Nordic Rhythms – Tipi Arkitektur's Årtidshus

Nina Haarsaker set out on a journey of discovery, when she and her architect partner, Sevrin Gjerde, decided to go their own way, designing and building their home, Årtidshus. Along the way Årtidshus involved experimenting on solutions growing from place with double glass façade passive heating, Wabi-sabi inspired clay rendered wall surfaces and the Japanese Yakimatsubayashi wood charring technique.

Tactility

Norwegian residential architecture is out of balance. The urban has become suburban. The cities are divided into zones. We have created large areas or hectares of residential sleeping zones and hectares of work zones. Driving the car between, buying your groceries on the way home. We are living in small cabin-wagons stacked on top of each other. The inside is like painted plastic, do not touch, your furniture smells of the inside of a new car. Giving you associations of luxury; in other words, what it is not. Your home has the sprayed finish and smell of the new car cabin, but this car can`t move. You have to stay, looking outside up close and impersonal at the very large neighbour wall, all the neighbors in the similar situation. You pass my bedroom window, curtains always drawn, never opened, on your way to your own small cage. In case I look out the window, and you are there, only 30 cm apart, too close. Avoid it.

What is avoided too: A big family meeting several other families, the big fire, the dance, the happiness and sorrows of life, the gypsy dream of life experienced together, it isn’t easily found happening here. Like the rest of Europe, Norway has at least 35 years of effective housing. It attains the developer goal of earning money, but quality is not needed. Rather cheap luxury finish is the main focus. The modern Norwegian dwelling consisting of plasterboards on the inside, and very often the presumed easy going painted wood or composites facades. Both inside and outside, the term “durable materials and finishes” turns out to mean composite materials that need to be changed after, maximum 15 years.

Or the case is, you are not a part of this discussion, you are privileged. You have the everyday luxury of directly experiencing qualities that in Norway for some decades has represented the bothersome, the nostalgic, the poor, the boring, the too much pine wood, the being too dark. Architects often manage this balance in their own homes, but the reality in the big housing projects they create, is plasterboard. Everything is painted white. Using simple and natural materials like stone and wood implies a lot of work, both finding resources and for creating.

In other words: As an architect, building for yourself, gives you the chance to investigate full scale and take risks, that you might not want force on a paying client. The small scale property developer, buying a site, drawing and building the house him/herself, is unusual, but can still done as a method of testing form and materials. Being the client yourself, you can finally realise professional research at the edge. This is of course usually at high economic risk, dependent on loans, material cost and, not least, the workmanship of trustworthy craftsmen. You put yourself in this kind of risk, to get the chance to do some effective and good research of architectural form and surface. And luckily, this is usually appreciated by most. You might even sell this new potential (read: a house built in direct contact with the surroundings) for a good price.

Neighbours

Building our own house we have used this chance to experiment and research, trying out several architectural concepts on different levels. This new family home is built between the remaining parts of an old farm and a large housing cooperative dwelling area on the edge of Trondheim. The site is on the edge with a thick clay plateau, facing two existing ash trees making a new farmyard with the old still existing farmhouses. The main form of the new typology of the house reflects the typology of the old main house, but extends down to include a rental unit on the lower ground floor.

Ground floor and first floor are divided by a thermal concrete block wall, covered in clay render, using clay from the site. The rooms on the north side of this heavy wall, is actively heated from water-borne floors and a fireplace. While on the south side facing the new yard, a large hothouse wall is covering and protecting the clay rendering from rain.

The house applies a hybrid system for ventilation and heating, using both new effective air-to-air mechanics and sun-heated solar panels, and old and well used ideas of heating and energy saving. The three solar panels for heating water do the heavy work increasing the first 10 degrees, from 13 Celsius degrees for intake water to the buffer tank. Natural convection driven ventilation distributes together with a mechanical air-to-air pump on low speed the heat from the inside air, and helps to preheat outside air taken in from the top. The house is in other words able to work both with, and without mechanical support.

The concept of the divided house is challenging the pre-accepted energy solutions. In the current building acts and regulations for Norway today (TEK 10), the main focus for making sustainable building is based on pre-accepted mechanical solutions. In this dwelling project we wanted instead to learn more about alternative, passive solutions, discussing good architectonic form and different zones of temperature, answering our common energy and sustainability challenges. The local Trondheim municipality has no objections towards alternative options as long as it is given a good and thoroughly studied alternative for the pre-accepted solutions. This means a lot of time for investigating, and it means more time spent on drawings and engineer-calculation. Challenging the pre-accepted means plenty of work.

