A few years ago I needed to explain how to do a tectonic analysis to my students in UC Berkeley. Tectonics in architecture is usually understood as the activity of construction as an art form.

At that time, The High Line was a very popular precedent that students liked a lot, and I presented some construction details through a series of fast sketches I prepared. 

Nowadays, I go for a stroll to The High Line from time to time, and I am always struck by the Park Rules: 

The following are not permitted while on the High Line:

• Walking in planting beds
• Picking flowers or plants
• Throwing objects
• Sitting on railings or climbing on any part of the High Line
• Bicycles
• Use of skateboards, skates, or recreational scooters
• Amplified sound, except by permit
• Solicitation
• Commercial activity, except by permit or otherwise authorized
• Littering
• Obstructing entrances or paths
• Drinking alcohol, except in authorized areas
• Film or photography requiring equipment or exclusive use of an area, except by
• permit
• Events or gatherings greater than 20 persons, except by permit
• Smoking
• Dogs

Although those are (kind of) common rules for parks in NYC, I think they still surprise me because I remember a line from the narrative summary from Diller and Scofidio + Renfro’s website:

“A ‘pathless’ landscape, where public can meander in unscripted ways.”

Wait… You cannot walk your dog in this “pathless landscape”? It appears from the rules there is not much you can do there—other than walk and sit in designated areas (paths) unless you get a permit, for which you need to script (write down) your intended activities.

In any case, the High Line is still a beautiful park. Highly regulated, but beautiful.

Some time ago a Japanese colleague told me that the best energy efficiency standards of Japan were not even close to the lowest standards of Germany. And yet, Japan used a quarter of the energy that Germany used in heating. 

Although I could not find the sources for any of those claims, the whole discussion seemed ill-focused, as when comparing tomatoes to potatoes: they have similar origin and sound quite close, but they are different things.

But, Japanese houses are cold, aren’t they?

Japanese houses are famously cold in winter, but life around the tatami room is a warm experience. 

Instead of heating the whole house, or the whole room, heat is focused where needed, just by the table. Cold evenings are kept at bay under the kotatsu, where kids do their homework, parents work, the family enjoys dinner, and friends have a drink.

The kotatsu is a short-legged table with a heater attached to the underside, and covered by a blanket or a quilt. You sit at the table, and your legs are covered and warm under the kotatsu. The upper body is kept warm with the help of thick clothings like hanten (a kind of padded jacket). If you are planning to move in and out from the kotatsu frequently, a tanzen would be a better choice for clothing (it similar to the hanten but longer, covering the legs as well).

Thus, thermal comfort is achieved with a small heat source and proper clothing, which actually makes a lot of sense from an energy efficiency point of view. In Norway they say “There is no bad weather, there is bad clothes!” Is it really necessary (or even wise) to crank up the thermostat just to walk around in T-shirt?  

OK, the tatami room gets nice and cozy with the kotatsu, but why are the houses so cold anyway?

We can find the reasons behind all this coldness in the way houses are built:

The first reason is, of course, earthquakes. Due to the constant seismic activity in the islands, the Japanese developed a light construction system with wooden structures, thatched roofs, tatami floors, and shoji partitions (paper over a wooden lattice).

Light structures are more resilient (less stress on the members), and shake and move with the earthquakes without snapping. (As an added benefit, if they do snap and fall over you, it is easier to crawl away from under light rubble.)

Then, humidity: Summers in Japan are hot and very humid, and structural wood, thatched roofs, tatami floors, and paper walls tend to rot very fast if they stay wet. Thus, the best way to prevent degradation is by allowing them to dry, which is achieved by good ventilation. This is, houses needed to be drafty.

Constant seismic activity also produces material fatigue on the structural members: minor cracks that appear at every cycle of movement. And after a while, the whole structure collapses. Unfortunately, repairs do not work well and there is no economic way to avoid material fatigue. For that reason, houses in Japan have had a pretty short lifespan (20 to 30 years), although constant advances in construction technology are pushing those numbers up nowadays.

The short lifespan brings another issue that impacts on energy efficiency: Upfront investment in insulation and double pane windows will not be paid off in lower utility bills during the life of the building. 

Why is central heating so uncommon in Japan?

An efficient central heating system requires a properly sealed and insulated exterior envelope. And as explained above, that is not usual because it is expensive considering the whole life cycle of the building.

You may find air conditioners on several rooms of the house, but they will not be switched on all at the same time. Similar to the way Japanese use the kotatsu, they switch the air conditioner on only when they are using the room.

