Fire!

Flames
The Tiny Cottage’s First Fire

“Fire!” Yelled Holly with glee! Finally we had heat in our tiny cottage. Two weeks ago to be exact since the lighting of our first wood fire. Ben promptly wanted to cook pancakes. It’s been a long time getting to this point and I wasn’t sure if we were going to have the wood stove installed before the winter was over. Fortunately the cottage keeps itself reasonably warm even in our winter.

Penetration Parts
Pipe Penetration Parts

To light a fire first we need a wood stove. Check! We got a cute little Vogelzang Boxwood Wood Stove last December 2006. Then we needed to seal the cottage up tight. Check – walls up, roof on, windows in, door done. Next I opened the chimney hole I had left in the top of thenorth wall over the corbel. That was breezy as the warm cottage air rushed out into the winter sky. To stop the flow of air, hold the pipes stead and provide a back form for the lightweight insulating concrete as we packed the space around the pipes – thus the pretty piece of 2″ thick pink foam with holes cut out above.

PVC Vent Pipes
Filling Vent Pipes

In addition to the chimney penetration there are a number of vent pipes that pass through this area to provide ventilation for the drain waste system, the kitchen and the bathroom as well as a conduit for future communications wiring if I need it. I wanted as many penetrations to be in the same place as possible. Many of them are ventilation related so rising in a chimney stack together works well. I went with a wall penetration for the chimney and vent pipes as it is easier to prevent leaks that way. I would rather not have water running down from the roof into the house. It is possible that I’ll put up a communications relay and the chimney will be our highest point so that also fits well there.

Before placing these penetration pipes I filled their ends with a bit of foam so we won’t be constantly losing heat. Some of them, most(?), won’t be used for a long time but need to be there when I’m ready so I don’t have to drill through the wall like we did in the kitchen.

Fire Clay Pipe
Chimney Pipe Sealed

Since it would take time for the insulating concrete to cure before I will want to lite the stove we also sealed up the penetrating stove pipe. This is a 8″ (~10″ outside diameter) fire clay pipe which protects the insulating concrete from the heat of the wood stove chimney. The insulating concrete protects the house structural concrete and the PVC vent and conduit pipes from the heat. A smaller diameter pipe passes through the larger diameter pipe.

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Vermiculite
Vermiculite

To make the insulating concrete we substituted vermiculite for sand using four gallons of vermiculite rather than three gallons of sand – this was by volume rather than weight. This created a mix that was 8:2:1 (Vermiculite:PortlandCement:Water) by volume. The goal is to create a lightweight insulative concrete that provides for thermal expansion and keeps the heat of a hot chimney away from the vent pipes and structural concrete of the house which could be damaged by excessive heat.

I find it is better to hand mix the vermiculite concrete than to use the mortar mixer which tended to break down the soft vermiculite making a medium density concrete.

What is Vermiculite?
Vermiculite is a natural mineral that expands with the application of heat. The expansion process is called exfoliation and it is routinely accomplished in purpose-designed commercial furnaces. Vermiculite is formed by hydration of certain basaltic minerals.
Wikipedia

In other words, popped rocks!

View Out Virmiculite
Virmiculite Packing

With Holly’s help on the outside we braced the pink foam form in place and foamed it along the edges to get an initial seal around the form. After setting the pipes in their respective holes I packed an outer layer of medium density concrete to stop mice and then the insulative concrete as tightly as I could, filling the cracks and crevices around the pipes. The insulative concrete is an interesting material – it feels very spongy when uncured.

Is Vermiculite Safe?
There is some concern with some older vermiculite products about asbestos. From what I’ve read this is not an issue with newer vermiculite. However, it’s dusty stuff so don’t breath it. Same as with portland cement, toner or any other fine dust. Once it is bonded into the concrete matrix I have no concern about it being a health risk. Our granite with its out-gassing of radon is probably more dangerous. The solution to pollution is dilution. e.g., Ventilate!

Pipes Placed
Pipes Placed in North Wall Penetration

Once the smaller spaces around the vent pipes were packed we placed the chimney fire clay pipe and packed more insulative concrete around that to separate it from the vent pipes. The reason for doing this in two stages was to better be able to fill the small crevices between the pipes. A packing rod is very helpful.

I wanted the plastic pipes well insulated from the potentially hot chimney thus the double walled chimney, the fire clay and the insulative low density vermiculite concrete spacing the PVC pipes away from the chimney penetration. Should the PVC ever get warm and outgass the system is setup so the gasses exit the house – these are vent pipes. I don’t want fumes coming into our breathing and living space. So far the PVC pipes have all been cold to the touch so it is working.