How do you make the case for a concept of a divided house with two different temperature zones? You have to show a calculation of thermal loss (insulation values) during cold periods, and more importantly how to deal with heat on sunny days with one façade with 70% glass. The rule for pre-accepted solutions is maximum 20% windows of total façade. How do you get 80% windows accepted, on one side of the house? Imagine if you build a small cottage of heavy, heat containing materials. Around this house you put a conventional greenhouse or hothouse, comprising 99% window. This is the concept, adjusted so that just one façade and one roof- facing south east- covers the house. The wall behind this window-screen has a lower insulation value but a high thermal mass, and slowly evens the temperature during the day.

The wall

The house makes you aware of the only constant for you and me. Read this slowly. It very calmly urges change.

The house is a range of different views. The house is a wall. The very simple idea is the dividing wall. This wall is open, in dialogue, between inside and outside, if you are standing right there between heavy and heavy: on the one hand the dense, closed, private, resting, sleeping, dreaming, giving you the gift of making ready for the world again. On the other hand the heavy transparent stone, the glass.

Passing by, the uncle, the neighborhood children, those renting; they are looking through the big opening in the wall, looking through the kitchen room- seeing us, seeing, the fjord, seeing through the house, three layers of glass. We are in contact, smiling, waving, or actively avoiding, aware of each other.

The vertical communication, the stairs, is in this in between zone facing the new yard. The use of this room depends on the temperature outside. The calculations of the house said that in wintertime (min 25 Celsius below) temperatures are never less than 4 degrees in the buffer zone. These last two winters we have had down to min 20, but in our staircase/garden zone has never dipped below 12 Celsius degrees.

The most challenging element is the sun. The very tall ash trees have been helping a lot in the summertime, with the calculations so far accurate. Already in March we are up to 25 degrees after some hours with sun, but when the leaves arrive in June, the effect is noticeable both in the buffer-zone and for the effect from the three solar panels.

The hearth is back! Norwegian houses have missed the hearth since the 1980. Like all new housing, this house is very well insulated. But because of our ‘temperature zone’ the fire place doesn’t overheat the living-room. You only open the door to this buffer-staircase-room. The warm air enters, gives some of the heat-energy to the surface of the slow clay wall, before flowing into the hybrid ventilation system.

 

Rhythm

What are the criteria for good form? This building is surrounded by several different typologies. The main house of the old farm, a 200 year old log structure, and the big sister of this house, has a width depending on the 6 metre length of an even tree trunk. This gives a lot of light flowing through the house, but is also more challenging, solving the narrow plan. The proportions of this elegant, old house has been the premise for the new one, sensitive to not fighting but remaining a part of the close family with the long horizontal and narrow form.

The house is reacting directly to the plot situation. You can read it in the dimensions and rhythms of the façade. The wooden cladding on these two houses has the same dimensions. The colors are contrary but still natural, the old lead-white contrasts with the new charred and coal black. The structure of the old house has the rhythm of axis every second metre and each 120 cm where windows were positioned, while the new house continues the narrowness and verticality inside with axis of 110cm. To the north the long, horizontal window is divided in the same rhythm, but is more closely related to the window ‘ribbons’ of our surrounding housing cooperative neighbors to the west and north and the east. The asymmetrical placement of the ridge is given functionally, by placing the massive dividing wall inside, giving the living rooms larger and the size of the external sun-panels and the temperature dependent zone towards the south.

The rooms, the use of the house, and the different temperature in the different rooms all tell your bodies secrets. You adjust. You rest. You want to rest on the floor. Rock the hammock. You want to jump. You change something, to get comfortable. The different ways of living, different number of dwellers, guests, situations…

Giving the surface behind the glass a heavy clay render in a light colour slows the time; the material takes very slowly heat up from the sunlight, and equally slowly warming the room in the evening.

In this zone of change; you are experiencing the seasons. The roof windows, stars shining on you as you make your way to bed. Listening to the rain, listen, you don’t have to open the window, your house is in the world, only making each sound softer. Making this building different from pre-accepted new housing, where all the layers of insulation and the noise from the mechanical air system eliminate the sounds of the world. Imagine the different sounds. The sharp sounds, the forces. The soft sounds, snow slowly landing, giving the glass roof a denser, darker, still lighter, a new color, and a more intimate contrast. The spring is coming, the wind waving the branches, the sun giving the clay-rendered naked wall beautiful rhythmical shadows. 

