Wood stove heat

I agree, I'm just trying to cover all the bases. The front half of the stove will be on a plywood subfloor, so it's this headache. I guess the more i read it if i leave the legs the same size, and use half blocks on their sides with the cores lined up, I'll be good. Am i reading that right?
 
Here's the pdf of the nfpa 211, aka if you are in the states this is what everything is usually based off of. It says with my 2" legs and unrated stove I need to put half blocks flat with the cores lining up, then metal on top, and I'll be good. So I'm trying to figure out if they really mean metal only, or can i tile over it cause that's gonna look like shit even if i used diamond plate. I can cover the cores with decorative metal mesh, but sheet metal is hard to make look good. I know it's overkill and a half, but if you don't install it right then they got you.

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Just an example. 6" clearance min for double wall and than 2 " clearance for the stainless steel (shiny vertical pipe). Working in the existing framing for the chimney sucked so I figured I would install the best I could afford at the time. There is also a pic of the pipe spec if anyone is interested.
It comes in 4ft length or smaller. Longer than 4ft and it would be dangerous to carry up a roof due to the weight.
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Cobleskill said:
What is the insulated hard liner made of?
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I used duravent duraliner for the rigid insulated liner installation. It's SS, high quality product
Cobleskill said:
I put a flex liner in my buds house after a roaring chimney fire. Did not really hurt the chimney but put the fear of god in them. Flue was huge for a fireplace. They had a slide in insert. Recipe for making creosote. Leaking air and oversized flue hard to keep up to temp. They put a new airtight in.
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Slammer install. Where a insert is slammed into a chimney and either straight vented into it or a short section of pipe more commonly jutting up into the chimney/smoke shelf. Super dangerous and illegal install in Canada.

DMc said:
Just the one stove, Justin. But as Burnham eluded to, the house was designed by us specifically to maximize the use of a wood stove.

It is a 1903 Hartland Oval that is UL-rated so house insurance will still accept it. A key component, is that it also has a outside fresh air intake into the firebox. With a tightly sealed house, this makes a difference.
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Great point to add to the discussion. A fresh air intake is required on all new installations in Canada regardless of the homes draftiness or not. Really a good idea.
I had thought for sure I'd seen a pic of another stove you had, must have been someone else's I suppose?
Tree09 said:
Thanks guys, I'll be going with the proper ss liner then. My next question is floor protection... so this is a non ul stove, requiring 36 inch side and top clearance, which with the addition of a heat shield for the mantle I'm good. Where I'm not good is on the floor... the stove has stubby 2 inch legs, which combined with the fact that it's not listed, requires a 4 inch masonry base or something. I'm still trying to figure out exactly what they are requiring on nfpa 211. Being welded construction, i could add longer legs, but I'm not sure which is the best way to go.

To further complicate it, I'm tight on clearance fitting in the fireplace in the vertical dimension. It's fortunately solid block, but if i raise the floor I'm going to have to cut out a row of stone, which means moving the lintel up, and gives me another 5 inches to work with. The floor is a few layers of concrete board with some tile on top, and it's ugly so it'll be good to change. I'll have to come out farther to meet the 18 inch requirement, which means doing some carpet work as well, but there's nothing i can do about that.

So basically I gotta figure out how to build this hearth, because that's step 1. I'm kinda surprised they are that anal over this, but i want it to be right and safe. This might take longer than I hoped to get it installed, but it'll be worth it. And yes, simply buying a new stove isn't going to be the way.
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Hearth requirements can get quite complex. If memory serves that hearth.com that I had mentioned has some really good resources/info on building hearths to the proper spec.


Patrick A. Selkirk is a top notch SS chimney. With double wall connecting pipe you are laughing, enjoying high performance efficiency and tight clearance safety!!
 
Tree09 said:
but sheet metal is hard to make look good.
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A laminated sheet metal perhaps, too industrial, but look at a cast iron plate, much more appealing. It's a bit thick, the edges are slightly rounded, and it takes a dark grey patina. It's a common product here since a long time. In my parent's house, we even made the fire directly on the cast iron plate, about one square meter, laid on 4 bricks at the corners. An other smaller one vertically shielded the fireplace's brick wall. Rustic !
 
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I have made my two underneaths out of old steel wagon wheels , crushed stone , flat stones , and concrete ... Does make it safer for front doors operations.
 
My gf's stove pipe is too close to the wall. She spoke to a former stove install inspector/ post fire-damage inspector.

