straight up and but the right roof bracing kit?

 

[jetsam]

If you're also cooking with wood in the summer, now you have a strong argument for keeping the stove near a window!

If you have roofers coming, it seems likely that a lot of your framing is done and you won't be open to changing the floor plan.

I guess I would probably go for a vertical roof penetration in the original location, if I was in those shoes. The mast support wires are all roof penetrations at one end, so try to get that sorted before shingling if possible.

Another (heating- and cooling-friendly) option is to move it to a central location, make it a regular woodstove, and put the cookstove on a covered porch. This solves your heating and cooling problems, but now you have two flues through the roof, one of which still requires a lot of support...

 

[doglover1918]

Summer cooking on that stove might be a bear with warmer outside temps, draft if affected basically at 50deg and above. If you do try to go that route, make sure you use dvl black pipe for the inside portion or you'll be a creosote factory, single wall will lose to much heat and gum up pretty quick.
Why not just go straight up and but the right roof bracing kit?

Going straight up puts the stove smack dab in the middle of the octagonal pod. This space is 27' in diameter, and has to contain the kitchen, a bathroom, and tv/reading space. It is the only place in the complex for a couch. With the stove in the middle, there isn't enough room for the seating. With the stove against a wall, we can "borrow" a bit of space from the kitchen half.

 

[doglover1918]

If you're also cooking with wood in the summer, now you have a strong argument for keeping the stove near a window!

If you have roofers coming, it seems likely that a lot of your framing is done and you won't be open to changing the floor plan.

I guess I would probably go for a vertical roof penetration in the original location, if I was in those shoes. The mast support wires are all roof penetrations at one end, so try to get that sorted before shingling if possible.

Another (heating- and cooling-friendly) option is to move it to a central location, make it a regular woodstove, and put the cookstove on a covered porch. This solves your heating and cooling problems, but now you have two flues through the roof, one of which still requires a lot of support...

Yeah, those pesky support wires don't work very well with a standing seam roof.

 

[SpaceBus]

I know you don't want to do supports, but that's what I would do in your shoes. Draft is everything on a stove, double for a cookstove. I have experienced a few marriage threatening incidents (mostly joking) with smoke filling the house due to a draft reversal. My stove goes through the wall with an exterior class A chimney, and 99% of the time I have no issues, but I only have 18" of horizontal run and no other bends. with a different stove I might have gone through the roof. Plan the roof penetrations well and use plenty of high quality sealant (DAP 3.0 has been the best I've found) and you won't have any issues with leaking. A couple of offsets can really wreck the draft on a 13' vertical run.

Congratulations on the La Nordica, those are nice stoves. If you plan on using the stove for your primary heat, don't expect a warm house in the morning unless you have a ton of really great insulation. My cookstove has to be packed to the absolute limit with sugar maple to still have coals in the morning, but my Morso can do that with softwoods with a smaller firebox. Modern cookstoves just aren't built to have super long burn times. We rely on the Morso to do the heavy lifting, but can heat the whole house with the cookstove in mild temperatures.

 

[SpaceBus]

Also, we use our cookstove in the summer when it's in the 50's and there is good air movement outside. Sometimes I do use the electric instant pot or range oven, but I try not to because food comes out of the wood oven much better than the electric. The wood fired cooktop is also much more enjoyable to use than the electric glasstop.

 

[brenndatomu]

That certainly won't set any draft records...might be hard to start from cold, sluggish on "warmer" days, and spill smoke while loading.
To have the best chance of working, make sure you use doublewall stove pipe...singlewall will lose too much heat and likely be a creosote mess.

 

[Corey]

I'm afraid I'd have to side with the fireplace store guy. Given your 9'4, 15' and 13' dimensions, that is a ~13 degree angle of rise, so your sketch is a bit optimistic on the rise of the angle. Most stove manufacturers will list a minimum rise / maximum run, but I imagine 15 feet at 13 degrees would fall outside that. So it would sort of be in the 'at your own peril' category, and I'd expect poor drafting, especially if you're looking at summer cooking.

The other issue is that it may 'run' fine, but start up and coal bed time may be an issue. Start-up is only a 'general' PITA, but if it stops drafting when the fire dies and only coals left, that is when you get a carbon monoxide back-up. So please get a good CO detector. (Should have one anyway - anytime there is a fuel burning appliance in the space!)

I have a stove in a ranch house and due to the location plus hip roof, the 'natural' chimney height is 13 feet straight up. Even that was a pain to get going on those ~40-50 degree days when I just want to chase the chill off the house and spilled smoke out the door. I added about 4-5 feet of insulated flue above the chimney and helped draft a lot - though still don't know how it would work for summer cooking!

