Marcin Kulesza Dissertation Low Tech

7/22/2019 Marcin Kulesza Dissertation Low Tech

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LOW-TECH SYSTEMS IN MODERN ECOLOGICAL CONSTRUCTION

Marcin Kulesza

VIA UNIVERSITY COLLEGE HORSENS, DENMARK

Bachelor of Constructing Architect

November 2010


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LOW-TECH SYSTEMS IN MODERN ECOLOGICAL CONSTRUCTION

Marcin Kulesza November 2010

Study number: 143804

VIA University College, Horsens, Denmark

Bachelor of Constructing Architect

Consultant - Erik Toft

2 Copies - Font Arial 11

All rights reserved no part of this publication may be reproduced without the prior permission of the

author.


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Table of Contents

Introduction.................................................................................................1

Aims.............................................................................................................2

I. Building low-tech.....................................................................................3

1. Climate and Architecture...............................................................4

2. Low-tech in the structure.............................................................11

3. Building Process.........................................................................14

II. Materials................................................................................................15

1. Common building materials.........................................................15

2. Low-tech materials......................................................................18

- Earth..........................................................................................18

Rammed earth.....................................................................19

Mud brick.............................................................................21

Cob......................................................................................24

Other earthen materials.......................................................25

- Cordwood masonry...................................................................27

- Straw.........................................................................................29

- Living roof..................................................................................30

- Other low-tech materials...........................................................32

III. Low-tech in modern construction: cost............................................34

IV. Summary..............................................................................................36

Bibliography .............................................................................................37

Illustration index.......................................................................................38


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Introduction

Today we live in a world of technology. We live in the quick times where information is

the most important. New inventions are made to make our lives better. So it seems. But is it

really the good direction? We seem to use resources that earth gives us without thinking of

future. In architectural filed this pattern is very visible. In buildings we use modern

technologies and materials, just to build faster and higher. For producing the most popular

building materials, such as concrete or steel, we need to extract it from ground, prepare it in

factories, and then transport it to the building place. All of this is very polluting and using

many resources.

But for many years now more and more ecological solutions are introduced. The eco

stream become trendy. Ecological or sustainable architecture, as it is called, is becoming

more popular. Of course development is inevitable, but we can do it consciously. The target

of sustainable construction is to reduce resources spent for building. It can be reducing of

pollution or energy in using of buildings. The means can be also very different. From a high

technology solutions that capture sunlight and turn it into energy to simple low technology

and nature friendly material choice. In this work I would like to focus on a low- tech

construction in architecture.

Then what is a low-tech construction? Its a building method that does not use

modern inventions, technology and materials. Instead it focuses on the most simple

solutions. The choice of materials is also very natural. That method brings us to the times,

when people were forced to build the house without any special technology. They did it with

their own hands and from what they could find nearby. Nowadays, however buildings need to

fulfil many demands and provide a certain level of comfort. As we mean low-tech today is

that we construct a building from local materials and use their advantages. Sun, wind and

earth are also used in a way to provide good interior climate without high-tech solutions, such

as air conditioning. The goal is to use the knowledge that comes from old times, combine itwith today ideas and to make a house that fits its place, its good to live in and it is also

beautiful.


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. 1. ( , )

Aims

In this work I will try to answer following questions concerning ecological, low

technology, construction:

- Why should we consider building low-tech?

- What are the low technology solutions that we can use in the building?

- What are the natural building materials that we can build from?

- Is it worthy to build low-tech?

. 2. ,


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I. Building Low-tech

To build low-tech, we need a construction that do not require an advanced and

sophisticated technology to create a building. And that building will still fulfil all or most of the

demands that we expect from a house. In every aspect of modern construction, we can find a

alternative solution. Very often these solutions were already here for centuries, but

industrialised world just replaced them with modern technology. Nowadays we are used to

uniformisation. Buildings are built from similar materials, just to minimise costs and speed of

construction. Same houses can be found in Denmark, Egypt or Japan. To provide comfort, a

high technology is forced into buildings. We fight with negative conditions instead of adapting

to them. Old building techniques are claimed to be obsolete and not good for todays

requirements. But this kind of thinking might be wrong. Antic way of construction has been

developed by years, and for specific location. Old architecture found the way to deal with

temperature, rain and wind of that place, without advanced technology.

Now, if we want to build a low-tech house, we should learn from old, vernacular

architecture, combine it with todays knowledge and choose the simplest solutions for

construction in peace with the nature. Why should we use materials that were produced in a

factory 1000 km away, if we have resources right on site? Why do we need to install air

conditioning, if we can avoid overheating by proper building siting and natural ventilation?

The use of smart, alternative solutions ensures you that the building will provide good indoor

climate (without expensive technology), be made to suit exact people and place (not an

anonymous house from a catalogue) and be environment-friendly.

