This is what our fireplace looks like on the inside.
The fireplace and baffle system is built entirely from standard firebricks.
With the brickwork complete for the fireplace and side chambers, we are now beginning construction of the horizontal baffle system to extract heat from the exhaust.
Cardboard creates an expansion joint between the brickwork and the stonework.
The stonework is complete up to the arch. the white spots are beadboard insulation, which will later be cleaned out, leaving holes for pins that will hold the door in place.
Building the chimney up through the roof.
The completed masonry fireplace.
Build an authentic masonry fireplace with the efficiency of a masonry
stove! The baffle system in this fireplace extracts heat from the
exhaust, warming up the thermal mass of brick and rock. The masonry
fireplace can radiate heat for three days after the fire is out!
In this instructional video, Thomas J. Elpel demonstrates the step-by-step process of building a masonry fireplace, starting from the foundation and ending with the chimney. Elpel shows how to lay up the brickwork for the core of the fireplace, how to build the arch, and how to build the baffle system. With the brickwork complete, Elpel demonstrates freehand stone masonry, using natural rock to lay up the stonework around the brick core. DVD. 2012. ISBN: 978-1-892784-34-6. 108
Although I envision a world of houses so energy efficient that they need no heating system, I would not willingly give up my own fireplace. I like to stare at the flames and soak up the warmth on cold winter days, even when the house is already warm. Our fireplace is known as a "masonry stove" or "Russian fireplace," although the technology came from eastern Europe more than Russia. Most traditional masonry stoves have a solid metal door and function more like a woodstove than a fireplace. Ours has a glass door, and thus might be best described as a "masonry fireplace." I use the terms stove and heater inter-changeably, and fireplace to specify a masonry stove with a visible fire.
Masonry heaters are characterized by lots of mass to absorb heat from the fire, plus a snakelike flue to extract heat from the exhaust before ventilating to the outside. The masonry warms up slowly, then
radiates heat out for hours or days afterwards. I learned about traditional masonry stoves through an article in Mother Earth News magazine, about a masonry stove designed by Basilio Lepuschenko of Maine. I eventually wrote away for Lepuschenko's stove plans and studied them intently. Our initial house plans included only the wood cookstove in the kitchen, but later we built an addition to the house and we wanted an efficient fireplace for the new family room.
In Europe it was still common in the 1600s to burn open fires inside the house. Our forefathers built squared, wood-stucco houses with grass roofs before they built fireplaces or chimneys. The more advanced homes had a raised platform so the women wouldn't have to bend over to cook, and a few houses had plaster spark arrestors overhead. But the smoke flowed through the house and filtered out through the grass roofs or gable ends. The methodology was effective, but when one house caught fire it often took the entire town with it.
The reason builders did not embrace enclosed fires sooner was a matter of economics. A fireplace or simple stove with a straight chimney ventilates about 90% of the heat to the outside. More sophisticated heaters evolved during the "Little Ice Age," the period between 1550 and 1850 when the climate was unusually cold across Europe. Population increases put more pressure on firewood sup- plies, and tighter housing increased the fire danger. Safe, efficient heaters were developed out of necessity. Efficient heaters were made of thin tiles, cast iron, or heavy masonry, but all shared one characteristic - a series of baffles to extract heat from the exhaust.
Efficient masonry stoves gradually became popular across eastern Europe, but the idea did not carry over to this continent until recent times. The knowledge probably wasn't that common among early immigrants, and there was little need for efficiency anyway, since the New World was rich with free fuel. American pioneers built inefficient fireplaces and later metal stoves, followed by cookstoves with ovens. Energy efficiency was not an issue in this country until the fuel shortages of the 1970s. Inventors responded to the energy crisis by making "airtight" stoves. The air supply and exhaust in the stoves was tightly controlled, so the fuel slowly smoldered, giving off an even and steady flow of heat. Airtight stoves increased fuel efficiency to about 60%, but there were serious problems. Much of the remaining heat potential was released in the form of thick smoke, clogging chimney pipes and the atmosphere with unburned, cancer-causing particulate. The particulate built up in chimney pipes and often caught fire, sometimes burning down the houses.
Older stoves were less efficient, but at least they burned wood cleanly. The pollution problem in airtight stoves was eventually resolved with the aid of expensive catalytic converters to burn particulate in the exhaust. Catalytic converters increased the efficiency of airtight stoves up to 85% or 90%. Unfortunately, they wear out quickly, so the stoves get to be just as dirty as airtight stoves after a few years, unless the catalytic converters are replaced.
The energy crisis also led to a new interest in efficient masonry stoves. Several companies now offer pre-cast, laboratory-tested models as do-it-yourself masonry stove kits. Masonry heaters burn a hot fire with lots of oxygen, so the exhaust is very clean. A well-designed system extracts up to about 90% of the heat potential before the exhaust is ventilated out. The quality of these prefabricated units is exceptional, but the cost is astronomical-usually four to six thousand dollars for the core and hardware. Then you still have to add the stone or brick veneer and build a chimney.
Commercial units are expensive partly due to the refractory cement used to cast the pieces. Refractory cement is designed for use in high-temperature applications. The cement itself is different from the cement used in regular masonry, and it has bits of steel fibers and broken pottery pieces mixed in for aggregate. You could not buy the cement and cast your own blocks for much less than what you would pay for a factory-made unit. We wanted to buy a kit stove for our home, just to play it safe with the design, but the commercial units did not fit either the available space or our budget, so we designed and built our own.
Masonry stoves are built in many different shapes and sizes, and you can easily custom design one for your home. As with anything you build, the blueprint is the sum of the criteria. You have to list the
criteria, then brainstorm a plan that best fits the criteria. You will no doubt have some specific criteria for your unique situation, but for any masonry stove there are a few universal principles to consider.
A masonry stove needs a long enough baffle system to efficiently extract most of the heat from the exhaust, but not so long that the smoke doesn't immediately rise through the system when you light the fire. Without an engineering degree, success hinges on a bit of educated guess work. The total length of a typical baffle system is about 20 to 25 feet, in up-and-down or back-and-forth series. Our stove has about 20 feet of horizontal baffles, but it is difficult to compare since it is a split-flue system. The exhaust splits and travels horizontally through about 12 feet of baffles per side, but the baffles are much narrower, so the total surface area is greater. For greater efficiency, I believe we could have added another series of baffles on top (which would have made the fireplace unreasonably tall), or extended the baffles another brick or two horizontally. The Build Your Own Masonry Fireplace DVD details the construction of a second generation, improved masonry fireplace we built in another house. It is similar, but not identical to the masonry heater plans included in the sixth edition of Living Homes: Stone Masonry, Log, and Strawbale Construction.
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