The Big Fire

The charred wood facade has become a slow time companion. Like the houses; they stay for a long time. Outlive us.  Outlive our neighbours. But the panel cladding on these surviving neighbour forms have to be changed every so often. Repainted, and when rotten, replaced with new panels, new paint, repeated, continuing slow rhythm in an eight to ten year cycle.

The coal black surface, the 2-3 mm thin layer of charred wood, has another rhythm. This is slower. The Japanese have experienced this. And the Finnish people as well. They use history, they are learning from experience (Wiki; Greek translation of the word history: learning from experience). Doing this requires a place where it is possible to make and light an open fire, with access to water. This means definitely outside the city areas, easily done in Norway. The process for a house of this size takes one week, in other words approximately the same time you would use for painting/ staining the same building. At fifty metres distance the visual impression is the same as for that of a dark/ black stained surface. The important difference is that you do not have to repeat the operation for at least 80 years.

The charred wood surface has become increasingly popular as façade treatment in the north as an addition to the trend of the wood weathering untreated pine-boards. The main reason for this interest is the already mentioned maintenance aspect; you use no more time burning than painting, and you do not have to repeat the process or change the façade for a lifetime or two. It has environmentally friendly advantages concerning weather resistance, also compared to the ecofriendly non-treated surfaces. It is particularly interesting for humid and warmer climate, as it is in a high degree rot and bug resistant, in addition to its fire-resistance - the main reason why the Japanese used this technique in small and dense ancient villages.

In Norway charring wood with a fire has only been commonly known technique when making a fence with wooden stakes put directly into the earth, burning the surface of the part covered with soil. What first inspired us was a project by Finnish architects visiting NTNU in the 1990, using this technique. (And their joke about “you should not do like our Finnish friend, who used the flame-throwing projector when vodka-drunk, his whole cottage burned down”!). A colleague came with nice excursion pictures of Yakisugi panels used in modern housing in Tokyo 2011, and not at least NTNU students experimenting with small 60 cm chimneys, as a process technique seen in work of Japanese Terunobu Fujimori. But the main inspiration has been following with interest the two charred walls of a traditional food store log-house in the mountain village Teveldalen, which was exposed by firing in the 1980s, the surface did not lose any color and had an even an nice black surface looking perfectly black stained from distance until it was taken down around 2000.

Only two producers in Norway have decided on going commercial on charred wood-surface; one in the South East of Norway with hardwood, and one a local in South Trøndelag/ central Norway, using spruce. The reason we decided to do the charred wood surface treatment ourselves, was first of all our access to close by mountain pine forest. The logs were dried there, and we used a local saw-mill cutting the panels for us, according to our plan for the building to connect with the old farmhouse panel-dimensions.

Teveldalen also was the perfect location for our charred wood panel-production experiment; to make a small fire and having access to electricity for cutting panels, and water to shower the panels and stop the fire. This gave us the possibility to test both a grill-idea, like the professional producers do with gas, and the chimney effect-method, which I found by chance on YouTube from Japanese television in 2011.

This chimney-effect method involving using three panels to make a chimney, Yakisugi (or Yakimatsubayashi to be more correct, since we were using slowly growing mountain pine-wood, and not hardwood), was the most effective. You only need a small fire with fine cut sticks, and enough air in the bottom of the fireplace for a good firing. The chimney effect burns forcefully more or less to the middle of the pipe, and after a couple of minutes you turn the pipe upside down, to get an even and covering and total charred surface. The pine wood panels were quite thick (25mm), and we had to use gas to burn the sides of the panels. This was only necessary because of our detailing, and our wish to have a totally black and even façade. The whole process is easily done, and fun. Our big family with relatives in all ages was involved over a summer week, but to make an effective line you have to be at least two, preferably four. As a tutor at NTNU Architect and Design faculty there have been opportunities to inspire students, and we have been involved in the process with advices for three different NTNU Live Studios including the Rindal Star cube.