If you 'have' to go the 'long run to the center' route, I would say insulate the heck out of the pipe or get the best insulated pipe you can. That will help keep heat in the flue, and aid draft. Extending the outlet further up above the peak, if possible, would also help. But still an uphill battle (no pun intended) at 15ft / 13 degrees!

Is there any possibility you could go through the wall and have a flue anchored from the ground? Or, heck, even set a post / pole in the ground as a support? That would keep your stove position at the perimeter of the house, provide support for a well-drafting flue, but still eliminate the issue of roofing support wires. Plus, extra headroom and no pipe across the ceiling!

Good luck with what ever you choose!

 

[doglover1918]

I'm afraid I'd have to side with the fireplace store guy. Given your 9'4, 15' and 13' dimensions, that is a ~13 degree angle of rise, so your sketch is a bit optimistic on the rise of the angle. Most stove manufacturers will list a minimum rise / maximum run, but I imagine 15 feet at 13 degrees would fall outside that. So it would sort of be in the 'at your own peril' category, and I'd expect poor drafting, especially if you're looking at summer cooking.

The other issue is that it may 'run' fine, but start up and coal bed time may be an issue. Start-up is only a 'general' PITA, but if it stops drafting when the fire dies and only coals left, that is when you get a carbon monoxide back-up. So please get a good CO detector. (Should have one anyway - anytime there is a fuel burning appliance in the space!)

I have a stove in a ranch house and due to the location plus hip roof, the 'natural' chimney height is 13 feet straight up. Even that was a pain to get going on those ~40-50 degree days when I just want to chase the chill off the house and spilled smoke out the door. I added about 4-5 feet of insulated flue above the chimney and helped draft a lot - though still don't know how it would work for summer cooking!

If you 'have' to go the 'long run to the center' route, I would say insulate the heck out of the pipe or get the best insulated pipe you can. That will help keep heat in the flue, and aid draft. Extending the outlet further up above the peak, if possible, would also help. But still an uphill battle (no pun intended) at 15ft / 13 degrees!

Is there any possibility you could go through the wall and have a flue anchored from the ground? Or, heck, even set a post / pole in the ground as a support? That would keep your stove position at the perimeter of the house, provide support for a well-drafting flue, but still eliminate the issue of roofing support wires. Plus, extra headroom and no pipe across the ceiling!

Good luck with what ever you choose!

Thank you for your (unfortunately for me) well reasoned response. I guess we will have to go straight up, and re-think the furniture layout. We can't go through the wall - the house is ICF construction - and even if we could cut through the rebar and concrete, the "outside" is not outside. It's an enclosed porch. Rats.

 

[doglover1918]

Thanks very much to all of you who responded. As soon as Mike came home with the news that our plan wasn't going to work, I knew that somebody (or several somebodies) would have good input for this question. I really appreciate it.

 

[jetsam]

Thank you for your (unfortunately for me) well reasoned response. I guess we will have to go straight up, and re-think the furniture layout. We can't go through the wall - the house is ICF construction - and even if we could cut through the rebar and concrete, the "outside" is not outside. It's an enclosed porch. Rats.

...enclosed porch is a good place for a cook stove that you will use in the summer!

In other news, did you guys notice that this thread started with "The fireplace store guy said...", and then everyone agreed with what he said? I think we broke some kind of hearth record here.

 

[brenndatomu]

Thank you for your (unfortunately for me) well reasoned response. I guess we will have to go straight up, and re-think the furniture layout. We can't go through the wall - the house is ICF construction - and even if we could cut through the rebar and concrete, the "outside" is not outside. It's an enclosed porch. Rats.

You can go through ICF...just need to hire a concrete cutting company to cut a hole for you...they will come in with a machine like this and it will take them about an hour to set up and bore you the most perfect round hole you ever seen...and then just use a "through the ceiling" kit for the porch roof, just like you would going through the house roof.

 

[peakbagger]

You can go through ICF...just need to hire a concrete cutting company to cut a hole for you...they will come in with a machine like this and it will take them about an hour to set up and bore you the most perfect round hole you ever seen...and then just use a "through the ceiling" kit for the porch roof, just like you would going through the house roof.
View attachment 268347

Definitely off topic but that photo reminds me of a project from my papermill days. We used a similar rig but upsized to drill a 30" diameter hole horizontally through a 100 year old concrete tank foundation that was a mix of concrete and granite. It was around 8' thick. the cutters were only 4' high so after drilling 4' they pulled the drill back and then wedged the edges of the saw cut to snap the 4' plug off. They then pulled the plug and slid the cutter back in the hole and kept drilling. The cutters were about 20K each. I was quite proud when I got to slide down the hole to get into the tank. Many folks I worked with didnt beleive it could be done.

