ahjud, kaminad, pliidid, korstnad

It has been a slow spring here in Estonia (2010). This said, I think we can all agree that spring is actually here. Masonry work always slows down during the cold winter months for a variety of different reasons. I would like to talk about these different reasons.

The first is that during the winter, people already have their heat source fixed, whether new or old, what they currently have is what will be used during the winter season, even if the stove or heater is old and in somewhat poor condition. Heat is needed during this cold time and no one is thinking about tearing down their old heater to build when heat is still needed at that time.
Another reason is that it is just not physically possible to build using clay mortar in such cold temperatures. Clay mortar requires a warm temperature, most masons agree that a normal room temperature is the best for working with clay mortar. When then mortar or bricks are too cold, the process which initially sets the bricks is hindered or completely shut down.

So what are our options here in Estonia where we tend to have long and cold winters and building time is so short? The first thing that I would recommend, is to contact a mason early in the season, even at the end of winter and start discussing what project you would like done. As springtime nears, set a date to begin the work. Don’t just say that we will get together in the summer and build it then…..what happens is that summer, in fact comes, but then the masons projects mount up, time gets short, schedules fill up. Never think that it is too early to schedule a project date, at least then you will have a date set to do your project.

Another possibility is to schedule work to be done over the winter. Most masons will have more time in the winter, and if some precautions are taken, the work can be carried out. The first thing is to find an alternative source of heat while the over or stove is being built. This heat can be supplied by an electric heater for example. Of course the extra electricity will need to be paid for, but most masons will charge a little less during the winter months anyway. Once the stove is built, special care must be taken to ’cure’ or dry the oven out slowly with very low intensity fires. A series of small fires over a couple of weeks can dry the heater out thoroughly. Just don’t try to rush things here, as over-heating the stove at this point can cause its total destruction.

So, as summertime approaches, contact your mason and schedule a time to get that project completed. Waiting too long may mean trying to survive next winter with an unsafe heater.

I have so much to say about the Rocket Stove. First of all, it is a relatively new development in the history of stoves. I will focus more on rocket stove mass heaters.

Rocket stoves can be built inexpensively, really by anyone. People these days are focusing on making stoves better….and that usually means more efficient. We want to get more heat out of less fuel. The problem is how to do that. That is where the rocket stove comes in. The rocket stove was developed to more efficiently burn wood. It has been said that the rocket stove uses about 5 times less wood to produce the same amount of heat. The way the rocket stove achieves this is by burning the wood in a super-insulated chamber. The temperature in the chamber and into the next part of the stove called the ’riser’ is very high. This ensures the complete burning of the wood, even the gaseous part, which usually just blows out the chimney as unused and wasted fuel. In a properly built rocket stove, the only exhaust is CO2 and steam. The burn is so complete, that there is little waste or pollution of the outside air.

The main part of the rocket stove is connected to a length of piping which is usually covered with cob, a type of earthen plaster. As the heated air flows through these passageways, the heat is transferred to the cob. Then the heat is slowly released from the cob over the next day or so. The rocket stove is much lighter than a normal masonry heater, which makes it much easier to build and it normally does not require a heavy foundation. The rocket stove can also be built to release immediate heat from the barrel. Some of the heat is given off right away and some of it is stored in the cob mass for a more prolonged release. These types of stoves are ideal for people interested in saving the environment from harmful exhausts usually given off during combustion.

The rocket stove would be a great addition to any house being built in the ’Öko’ way. I hope to include some pictures so that the idea of the stove is clear.

Few things are simpler or more beautiful than a well built drystone wall. I used to wonder about these walls. How were they built? What were the techniques? I found out that there are no real tricks or secrets, just hours of strenuous, mind focusing work. Fortunately, that’s just what I like. When I was building these walls in Kentucky, I almost always worked alone, somewhere on a hillside or on the edge of a field or pasture. I like to work without gloves, to get a better feel for the stone. After a couple of days with bare hands on sharp Kentucky limestone, the hands would get extremely tender and then turn hard. It was best to just keep on working and let the hands toughen up.

Building a drystone wall is similar to assembling an intricate puzzle (except with heavy pieces). Every stone has its own place.The first important thing is to establish a strong foundation upon which the wall is built. The technique is not difficult but you should take the time to do a proper job. The rest of the wall’s weight will rest on this foundation.The next step is to build up the height of the wall. Here it is important to use the stones shape correctly and follow the 2 over 1 and 1 over 2 rule.Hearting, I found out, also plays an extremely important role in the strength and durability of the wall. Hearting- is the stone, or broken pieces of stone that are individually placed behind face stone and between both sides. The placing of these hearting stones is not at all random.Tieing the two faces together is another important aspect of the building process. Somehow the two faces of the wall need to be tied together. This can be partially achieved with the placement of each stone, but sometimes special through-stones are placed in the wall. Some walls are finished with a final course called ’coping’. These stones rest on the top to add extra weight to the wall and also to tie the two sides together. There are some minor differences between field stone walls and limestone walls, but the basic building principles apply to both types of wall.

What so much attracts me to this type of building is its simplicity-in material, tool, and process. I don’t know of many other types of work where you stand alone in nature, stone in hand, before your creation. Simple, nearing perfection.