She bought a sheet of stainless steel, some cement board and non-combustible spacers. Plans for a 1" (i think) air gap between drywall and cement/ steel.



My stove is far enough, but it roasts D's room through the wall.

I thought of something similar.

Thoughts?
 
SeanKroll said:
My gf's stove pipe is too close to the wall. She spoke to a former stove install inspector/ post fire-damage inspector.

She bought a sheet of stainless steel, some cement board and non-combustible spacers. Plans for a 1" (i think) air gap between drywall and cement/ steel.



My stove is far enough, but it roasts D's room through the wall.

I thought of something similar.

Thoughts?
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Seems like it would work. Shielding greatly reduces the temps of the wall behind it. I have some shielding in my basement stove install and I've monitored the shield temps and the wall behind temps(with a IR thermometer) and can't recall the numbers off hand but my conclusion was the shielding was very effective.

Scott, nice setup but it looks way short on the front, not sure how your codes are but I think Kyle was mentioning 18" same as ours extension on the front. I know there is plenty of variation between what is code and what works.
 
Squisher, when was the date for "new" regarding needing the fresh air intake in Canada?
 
squisher said:
Seems like it would work. Shielding greatly reduces the temps of the wall behind it. I have some shielding in my basement stove install and I've monitored the shield temps and the wall behind temps(with a IR thermometer) and can't recall the numbers off hand but my conclusion was the shielding was very effective.

Scott, nice setup but it looks way short on the front, not sure how your codes are but I think Kyle was mentioning 18" same as ours extension on the front. I know there is plenty of variation between what is code and what works.
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If I had it to do over again, I’d go a tile farther out. The stove loads from the left end or the front. We only open that front door a couple of times a year when there’s no fire to clean the glass.

I also have the option of sliding it back (letting the pipe go further into the thimble), but we get a good deal of heat off the pipe so I have it pulled forward currently.
 
And a stove techie question. Is there any data about draft as it depends on chimney length, outside temperature, flue temperature? I seem to notice way better draft on colder days. Also, is there an instrument like a small manometer to see how much vacuum you're creating via the updraft? I know there's flue temp meters but haven't seen draft(?) meters.

edit - found part of my own answer for a draft meter but I'd like to do an installed system of some sort - thousandths of inches of water!!! Ain't no home made manometer with a column of fluid gonna read that.
 
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Perhaps you have a hotter fire on the colder days?

It’s my opinion that a taller chimney will draw better than a shorter one, but that’s opinion only. No data to back it up. Drier wood will give the illusion of better draft, simply because there’s less smoke to pull. If you have an outside clean-out door that’s not closed well, the chimney will pull air through it, weakening your draft.
 
Hotter fire on a colder day cause my feed air (draft) is stronger, or stronger draft makes it end up a hotter fire. Kind of chicken and egg. Could see it either way. No cleanout, just a liner to the top.

I tried to rationalize it as gas temperature difference, like the hotter the air in a hot air balloon and the cooler the sky air the more lift, but I figured 10 or 20 deg C difference outside vs hundreds of deg in the pipe made the outside insignificant. Maybe I'm missing something.

Kyle, after back reading posts I might have some useful info for you. My liner was made in Quebec, can't remember maybe Montreal, and it had two claims to fame. One, it had titanium in the alloy for improved fire and corrosion resistance, rated for two or three chimney fires before it gaffs out. Two, it was designed 1/2" under or 1/4" under, can't remember, 6" so it could deal with slightly tweaked misaligned 7x11 rectangular clay liner tiles in an existing chimney for an easier install. And it's still technically a 6" liner 20 or 25 ft roll in a kit with twist on cap and upper/lower fittings to go right on your stove and brickwork. It was 200 to $250 when I got mine and a bit more when I did another install for a friend about 4 years ago.

edit - this might be the guys because they're quebec and have Ti alloy https://gmdistribution.ca/wp-content/uploads/2015/09/gmd_catalogue_feas_en.pdf and the price was at a contractor's outlet; retail (only used material) pricing was uniformly double, say at a stove store or via an installer. The kit was just in a big cardboard box. The cap part-turn twist locked on via one or two pins. No tools on/off for cleaning.
 
