Insulation workshop
Minami-Boso, Chiba, Japanorganizer
NPO Minami-BosoRepublic
lecturers
Nao KONO

Tsumiki Design

Akira UCHIYAMA

NPO Minami-Boso Republic

Masayoshi TAKEUCHI
Mikangumi
Masayoshi Takeuchi

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If an old Japanese farmhouse should ever fall into yourhands, such as this 130-year-old kominka in MinamiBoso, you’ll eventually discover that the ceiling hides
the incredible wooden structure of the roof beams. If
you happen to acquire the house in the summer, you’ll
be possessed with the urge to remove the ceiling, toexpose the beautiful wood and thatchwork above.
Tsumiki understands this urge, but cautions you that
if you follow it, you will be in for some misery once
winter comes.

Tsumiki facilitated a renovation workshop to add athermal “lid” to this ceilingless kominka, preventing
heat from escaping into the rafters and out throughthe thatch roof. Tsumiki has developed a clever DIY
system of adding ceiling insulation to old buildings
where the woodwork is rarely plumb, level or square.
Workshop participants cut slabs of rigid foam
insulation into custom panels that fit snugly into
the ceiling grid. The panels are then painted white,and the resulting texture is similar to fine stucco or
drywall. In the summer, the panels can be removed
and stored to expose the rafters again and create acooler environment.

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The beauty of the Japanese sliding door lies
in its delicate construction. Unfortunately,
they do little to contain the heat of ahouse in the winter, and their slender
design offers few opportunities to increase
thermal resistance. Another Tsumiki
innovation targets the weakest thermal
aspect of the door - the translucent paper
paneling. Workshop participants inserted
a layer of polycarbonate in between two
paper sheets, dramatically improving thedoor as a thermal barrier while retaining
the original aesthetics.

Nobuyuki Toyoguchi

24Tsumiki also created a set of moveable floor panels that can be employed during thecolder months - a slab of thick foam insulation fitted with a wooden top, making thefloor a much more inviting place to sit, dine and sleep when the cold comes calling.

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With door and ceilings modified, the next frontier was the floor.
Traditional Japanese houses often have a suspended floor that,during the summer, allows cool air to flow up into the housethrough the gaps in the floorboards. In the winter, this air flow isunwelcome. Tsumiki takes advantage of the fact that there is usually
a 5mm difference between the top surface of the tatami mats, andthe wooden trim boundary of the floor. This allows them to sneakin a Tyvek sheet and 4mm of styrofoam insulation underneath thetatami mats. The miraculous difference this makes was celebrated in
the following haiku, written by a workshop participant.

スたタイっ別ロ
た世 4 を界 mm“Styro.
Only 4mm;different world”.

From the book “Insulation Haiku Collection”
by Hiroshi Maruhashi

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Nao Kono

Momoko Kono

Natsume Naoko

Co-founderCo-founder

Art Director

Nao received his undergraduate and graduate
degrees in architecture from Kyoto University,
taking time off from his studies to work in
Switzerland and apprentice with traditional
carpenters in Kyoto. He co-founded Tsumiki
Design & Construction with Momoko Kono
when he was 27.

Momoko holds an undergraduate andmaster’s degree in architecture from Kyoto
University. Her undergraduate thesis
received first prize in the Diploma JapanChampionship, a nationwide architecture
thesis competition juried by architect
Yamamoto Riken. Momoko’s work won 1stprize in the 2009 SD Review, a Japanesearchitecture competition juried by Toyo
Ito.

Natsume holds both an undergraduate
and a master’s degree in architecture fromKyoto University, where she graduatedalongside her classmates Nao andMomoko. As an undergraduate, she won
the diploma prize for her thesis “Kami NoMukougawa” (Possibilities of Paper), thehighest honor given for outstanding thesiswork.

Nao believes that the process of improving,renewing, and renovating the built environment
can also bring people closer to each other,
forging new relationships within and acrosscommunities.
In addition to providing participatory designand construction services to Tsumiki clients,
Nao teaches hands-on architecture workshops
throughout Japan, focusing on DIY renovation,
thermal analysis of traditional Japanese houses,and grassroots creative placemaking.

At Tsumiki, Momoko facilitates a design
process that includes a legitimate creative
partnership with the client, throughcollaborative sketching and model-making
exercises.

In 2012, she founded Natsume Sewing
Atelier, through which she designs andproduces her own line of clothing,curtains, textiles, carpet patterns, andhome furnishings.
Natsume’s playful illustration style helps
Tsumiki interpret specialized architectural
knowledge, making it available to the nonarchitect.

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Koji Oshida

Takuto Tanaka

Minami Kanai

Partner & Head Carpenter
Director, Nagomi Architecture

Designer & Carpenter

Designer

Born in Niigata, Takuto studied architecturaldesign at the Kanazawa Institute of Technology.
During his time as a student, he joined anorganization called Kashimo Mokushojuku.
For 25 years, this club, has been working withresidents of Kashimo (famous for its ancientforestry practices) to design wooden architecture
for their city. This artisanal carpentry
training program culminates in a 2-weekbuilding workshop during the summer. After
participating in this program for three years,
Takuto was voted by his fellow students to serveas the head carpenter for his fourth year. AtTsumiki, he provides a range of services, fromfine carpentry to digital design.

Minami holds a degree in Industrial, Interiorand Craft Design from Musashino Art
University, Tokyo. At Tsumiki, she lends herskills to construction drawings, graphic design,
typography, web design, and logo design. She
has helped Tsumiki to include web design
services as part of their renovation package
for small businesses. Minami also performs
carpentry, painting and renovation work. When
she’s not at Tsumiki, you can find her singing
and playing guitar at various clubs aroundTokyo.

Koji was born in Kawagoe in 1974, and began
apprenticing as a carpenter with his father
when he was 18 years old. He took a breakfrom his apprenticeship at 21 to take a job
providing care for people with disabilities. Aftera transformative bicycle tour from Hokkaido
to Kyushu, Koji decided to return to his callingas an artisan, and resumed his training. He has
been working as a carpenter for over 25 years.

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About the author
Bryan Ortega-Welch is a lifelong educator dedicated to creating placesof honor curiosity and serve as engines of social change. His work
explores the transformative potential of spaces that exist in between
formal and informal learning, institution and community, work andplay. Bryan has co-founded K-12 summer programs, schools andlearning centers in the U.S. and internationally.

Bryan holds a Bachelor of Arts in Education from the Universityof California, Berkeley, and is currently a Master of Architecture
candidate at the Harvard Graduate School of Design.

Published by Tsumiki Design & Construction (Tsumiki Sekkei Sekousha), March 2019.
For more information, please contact Nao Kono at info@tsumiki.main.jp

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