Low- tech construction is connected with the trend of Green Architecture. The way of

building using simplest solutions and natural materials are obviously ecological. The ways of

dealing with climate without modern devices is saving the energy. So is proper insulating and

orientation with sun and seasons. The usage of natural materials, that can be found close to

the site is also very important. By doing this you save the energy used for mining, production,

storage and transport in the production process of modern materials, such as steel orconcrete. Not to mention the pollution and water usage. Building materials, like wood, clay,

stones, or second-hand products are much less impactful for the environment. Ecological

requirement for minimal damage to the earth during construction is also very close to

principles of low-technology building. Eco-houses are using minimum foundations,

sometimes are even raised from the ground. Even in the case of buildings that are put

underground (which require a lot of soilwork during construction) the final effect compensates

the damage. Very common is also using of green roof, that is not only a living space, but a

insulation and water management system.


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1. Climate and architecture

,,If our designs for private houses are to be correct, we must at the outset note of the

countries and climates in which they are built. One style of house seems appropriate to build

in Egypt, another in Spain, a different kind in Pontus, one still different in Rome, and so on

with lands and countries of other characteristics. 1

This is what a Roman architect Vitruvius wrote 2000 years ago in his ,,Ten books on

Architecture. It is obvious and known for thousands of years that the climate is one of the

main factors in building design. The basic need for man to provide shelter is dictated by

weather. Different buildings are built in the desert and different in arctic. Through centuries

people developed the best and most optimal ways to deal with even extreme conditions. In

this chapter I will present a range of different climates and solutions that people invented for

adaptation.

. 3.


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Climate is a sum of many factors that create weather. The temperature depends form

the sun. Closer to the equator the sun is higher on the sky and gives more heat. Closer to the

poles, suns energy is spread on bigger area, so the heat is lower. Time of sunshine and

angle of rays depend also on the seasons. Water is another important factor. In some parts

of the world water is precious, there is hardly any rain, thus air is also very dry. In other parts

one has to fight with too much water and is in danger of flood. Attitude towards wind also

depends from location. In the desert air brings coolness, so buildings are adapted to catch it.

In cold north, wind is a problematic factor that need to be avoided. Habitants of moderate

climates have to deal with seasons, in which both overheating and cold are present.

In all those climatic zones people were forced to develop different strategies. Using

sun, water management and ventilation is dependent form the site. Lets have a overview of

certain climates: hot (dry and humid), moderate (dry and humid) and cold (dry and humid).

Hot and dry

Extreme hot summer and mild winter, lack of rain, very fierce sunlight. Big differences

between day and night. The main problem is heat. To deal with it, permanent residents use

buildings with big thermal mass, to delay the heat. Stone and mud bricks are used. A lot of

shading and ventilation that captures wind and bring it to the inside. Water and plants serve

as a cooling system, because of water properties of decreasing temperature by evaporation.

. 4.


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Good example of building adapted to such climate is a town house in Cairo. To

combat with sun, there is a lot of shading, the openings are limited and covered to block

direct light. Walls are made of heavy stone, that gets warm very long, and gives the heat

during cold night. Important part is inner courtyard, that is open to the sky and shaded. For

ventilation the wind towers are erected. They capture wind, direct it inside, where it can be

cooled by water and plants, and distributed in the building. The lantern above the courtyard

serves as a wind outlet and provides indirect lighting.

. 5.

Hot and humid

High humidity, high temperatures. Short or no winter, little differences between days

and nights. Lots of rains and not so severe sun, because of the clouds. Houses in this

climate are open, light structures. Big openings provide ventilation throughout the building,

and large overhangs prevent the rain and sun from going inside. Houses are elevated above

the ground to protect from flooding and to get additional ventilation through the floor.


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. 6.

Traditional Japanese house is a good example of adaptation to subtropical climate. It

is raised above the ground to avoid moist and for floor ventilation. Structure is a skeleton with

big, flexible openings. Sloped roof with large overhangs redirect the water and limit the sun

access. The plan consists inner and outer veranda, that can be used differently throughout

the day and the year. Walls are made of panels, which are movable to adjust the amount of

light and wind according to the need. Openness and flexibility is a key to adaptation in

Japanese climate.

. 7.


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Moderate and dry

Long, warm and sunny summers and cold winters. Lots of wind. Big differences of

temperature daily and yearly. Buildings have to be either solid and insulated. Transition

areas are common. There is also shading that blocks summer sun and allows winters light to

penetrate the house. Central heated rooms distribute heat to other rooms in winter.

. 8. ,

Turkish country house has a good solutions for a moderate dry climate. The walls are

both heavy and well insulated to provide good thermal mass and to keep the house warmduring winters. Low pitch roofs with overhangs protect from hot sun. Living areas are used

differently during hot and cold seasons, not heated areas serve as a buffer both in summer

and winter time.