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It isn't really the temperature, but the density of air / flue that matters. The colder, the denser. The hotter, the lighter. The hight (vertically) of the chimney gives you the size of the gas's column affected by said density. I you rise the top of the chimney, you enhance the difference of weight between the gas's column and its equivalent outside. A strong fire does the same vs a coldish one. This gives a stronger movement since the things tend to come back to the equilibrium. The light column tends to go up like a bubble in the water, replaced at the bottom by the denser air. That should stop very soon, but the fire warms the cold air strongly, makes it light and adds its own hot combustion gas too. That maintains the difference in density and so the draft's engine. That's why the industrial chimneys were higher and higher back in the industrial revolution to get more and more power for the boilers and ovens. Now they are assisted by giant blowers so the size can be drastically reduced.
If the draft is strong, it provides a better supply of oxygen for the combustion, the temperature rises, more wood is broken down, giving more fuel for the fire, which needs more oxygen. But the higher temperature enhances the draft too and maintains the supply. Restrict either the air supply or the fuel supply (wood's quantity and /or wood's surface with massive logs) and you calm down the thing. The kindling at the beginning does the opposite with few wood (easy to heat) but a wide surface to be degraded. It gives a big supply of burning gas with a small investment in heat. That allows a small but nice fire which heat the air in the chimney and starts the draft engine. The chimney isn't really needed, but it's a nice improvement inside. Out side, you get exactly the same effect in the open air: more fire, more heat, more draft, more fire. But If you aren't able to restrict the fuel supply, you end up with the tornado fires devastating the australian and californian forests.
 
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Kyle,
How is the stovepipe/stove install? I had a simple downdrafter for years. Vermont- made, got it inexpensively. A ceramics professor at the university needed tree work. I partially traded for new fire brick. I gave him the dimensions and he made and fired the refractory brick for insulating the bottom and sides. That stove would hold a bed of coals a long time.
 
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It's going, i had another treatment, so that was 1 week in the hospital and just now I'm starting to feel better so i hope to work on it soon. I've got a couple buddies ready to help too, so hopefully I'll be able to knock it out this round. I got everything all planned out, and will likely order the chimney liner tomorrow. The floor I'm going to just do the blocks and cheap sheet metal for now, which will make it legal and safe. I gotta take off one course of flagstone block off the top of the fireplace and replace the lintel. The stove itself will have a few cracks repaired, the homemade water tank on top cut off, cleaned up and painted, and I'll even test run it outside to burn the paint in and make sure everything is good. Then when the liner gets here I'll hack apart enough of the metal fireplace as needed to get it installed, and cement the bottom off.
 
I saw on This Old House I think recently where they put mesh in the old fireplace where the damper used to go. Then they troweled some kind of mortar over the mesh to seal it to the liner and close the chimney off.

Actually I think it was right at the beginning of the flue where they meshed around the metal liner.
 
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I got my double wall order in yesterday for my latest wood stove install. $1200 for black pipe to first floor ceiling and then 19 feet of stainless double wall. Still waiting on the attic insulation guard to come in but got the rest. I can get going on the project. Have a smaller Avalon in the kitchen (old farm house.) It keeps that room nice and the living room somewhat. We took wall out from living room to next room and new wood stove is going in there. Pretty central. Got an old circulator in good shape for this year. I ran one like it for 20+ years. Not highly efficient but they take a good sized chunk and keep a fire for 8 hours. Bimetallic thermostat kind of keeps an even fire without a bunch of fussing with it. They still sell similar models new but I am looking for something better down the road.
 
When I lined my chimney it was a bit of a pain. The Terra cotta liner is rectangular and the 8” round liner was wider than the shorter dimension. The evening before I installed it I laid the liner on a 2x10 on the ground, another one on top and stood on it to ‘ovalize it’. Worked my way up the full two and a half story length of it and it turned out really well. Dragged a work light through it after dark to be doubly sure I hadn’t popped any seams of the coil apart. Clamped it to a cone with an eye bolt through it and pulled it right up. Added to the bottom a section of pipe and an 8” T- section with a cap on the bottom for ease in cleaning and the pipe to the stove out the side.
 
Pigwot, when I got my first (for me) liner the guy mentioned the ovalising approach and alluded to concerns about munging the crimp seam. This was apparently the impetus for the tad under O.D.ed liner product. I would wonder a bit about the effect of oval on fitted or rotary cleaning brushes. ?

Here's a topic revisit - automatic air/draft control devices. The same guy has a video with a Condar unit and apparently the other one was Sotz. Both seem to not be sold anymore. Anybody know the story on this topic?
 
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