Stove Burn Off
Will Burning the Stove

While the ch
imney penetration cured we took the woodstove outside and burned it. When you buy a stove or pipe they come coated with grease. The grease stinks and I suspect it is not good to breath the fumes. So we set the stove up outdoors and burned a fire in it for a full day to degrease it. In addition to burning off the stove we also did each of the sections of stove pipe and the elbows. I’m very glad we did this because it stank to high heaven! I would not want those fumes indoors.

Stove Pipe Burn Off Fumes
Fumes off Stove Pipe

Here’s a photo showing the grease fumes burning off the stove pipe outdoors. The made the most interesting smoke rings rising up the pipe.

Hope Fire Tending
Hope Tending the Fire

Having a wood stove burning outdoors is a prime time to satisfy the urges of those little pyromaniacs in your life, er, I mean to teach your kids about how to tend a wood fire… Yes, that was what I meant!

Screwed Pipe
Stove Pipe Screw

To make sure that stove pipe sections don’t come apart in use I drill small holes and screw the sections together. I learned to do this back in the old farm house down the hill where there is a long horizontal section that tended to sag – well worth the effort. By the way, self-taping screws don’t. Looking at them I doubted it but the hardware store guy insisted they did. Pre-drill all holes at 1/2 the shank thickness.

Stove Pipe Outside
Stove Pipe outside

A view looking from the north side at the stove pipe exiting the top of the north wall of the tiny cottage. The pink foam form is still in place in this photo and it isn’t quite done at the time this photo was taken – e.g., the foil flap. The stove pipe is wired to the wall via bolts set in the concrete. There is fireproof fiberglass packed on the inside and the outside of the fire clay pipe around the metal pipe to provide thermal expansion and stop air leaks around the pipe.

Some interesting details:

1) We have about 18′ of stove pipe inside the house to extract the heat from the fire before it exits the chimney.

2) The total chimney height is only about 12′ of vertical head but it drafts very well, much better than the 30′ chimney on our old house ever did. This makes it easier to start fires and we don’t get back drafting and smoking – something I was concerned about with such a short stack since we had trouble in the farm house with this. This draft also serves to draw in fresh air through the floor pipes. Eventually that will work to power the air circulation system and the earth air pipes we’ll install next year like I had put in the old farm house which worked so well. Fresh air, especially in the winter, is important.

3) The metal stove pipe is hot but touchable where it exits the fire clay pipe in the north wall penetration but cool by the time it gets to the elbow however we’re not getting any condensation or creasote inside the pipe. That’s good news. It means the stove is running effiently and not wasting much heat to the environment. One improvement I plan to do is change the final elbow to a T so I can have a cleanout. That’s why I built the corbel down below the chimney. I’ll also put fire clay pipe up the exterior and do masonry around it to insulate it and further improve the efficiency of the draft. A project for another day.

4) The wires that hold the stove pipe in place sing with the wind. It is faint. When I am inside the house it sounds like I’m hearing distant cathedral bells. Quite pretty. It took me a while to figure out what was making the sound as it only happens when the wind is right – very often in the evenings and late afternoon. The wires are attached to anchor bolts that are embedded in the concrete of the roof which acts as a sound board. It gives me ideas…

Chef Ben
Chief Chef Ben Cooks First

Ben got to be the first person to cook on the new woodstove. He wanted to make pancakes for breakfast. Delicious!

Pancakes
Pancakes

Ben experimented with cooking the pancakes both in the skillet and directly on the woodstove top. The seasoned skillet is easier to flip from. I’m going to look into a flat griddle top as that may be more useful for our cooking needs most of the time. Anyone know of a source? I may endup having to make it as this stove is a bit of an unusual size.

Coals
Stove Coals & Wood

We’re able to easily build up a very nice bed of coals in the stove. This surprised me. I am used to our old Sam Daniels wood stove which is literally big enough for me to climb into – I’ve done so on occasion to patch and repair it. I had not expected the Vogelzang to hold a fire overnight – it’s not air tight – yet it does. This photo doesn’t quite do the stove justice – the entire bed of coals was glowing gently right then as I had added new wood for the evening.

The wood stove is inside a shroud of masonry which is thermal mass to soak up the heat of the fire. I did a lot of experimenting in the old farm house with adding thermal mass to our Sam Daniel’s wood furnace. It makes a big difference in how well a stove performs. Eventually my goal is to build a masonry stove on this base which will have ovens, larger cook surface, a smoking changer and be even more efficient.

