ROTHSCHILD HEATER
This article first appeared in Fine Home Building
in September, 1992, issue #76. We have added to it several more
drawings and photos to show the full layout of the heater and
a view of the exterior of the house.
Small House, Big Heater
Viola Rothschild was 79 when she moved into her new center-chimney
cape on wind-swept Tory Hill in Strong, Maine. She previously
had lived for 47 years in Bangor. But when her mother died at
the age of 102, Viola asked her son Michael what she should do.
Michael said that she should move to Strong, where he and his
family would build a house for her within sight of their 18th
century Federal farmhouse.
Michael paced the fields across the road from
the farmhouse, relying on his heart and his artist’s eye to tell
him where Viola's house should be. He called and wrote to architect
friends, inviting comment and design ideas. He also called on
me, an old family friend, for advice. We had worked together before,
having fashioned with the help of his family and friends a handmade
soapstone complex consisting of a fireplace, a bake oven, a cookstove,
a bench, shelves and a sink. That masonry centerpiece transformed
a new timberframed wing off the farmhouse into a family room for
banquets, violin and piano concerts, ping-pong tournaments and
art shows.

But that wasn't Michael's only experience with masonry heaters.
Michael had just returned from several months of lecturing on
art and sculpture in the People's Republic of China. During the
tour, he and his son Harry visited a remote village whose houses
were carved out of stone cliffs. Inside one house, Michael and
Harry were surrounded by three or four generations of bright-eyed
villagers who had never seen the likes before of this large, dark-haired,
white American or his larger, red-haired son. The two men were
invited to sit on a wood-heated, carved-stone bed-bench-table
called a kang, probably the most ancient form of masonry
heater known. Inspired, Michael decided upon his return from China
to build Viola’s new home around a wood-fired masonry heater that
would include a heated bench to give comfort to her arthritic
joints.
The Cape Cod style of house was born in the
Massachusetts Bay Colony during the late 17th and early 18th centuries.
A hedge against the blustery weather of the Cape, the traditional
version was one story high and two rooms deep, with a symmetrical
facade and a steeply pitched, side-gabled roof for maximum headroom
on the second floor. Communal rooms (foyer, living room, parlor,
kitchen and pantry) were placed on the first floor, and bedrooms
on the second. All the rooms were comfortably arranged around
a central fireplace and chimney of stone, brick or both. A pair
of stairs--a main one in the foyer and a utility stair in the
kitchen--united the first and second floors.
We decided, with Viola, to build a personalized
cape. The house frame would include four timber-framed bents (complete
sections, or gable-end profiles, of the house that consist of
two or more posts linked by horizontal girts and supporting a
pair of rafters). The two center bents would be spaced about 11
ft. apart, sufficient for accommodating a substantial masonry
heater. Like its forebears, the heater would provide thermal mass,
fire-viewing, heating and cooking. We would, however, seek our
design inspiration from Finnish and Chinese roots rather than
American. Finnish masonry heaters, in particular, are known for
their exceptional flexibility, efficiency and heat-storing capability.
They also burn cleaner than any other type of fireplace or wood
burning appliance available, including the latest wood stoves
rated by the Environmental Protection Agency. Besides, for years
I have designed, built and conducted workshops on Finnish-style
masonry heaters, so I was on familiar turf. Finnish heaters can
be finished in stone, tile or brick. The Rothschilds picked brick
for a traditional look.

Respecting Viola's age, Michael and I devised a floor plan that
would allow her to live almost exclusively on one floor. On the
first floor, a kitchen, a dining room, a living room, a bedroom
and a bathroom all pinwheel around the masonry mass. We also tucked
a laundry room into the northeast corner, where it is warmed by
convection and by heat from the laundry appliances. A fully enclosed
14-ft. by 16-ft. sunroom is attached to the east gable end.
The bathroom lies between the foyer and the
back of the masonry heater, displacing the traditional main stair.
This layout called for an unusual hallway into the house. A traditional
centered front door opens into an ample foyer flanked by a coat
closet. From the foyer, however, the entry hall doglegs clockwise
around the bathroom and into the kitchen, the beehive of activity.
Off this same hallway, against the east gable end, switchback
stairs lead to a full basement and to the second floor. The stair
design offers minimal intrusion at all three levels of the house.

The second floor houses two bedrooms and a full bathroom. Grandchildren
or other guests sleeping upstairs could enter and leave the house
with little interruption of the main living area or turn a hard
left into the kitchen to nab some of Viola's hot cookies as they
came out of the oven. Grandchildren could also easily march down
to a wood-storage area beneath the porch to restock the wood bins
in the kitchen and the living room.
But there was more to the design process than
arranging rooms around a masonry core. For example, facing the
road to the north, Michael and I called for traditionally sized
windows and a custom raised-panel front door. But toward the spectacular
mountains to the south, out of the public eye, we called for large
contemporary sliding windows to capture the view and to encourage
maximum passive heating and cooling.
The kitchen is in the southeast corner of
the house, where it basks in the warmth of the rising sun. As
the winter sun tracks across the southern sky, it strikes the
10-1/2 ft. long masonry core, which stores heat and radiates it
gradually into the living spaces.
Viola wanted the bedroom to be relatively
cool, so we placed it in the northwest corner of the house to
shade it from direct sunlight. Two modest windows capture the
cool summer evening breezes.
Clean, two-step combustion is the key to the
effciency and flexibility of Finnish masonry heaters. Primary
combustion occurs in the firebox, the same as in conventional
masonry fireplaces. But instead of exiting straight up the chimney,
heated gases from the firebox enter a secondary combustion chamber,
where they burn at temperatures reaching 1,800° F or more.
The gases that emerge from this secondary chamber (mostly carbon
dioxide, water vapor and air) are so clean that they can be routed
in any direction through heat-exchange channels en route to the
chimney, with little danger of soot or creosote buildup. The heat-exchange
channels dump heat into the masonry mass, which in turn radiates
it gradually into adjacent rooms. This contraflow design
not only allows a great deal of design flexibility, but it also
offers 80% or higher combustion efficiency. Two small firings,
one in the morning and one in the evening, deliver a day’s worth
of heat.
I designed Viola's intricate masonry heater
for comfort and convenience, but I counted on her intelligence
and commitment to make the system work. Supported by a concrete-block
foundation, the masonry mass consists of a heater in the living
room, an oven and stove-top in the kitchen and a heated black-serpentine
bench in between.