To get back on topic, the draft will be variable, On a dark cloudy drizzly day it will not draft worth a darn, its clear dry sunny day or clear night it may draft okay.

 

[brenndatomu]

We used a similar rig but upsized to drill a 30" diameter hole horizontally through a 100 year old concrete tank foundation that was a mix of concrete and granite. It was around 8' thick.

Wow, that's quite the hole!
I've seen them snap off the plug on thinner walls too...same reason though, wall thicker than the cutter was long...

 

[Grizzerbear]

I've used one of them core drills before...and man let me tell ya......make sure your anchors for mounting the drill to the wall are tight tight lol. When one of them babies binds up in the wall it's no bueno.

 

[Corey]

Yes, I'd second the motion on the core drill. Easy to get through the ICF. I rented one for a couple hours to go through my basement foundation wall for flue pipe on a gas fireplace down there. Don't let ICF stand in your way!

 

[Morso1bo]

I’ve had my Milly for just over a year now and I love it. I always have coals in the morning after putting a few logs in it at 9pm. Here is my set up, always drafts well, even in 50 degree weather. Needs super dry wood to not have creosote issues! Heats very well. Hope my experience with the stove helps!

 

[doglover1918]

Definitely off topic but that photo reminds me of a project from my papermill days. We used a similar rig but upsized to drill a 30" diameter hole horizontally through a 100 year old concrete tank foundation that was a mix of concrete and granite. It was around 8' thick. the cutters were only 4' high so after drilling 4' they pulled the drill back and then wedged the edges of the saw cut to snap the 4' plug off. They then pulled the plug and slid the cutter back in the hole and kept drilling. The cutters were about 20K each. I was quite proud when I got to slide down the hole to get into the tank. Many folks I worked with didnt beleive it could be done.

To get back on topic, the draft will be variable, On a dark cloudy drizzly day it will not draft worth a darn, its clear dry sunny day or clear night it may draft okay.

That's a helluva story! Thanks for your opinion on the draft.

 

[doglover1918]

I’ve had my Milly for just over a year now and I love it. I always have coals in the morning after putting a few logs in it at 9pm. Here is my set up, always drafts well, even in 50 degree weather. Needs super dry wood to not have creosote issues! Heats very well. Hope my experience with the stove helps!

It is really nice to hear from someone who owns this stove, rather than just the folks who sold it. We are looking forward to having a stove again, after 2 years of living in an RV while we build. Although it will be just for cooking and ambiance (we have hydronic floors), we miss the fire.

 

[doglover1918]

Summer cooking on that stove might be a bear with warmer outside temps, draft if affected basically at 50deg and above. If you do try to go that route, make sure you use dvl black pipe for the inside portion or you'll be a creosote factory, single wall will lose to much heat and gum up pretty quick.
Why not just go straight up and but the right roof bracing kit?

Creosote is a concern because all we have here to burn is pine and aspen. Something to think about. Thanks.

 

[jetsam]

I've drilled dozens of holes through slabs and walls with Hilti core drills (flooded a motor pool by drilling a hole through a retrofit hydronic system that wasn't on the blueprints, too).

Diamond bits don't generate tremendous torque back on your end because they grind slowly and smoothly through then cement... but if the hole is a good ways in and the body of the bit binds (operator shifts the drill, usually), it will buck pretty hard counterclockwise. Unlike a saw, it won't go anywhere, the buck is rotational. Carbide bits are a slightly rougher ride at first but then it smooths out the first time you hit a big piece of quartz aggregate (because it stops cutting).

Back when I was doing it, the core bits (that's just the bit, not the drill) were in the $500-$1000 range for smaller ones (we used 2" or 3"). I imagine they are a lot cheaper now as industrial diamonds were mostly cast-off from diamond cutting then, and they are crunched into existence in a factory now.

AFAIK you can rent core drilling setups.

Remember to set up a dam on the floor inside; the process is water cooled. Think maybe a quarter gallon of water on the floor if all goes well, 5 gallons plus if you have issues. A shopvac will handle the water output with ease.

 

[brenndatomu]

Creosote is a concern because all we have here to burn is pine and aspen.

Not an issue as long as you only burn dry wood (20%, or less when measured internally)