Under the woodstove we put sand and bricks to protect the concrete pad from the stove. We also put sandin the bottom of the stove to protect the bottom plate of cast iron from the heat of the coals. In restrospect I think that might have been overkill as there is a nice bed of ash. But, it makes me more assured the bottom won’t crack.

Tuesday of last week we cut firewood, just two trees worth from the log pile that has been drying for a year. Will is to the point where he can lift and hold the chainsaw straight out from his shoulder at arms length – my measure of when one is ready to learn to use the big saw. He got his first lessons in blocking up wood. A milestone.

Carbon Monoxide Monitor
Night Hawk CO Monitor

Call me Nervous Nellie but I wasn’t comfortable until we had something up to make sure the stove wasn’t going to poison us. Smoke, Fire, Carbon Monoxide be gone. We’ve been running the woodstove for two weeks now and the CO monitor has read a steady zero.

Something that always bothered me about our old farm house is it is a neatly stacked bonfire ready and waiting to burn. Our new tiny cottage is made of concrete, granite, marble, glass, steel and aluminum – not very flammable. Even the contents aren’t likely to make much of a fire – We have very little possessions there, they
are stowed in trunks and they aren’t near the fire. It feels a lot safer not sleeping in a funeral pyre!

Outdoors: 9°F/1°F Sunny
Farm House: 57°F/47°F
Tiny Cottage: 58°F/49°F

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About Walter Jeffries

Tinker, Tailor…

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17 Responses to Fire!

  1. farmwife says:

    Iron Pots Depot has a variety of cast griddles at pretty good prices – lots of shapes.
    http://www.ironpotsdepot.com/category_Cast-Iron_Griddles_path_7113-10394-10412.html?source=adwords&keyword;=cast+iron+griddle&gclid;=CIeN7OOZhpECFQU6awodM1RfGw

    I’ve wanted that flat Lodge pan one for a long time — I should just order the thing!

    Congrats on getting the stove in and working good! I’ll have to take some pictures of ours — it was handmade by my FIL years and years ago. He used to sell them, and boy do they work well. Sometimes a little too well — I inadvertently got the house up to 87 degrees a couple of days ago and had to open all the doors!

    I told my hubby that we better not replace the old windows in this house or we’d die of heatstroke!

  2. Anonymous says:

    Walter,

    Really interesting post for me as I am installing a woodstove much like the Vogelzang (but over 100 years old) in my rustic farm cabin this spring. I, too will surround it with concrete and stone mass for heat storage (and protection for the wood walls).

    Have you tried making an insulating concrete using calcium aluminate cement (also known as Fondu)? It would be able to with stand the heat next to the chimney and could reduce the need for 2 layers of different cement mixes.

    Dave

  3. Liz says:

    Congrats on the wood stove! What an excellent first meal to cook with it.

    I have been looking for vermeculite to root some fig tree cuttings but haven’t been able to find it. Where did you get yours?

  4. Anonymous says:

    “Funeral pyre?!” I know we had often discussed the fire hazard of the old farmhouse, but I’m sure glad you didn’t use that term when we were still sleeping there. That gives me the heebee geebees. : )
    Holly

  5. Farmwife, thanks for the link. I’ll look through that.

    Dave, I haven’t ever tried the fondu cement but I’ve heard of it. I looked for sources of materials at one point but didn’t immediately find them and I did find the vermiculite so I went that way. I would still be interested in trying it. Many more projects to come. Do you know of a good source? I’m in Vermont – shipping is an issue if it ends up being of much weight.

    Liz, I’ve gotten vermiculite and perlite at local lumber yards and garden centers.

  6. karl says:

    we have a tiny fire box too. filler-up, half an arm load, and she’ll go all night. it helps to have a small house to heat.

  7. Anonymous says:

    Walter,

    I am building in southern Ontario, west of you as the crow flies. My sources would be expensive places to ship from, no doubt. The closest supplier to my farm is Merkley in Ottawa, great people but a long way from you. (www.merkleysupply.com/) Sorry, I don’t know anything about the US distribution.

    Dave

  8. HA, and I thought I was so awesome just for using a woodstove this year. This was a fascinating read.

  9. *grin* Wood heat is nice. Here are a few of tricks:

    Don’t clean out the ash too much. Let it build up and build a bed of coals in the ash. This helps to start subsequent fires and dry wood. It also makes fires burn longer and protects the stove.

    Dry the wood out by the fire before burning it. Warm dried wood burns much better, starts more easily and gives more heat. It also rusts the stove and chimney less since there is less moisture. We put the fire by the stove to dry. That is why there is a space under our stove in the masonry for wood. If you have an oven in your stove you can also put wood in there to dry although I wouldn’t leave it too long.