It would be good, at first, to have an idea of what a masonry heater actually is and what it is not. A masonry heater is the combination of a firebox (built from firebrick-šamott), a series of pathways for the smoke from an intensely hot fire to travel to the chimney (with at least one 180 degree turn) built from masonry brick, and usually at least one shut-off damper to capture the heat. There are countless of these in Estonia and they go by the name of ’Ahi’.The šamott firebox is the place where the wood charge is burned, usually at a very high temperature. It is necessary to have a high temperature to achieve secondary combustion.

Secondary combustion is desireable since it is a much more efficient burning of the fuel and also measureably cleaner. A firebox where secondary combustion regularly takes place, has clean walls, meaning that there are no sooty deposits present. As the hot smoke travels through the masonry pathway on the way to the chimney, heat from the smoke is transferred to the surrounding masonry mass (bricks). These bricks then slowly release the heat over a period of time to the surrounding rooms.

A masonry heater can be a very efficient source of heat and is friendly to the environment. The key here is that the wood charge needs to be burned quickly and at a very high temperature. If these conditions are met, most of the energy stored in the wood can be transformed into heat which is then used to heat the home. If the fuel charge is burned correctly, at a high enough temperature, there is very little waste of the wood’s energy and little pollution is released to the outside air.

A masonry heater is not an open fireplace, nor is it a metal insert fireplace. It is important to understand that an open fireplace or metal insert fireplace is no where near as efficient as a masonry heater. It will not burn the wood charge efficiently, nor will the charge be burned cleanly. A fireplace as a rule burns at a much lower temperature and therefore secondary combustion is rarely achieved in any type of fireplace. Fireplaces are also quite a lot less environmentally friendly. This is just a general rule, and of course, may not apply to all metal inserts.

There are a couple of reasons for this. The first is out of concern for the environment.

Much of the plastics, magazines or other garbage have been manufactured using toxic chemicals. The burning of these materials releases these toxic chemicals into the environment, sometimes in an even more dangerous form than before.

I strictly discourage the burning of garbage, especially in your masonry heater. Besides releasing toxic chemicals into the environment, the burning of plastics and garbage can prematurely damage your heater.

These things do not burn as cleanly as dry wood and can leave very messy deposits on the inside of the heater.

It is just a better idea all around to stay away from burning garbage, especially in a masonry heater.

This is more of a safety issue really. Substituting a flammable liquid for proper fire lighting techniques is never acceptable.

Instead of this unsafe practice, why not instead take pride in a well built fire using properly dried wood?

The reason for this is simple. Once the heater is loaded with wood and set afire, the firebox will begin to heat up. And, if built correctly, should continue to heat up to the point at which secondary combustion begins to take place.

Secondary combustion is the burning of the gases contained in wood which takes place at a very high temperature. This is the most desireable type of situation for a couple of reasons.

1. The first one is that when the firebox is hot and secondary combustion is happening, it is then that the least amount of harmful pollutants are released into the outside air via the chimney.
2. The second reason is that when secondary combustion is not happening, only part of the fuel in the heater is being burned. The other part is just escaping out the chimney. It is like paying more for less fuel.

So, once the fire is lit, if at all possible, keep the heater door closed to keep the temperature in the firebox the highest that it can be so that secondary combustion can continue uninterrupted. This way your heater will burn efficiently and cleanly.

This tip is quite common sensical.  If there is any ember left in the ash that is being removed from the heater it is still a fire danger.  It is always a good practice to wait until the ash is cold before doing anything with it.  Regardless, it is a good idea to use a metal container when removing ash from your heater or cookstove.

Clean ash from a heater fire can be a good soil additive, so go out and spread it under your fruit trees (or on top of the snow under them!).

How much is too much?  For a  large heater, one that heats an entire apartment or 3 or more rooms in a house, no more that about 45 kilos of wood should be burned in a 24 hour period.  This amount of wood is usually burned in two cycles, one in the morning, one at night, somehwere near 8 hours apart.

The firebox should be filled with a load of wood and then set a fire and allowed to burn to coals without unneeded disturbance or opening of the heater door.  Any time the heater door is opened, the firebox temperature drops and secondary combustion (the very effecient burning of wood) can be undesireably stopped.  If once the first load of wood is burned and a second is added, the bricks in the heater will start to absorb more heat than they can radiate (give off).

If  bricks become supersaturated with heat they may warp or crack, which is obviously disadvantageous for the longevity of the heater.

The wood used in a masonry heater should be dry and seasoned for a number of different reasons.  The first one is for concern of the environment.  A masonry heater, if built correctly, should burn very efficiently, but this efficiency is only diminished when wet wood is used.  When the improper wood is burned, it cannot burn at the high temperatures needed to fully combust.  What this means for the environment is that harmful gases are being released into the air straight out of the chimney.

Another problem and potential danger is the flammable deposits being left behind in your heater and chimney, deposits that can ignite and cause a chimney fire.  Another problem worth mentioning is the decreased efficiency in heating your home.  When the improper wood is used, the heater cannot operate in the most efficient manner, which means the pocketbook will also be thinner.

Only properly dried and seasoned wood  can burn at the highest temperatures to provide the most heat for your home.