In sum, the tatami room is a nice example of flexibility and energy efficiency. Strategies for energy efficiency shouldn’t consider constructions as isolated systems, but as part of larger rhizomes that encompass not only climate and geography, but also habits and costumes, including furniture and clothing.

The Ultimate Flexible Space

While in Japan, I lived in an apartment with a tatami room. Since then, I have been a staunch advocate of the tatami room as the best possible room one can have at home. 

I always tell my clients that they need a tatami room. And I have succeeded… Never.

Well, almost never. I convinced my wife that we should build one for ourselves, but she lived with me in that apartment for 4 years. So, she understands.

What is a tatami room and why should I care?

A tatami room is a traditional Japanese-style room, and they get their name from the flooring material: tatami mats. These mats are roughly 6 feet by 3 feet (1.8 m x 0.9 m) and they are neatly arranged following patterns that vary, depending on the type of room, use, and occasion.  

The tatami mats are covered by woven soft rush (Juncus effusus) and have a distinctive feeling under the bare feet (no shoes allowed in these rooms, of course. Socks are optional). They feel fresher than carpets, and softer than wooden floors. However, they are firmer than mattresses. 

And they are fun: when western kids encounter a tatami room for the first time, they usually feel like doing some pirouettes on it, as the flooring material kind of invites you to put your hands down, touch it and roll over it.

They also have a particular smell, specially when new. If you ever lived under a thatched roof you will find it familiar: earthy, smoky, woody… Floral perhaps. Very pleasant, but difficult to describe.

Tatami rooms are part of contemporary life in Japan, and state-of-the-art houses and apartments usually include one of these rooms, as they are the heart of the house.

Can I put a sofa in a tatami room?

Yes, you could, but you would be defeating the purpose of the room.

The tatami room is a very flexible space and it changes functions during the day (and night). It is used as living room, dining room and bedroom, almost effortlessly transitioning from one function to the other.

When used as living and dining room, the usual arrangement is minimal: some sitting pillows or cushions, a low table, and the focus of attention of your choice: a TV set, music, or just conversation over a cup of tea or drinks.

When used as bedroom, things don’t get much complicated either: just lay the beddings (futon) and you are ready. The beddings are basically a thin mat laid on the tatami (shikifuton), and then a quilt to cover yourself (kakebuton).

The interesting thing is that the transition from living room to dining room, and then to bedroom, is extremely fast and smooth: when it is time to sleep, pillows and tables are folded and stored away, and sleeping mats, sheets and covers are brought from the closet. In the morning, mats and quilts are taken outside to dry, then folded and stored, and tables and pillows come out from the closet, getting ready for breakfast.

These closet (oshiire) is about 32” (~ 80 cm) deep. It is deeper than the traditional western ones, which are about 24” (~ 60 cm), and have less partitions. Usually, it has just one shelf at about 30” (~76 cm) high.

The key to all this flexibility is of course the type of furniture… Well, actually, it is a lifestyle, but one doesn’t need to be a zen monk to make it work.

The furniture that goes into a tatami room is small, light-weight and removable. You don’t use a California King bed. I mean, you could, but again you would be killing the idea.

I have used a California king bed and I did enjoy to extra room. But, it actually felt small when compared to sleeping on a tatami room, where the whole room is your bed.

Would I not die within one hour, sitting all the time on the floor, cross legged on a pillow, and without back support?

Yes, well, no, you won’t die, but I agree: it will not feel comfortable for long (unless you are used to it, or in fact a zen monk)

Fortunately, there are several things that will help us here. 

One that I am very fond of is a pit under the low table. It is called horigotatsu, (I made a drawing here) and you put your legs down when sitting at the table. At about 16” (~40 cm) deep, it makes sitting at the table very “normal”, if you are not used to tatami rooms. In fact, it is more common in traditional Japanese restaurants than in houses.

Once dinner is finished, the tables are folded and stored, and the pit is covered by a tatami mat. Once again, the uncluttered room gets ready for the futon. 

The dimensions of tables, pits and tatami are coordinated: some pits are 1/2 tatami, and others are 1 tatami. Longer tables and pits are of course possible, by adding to the 1 tatami module. Again, those are common in restaurants.

Another very convenient piece of furniture is the legless chair (zaisu), and when used together with the pit under the table it makes the whole experience extremely comfortable. We have now back support and room for legs, so it is almost the same as sitting at a common (western) table.

The tatami room is in fact part of an assemblage or rhizome (following Deleuze and Guattari’s theory) of space design, construction materials, energy efficiency, furniture, clothing and ceremonies. I will delve into energy efficiency, clothing and ceremonies in my next post.