What will the neighbors say? Having hundreds of close by neighbors and friends of the children visiting, we were expecting critical comments of the rough surface treatment. This has not happened. Most offer positive comments, with some saying only: “I`ve seen this before, “extreme makeover”, on TV. Mainly on furniture. Interesting you did it on a house”

Surprise

Trondheim and Norway is, like England, full of clay. All through Europe there is growing interest for this simple and cooperative material through Europe, in Germany, Austria, Greece, and Turkey Even so using local clay as rendering or rammed earth is uncommon in Norwegian and rare in Scandinavia. In Norway the brick making industry has ended, and has been sold off. The last factory, Bratsberg Tegl closed in 2014. The cement-industry rules the market. Clay is more or less forgotten local building material.

Though recent research has discovered that our local blue-clay can actually replace 25% of the cement in concrete, clay is mostly seen as a problem. The main problem are the dangerous layers of quick-clay, sitting several meters under the surface, a threat to building in Trondheim and many other Norwegian cities. In Trondheim it is the geologist’s calculation, which is the most important one in the majority of new building sites; is it possible to build? How much weight of clay will have to be removed from the site to be able to build? At least one sixth of the building budget of all densification projects preparing to build on clay sites, us used up on preparing the site ready for actual building  

The old and nearly forgotten rendering technique may seem sentimental, or even trendy in a niche-way. In retrospect, two years on, the interesting thing about this experiment for us was, first of all, how much resistance there was in ourselves for doing something different. Is there any experience out there at all, to learn from? And where to find it? Where to find all you need for the clay-mix? How to make a clay render? What tools do we need? Will it work? What will it look like?

When you figure it out, it is surprisingly easy to do it. And at the same time surprisingly heavy work. You have to use your whole body, not to hurt your precious computer arms. It’s also surprisingly fun. And that it in the end becomes surprisingly beautiful in a Wabi-Sabi way, showing the roughness and natural simplicity of life. Both sides of the great wall show traces of one doing their part of clay render. No family portrait is hanging on the walls of this house. In place you can see the temperament and touch the movements of the hands of our beloved: the slow motions of my uncle, the effective and expressive parts done by my father, some bored and fast movements from my husband Sevrin, and the starting out soft but becoming increasingly neutral large and professional parts done by me. The traces become part of the surface. Perfect, like the human skin.

Nina Haarsaker teaches in the architecture department at NTNU. Nina maintains a blog about the project which includes considerable technical information. She can be contacted here nina.haarsaker@ntnu.no

OutSIDE InSIDE InBETWEEN – Artidshus
Technical Information

Pictures and information on doing charred wood, clay render and about the simple hybrid energy concept of the two temperature zones are available at the blog: www.aarstidshus.blogspot.no
The building: Årstidshus Blaklia
Address: Blaklivegen 18/20, Trondheim
Completion: 2014
Energy performance kWhm2:
Calculated energy use was 106 kWH/m2. Actual annual use first year was 88 kWh/m2.
Area use 1:  The building is divided in two:

Family part (2 floors) total area 186m2 BRA, Winter area is 110m2, 
28- 40 m2 depending on season per person /family of 4

Flat for rent ( one floor) total 57 m2, for couple: 28,5 m2 per person
(This is more than 10 m2 under Norwegian average pr 2002 is 52 m2/ 2016: ca 60m2, https://www.ssb.no/a/samfunnsspeilet/utg/200404/10/tab-2004-09-15-01.html)

Area use 2:  The building is designed to have the flexibility from being one big three floor family home or easily divided horizontally into three flats, and even becoming commercial/ an office. First floor has universal access.
Material use: Focus on use of durable and easily recycled materials.
Construction In situ concrete foundation, (with the long time future possibility of becoming a beautiful ruin)
LECA
Framework: wood from Støren, local spruce
Insulation: reuse of cellulose, hemp in main rooms,
Sparely use of toxic substances on some of the bathroom walls, and plastic between fundament and the ground.

Surfaces
Walls outside:
-two floors with local mountain pine wood yakisugi-treated surface,
-groundfloor three walls with composite concrete panels
-three-layered glass

Walls and roof inside:
-CLAY rendering from site,
-Birch and plywood both as vapour-barrier and inside surface and handmade shelves
-Reused doors from local office, found cheap on net

Floors: pine, oak, concrete, clinker-tiles

Energy source
Hybrid; The sun, both from the three solar panels and the hothouse/ winter-garden, air to air system on low pressure difference, electricity and clean-burning fireplace using dried wood from nearby forest.