I wanted Viola's heater to allow fire-viewing during the summer
without heating the masonry mass, so I installed a bypass damper.
When opened, this damper routes gases from the secondary combustion
chamber directly into a primary chimney flue, bypassing the heat-exchange
channels. Opening this damper also encourages smoke-free start-ups
year round. Once the draft is established, the bypass damper is
closed, pushing the heater into a downdraft mode. On Viola's unit,
heated gases then travel down heat-exchange channels on either
side of the heater before rising up a third rear channel that
feeds into the chimney flue. But that's not the only option. Once
this flow is established, a bench damper and a second chimney-flue
damper can be opened and the primary flue closed, drawing the
heated gases through heat-exchange channels beneath the bench,
then out the secondary flue. A turn of still another damper routes
the exhaust through a pair of vertical heat-exchange channels
behind the bench before it enters the secondary flue.
On the kitchen end, the stove-top firebox
and the oven can be fired independently with quick access to the
secondary chimney flue. Or dampers can be manipulated to send
the combustion gases around the cookstove, then either under the
bench, up and out or under the bench or up and down through the
vertical heat-exchange channels and out.
Neither of the two kitchen fireboxes has a
secondary combustion chamber because the fireboxes are small enough
to achieve efficient combustion on their own. For added energy
efficiency, the cookstove is equipped with a stainless steel hot-water
jacket that thermosyphons domestic hot water to an 80 gallon tank
in the upstairs bathroom. Just in case the masonry heater wasn’t
enough, Michael mounted an externally vented kerosene heater in
the basement. This backup heater has proved unnecessary as long
as the masonry heater is fired daily.
The complete masonry-heater system has seven
dampers, and Michael was worried that Viola might not be able
to master them all. A month or so after she moved in, he wanted
to review with Viola how to use the system and which dampers to
open first. But she told him to back off because she had already
mastered the dampers and created her own efficient and tidy firing
ritual.
Money alone did not design or build Viola’s
home and heater. The family brought to the project incredible
diligence, love and attention to detail.
Hemlock, spruce and pine logs for the timber
frame were cut from the Rothschilds' wood lot by local woodsman
Troy Romanoski. After a local sawmill sawed the timbers, they
were planed, cut and assembled on site by family members Michael,
Harry and Wendy Fleming with help from builder Chris Brown. Juliana
Rothschild, Michael’s daughter, reproduced an exquisite Chinese
painting of household gods on the heater foundation.
It took me three weeks to build the first-floor
masonry complex. I built the living-room heater as part of a 10
day hands-on workshop, then finished the rest with Aaron Moore,
a high school helper. Brown then built the chimney up through
the second floor and the roof. The chimney emerges from the roof
at the exact center of the ridge and measures 36 in. by 28 in.,
virtually mirroring the proportions of the house.

In the meantime, Michael, Wendy and Juliana laid black-slate floor
tiles at the front entry and in the sunroom. In the kitchen, native
white-pine plank flooring was installed for its warm honey tone.
Maple strip flooring was installed in the hallway, the dining
area and the living area. To emphasize boundaries, astrip of black
cherry was inlaid between the hall and the kitchen, as well as
between the kitchen and dining room. Around the heater complex,
we laid pieces of slate cut by Michael and friend David Randall
from antique sinks and a water trough that I had collected. The
slate also was trimmed in cherry.
At the bathroom threshold, the cherry strip
appears again, introducing 1-ft. square tiles of white Carrerea
marble, reminiscent of Viola's Italian roots. The bathroom vanity
and towel closets (made by local cabinetmaker Tenney Gavaza) are
of black cherry, and the vanity top is white marble to match the
floor.
With the house completed, the family set about
furnishing and decorating it. Jeff Audet, a cabinetmaker from
Lewiston, Maine, was at work on a final surprise piece of furniture
for the house, a set of cherry book shelves, when Viola died while
on vacation in California. Viola made a final, silent visit to
her home in a handmade redwood coffin, which was set above the
slate-covered floor of the porch and surrounded by flowers, family
and friends, including the logger, the cabinet maker, the tile
setter, the plumber and the mason.
Shortly after Viola died, a great granddaughter,
Viola Lou Lan was born to Harry Rothschild and his wife, Liu Cheng
Mei. Viola and her parents moved into the house.
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