    Larger logs burn longer. This makes for less frequent trips to fill the stove. Our older cellar furnance lets us put in several big logs, (43″ long by 14″ diameter?) which will burn for a couple of days closed down or over night partly open. But, big logs are hard to start – get a bed of hot coals built before adding the big wood.

    Smaller logs burn faster and hotter. Great for starting fires and cooking at a higher temperature.

    Adding thermal mass to a stove will make more efficient and allow you to burn it hotter without losing as much heat. This also makes for fewer refill times and a cleaner chimney. This can be as simple as piling bricks or concrete blocks on and around the stove. Stones work too. Beware that the masonry and stone need to be thoroughly dry so it won’t explode – best to dry it gradually moving closer to the heat. Some stones like limestone may crumble from the heat.

    A longer stove pipe inside the house can act as a better heat exchanger grabbing more heat from the fire for you to enjoy. But, don’t get the smoke too cool or it will condense and form a lot of creosote & soot in the chimney. A balance.

    The stove pipe should stay within the insulated envelope of the house as long as possible so that it will stay warmer and draft better. Those pretty chimney’s built up the side of houses are less efficient than the ones up the center of the house.

    If you burn hard wood (maple, oak, etc all of which are more expensive) then it will burn for a lot longer than the softwood which is typically used in construction (spruce, pine, poplar, etc). On the other hand, the construction materials are free! :) Do be careful about burning things that will produce a lot of creosote, don’t burn plastics, etc. If you do burn high creosote woods (pine, spruce, etc) then burn them when they are drier (e.g., construction grade) and let them burn hotter to keep the creosote to a minimum. Also clean the chimney – it’s easy and basic safety.

    They don’t chip the construction wood and use it for landscaping because it is the wrong type of wood – it will rot quickly. Unfortunate. It does compost well and as you’ve found, burns well. Do watch out for creosote.

  10. David in MN says:

    Great post walter but why not a pellet stove? Then you just load it and go.

  11. pv says:

    I luv that top pix!

  12. Henwhisperer says:

    Look in antique stores or garage sales for Griswold, Wagner or Erie griddles. I’ve got a rectangular one and a round one. They work great and you can find them at reasonable prices in garage or tag sales. Don’t look on eBay though…just found out that my rectangular one is worth $185.00! Yikes. We found it in an antique store/ghost town in Texas for $35.00 and I made Vin haul it all the way home…lol.

    Henny

  13. Janet says:

    Awsome Walt. I love those smoke rings and am contiuasoul amazed at all that you and your family do. We ”built” our own house but what we mean is we hired someone to design it and someone to build it and then movers to move us in! You and your family really BUIT! your own house. Awesome! Keep up the great work and writing so we can all voyorstically live the good life. You remind me of the Nearings!

  14. I’m not incline to a pellet stove for a number of reasons:

    1) A pellet stove requires electricity – we get one to two weeks of cumulative electric outages and most of that is in the winter when we need heat.

    2) Pellets have to be bought – I can cut my own wood for free. Thus if I was burning pellets I would have to spend a lot of money for heat. I also would miss all those great workouts with the saw, hauling logs, blocking wood, splitting, etc. Then I would have to get a gym membership and drive to the gym – that takes time. :)

    3) A pellet stove would be bigger and not fit into the cottage as easily. It would also have a higher capacity than we need – this is a tiny cottage which heats very easily.

    4) In the long run I’m building an even better masonry cook stove which means the money ($1,000?) on a pellet stove would be a waste. The little stove we got was only $129.

    5) I’ve never used a pellet stove and would probably bungle it – all those dials and knobs. Rocket science. Very intimidating. :)

    Pellet stoves, like propane and oil furnaces, certainly make good sense for situations where you don’t want to have to feed the fire and are buying the wood anyways. I’ve been told by agents that insurance companies don’t like wood stoves because they have to be fed – they worry about which pipes will freeze in the house when you leave for a few days. I have an electric backup heater just incase but most of all our cottage simply does not freeze even in the coldest winter with out heat. Different tools for different situations.

  15. Anonymous says:

    for cooking with cast iron, “lodge” makes a two sided grill/griddle. That would work really well.

  16. mikerosss says:

    I think one of your advertisements caused my internet browser to resize, you might want to put that on your blacklist.

    • Do you know which one?

      Which web browser are you using?

      There is a bug in Internet Explorer 8 that is triggered by a javascript I use for sizing pictures. Microsoft has recognized the bug and patched it in Internet Explorer 9. This bug doesn’t show up in Safari, Opera or FireFox. See this post.

      Let me know.

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