. 9.


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Moderate and humid

Humid, rainy, changeable areas next to the coast lines. Short, warm summers and

mild winters. Windy. Buildings have to be protected against cold winds and humidity. Often

the gable faces the sea, from which the wind blows. In some places, to protect from the wind

and to provide a buffer zone, a double, glass facade is used. Walls are heavy and well

insulated. The central chimney is a main part of the house during winter.

. 10. ,

Example of a house adapted to such climate can be a common Danish house. With

gable towards wind direction, and walls made of bricks. High-pitch roof protects from rain and

humidity. The porch as a transition zone is used to limit heat loss due to wind and cold.

Cold and dry

Extreme cold and severe winds. Long winters and short summers. Polar night and

day phenomenon. To survive in such climate people need to combat cold and freezing

winds. The use of semi-circular shapes minimizes the area exposed to the outside and helps

to avoid the wind.


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. 11.

Eskimo igloo is a good example of construction adapted to extreme conditions. The

hut is built of snow blocks, that are porous and therefore insulating. The entrance is below

the surface level to avoid wind. With inside covered by furs and a little heat contribution, the

temperature inside is comfortable.

Cold and humid

Dark, cold winters and bright, cool summers. Humid and windy weather with short

vegetation period. Insulation of walls is very important and can be achieved by using animal

skins, massive timber logs or digging the house under the ground. Central fireplace or a

chimney is a heart of the house. Modern houses tend to expose large, insulated windows to

the south to gain a heat from the sun.

. 12.


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Swedish log house shows a couple of good solutions for cold climate. Buildings are

placed next to the forest, to shelter it from the wind. Massive logs in the walls help to insulate

and keep the inside warm. Low-pitch roof keep the snow on it, which is considered as

additional insulation. Heavy chimney inside warms the house during the day and retains the

heat during the night.

. 13.

2. Low-tech in the structure

Low-technology solutions for a house can be found not only in the aspect of climate

and indoor temperature, but also in construction field. The way that a building is dealing with

the loads, the foundations and roofing can also be very simple. It is not necessary to use

reinforced concrete structure, if we only want to build a small house. Some of the principles

of building physics were discovered long time ago and successfully used ever since. Building

durability depends either from the shape, or materials used in construction.

Some shapes are more stable than others. A very popular rectangle is a very

unstable construction and have to be strengthen by dividing into triangles. Triangle is the

basic solid shape in building mechanics. Even in the simplest wooden post and beam

construction it is common to add some diagonal elements in the corners to make all structure

stand firmly.


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. 14.

Another important shape is an arch. Since ancient times arches were used to create

amazing structures. If you want to cover a span, like roof or some opening, we could use a

beam. If we put a load on it, we can see that it needs to be dealing with pressing and pulling

forces inside. But if we want to build from stone or mud, then the arch is a solution. In this

shape all elements are only pressed.

. 15.


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A dome is another great shape in low-tech world. Its an arch, but turned in 3

dimensions. It is extremely stable and allows to build from materials which are not so strong

(also only pressing forces). Igloos or African mud huts are examples of such constructions.

. 16. ,

What about structure materials? Today we use mostly concrete, steel, wood and

bricks in load-bearing elements. But there are dozens of other materials that can bear a load

of a couple, or at least one storey and a roof of a building. Walls made of earth, clay, straw,

reed, tires, paper and even snow are possible and working. There are even buildings made

of glass bottles! Tipi or yurt is an example of a structure made of tied sticks and covered with

animal skin. Of course we would not live in nomadic tents nowadays, but it shows that it

doesnt take much to build a solid structure out of scraps.


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. 17. (, A)

3. Building Process

As we can see there is a lot of methods to build with little technology. With a gooddesign and execution, a low-tech building can be as good as a typical modern house.

Advantages of such houses are that they are sustainable. They are built to fit the place,

where they stand and the people, who would use them.

Although it is good to build ecologic houses, it can be problematic. First of all, there

are certain rules and laws about construction. Some green solutions might be seen as not

fulfilling the codes. Then, went it comes to construction of the house, there might be

problems with contractors, who would build it. Many companies are used to build in certain,

modern way, and asking them to use other methods can be problematic. Thats why it is

important to be aware of the of the whole building process and make good decisions from the

beginning. It is a good idea to make a research and hire a proper architect and building

professionals, to execute the house the way it should be. Another, maybe the most green

solution, is to gather your friends and build the house on your own.


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II. Materials

Low-tech attitude in building is present mainly in the materials used for walls, floors and

roof. Choice of a good material is very important from the beginning. We can look at the

matter from different points of view. We should take following things into consideration:

- Accessibility The material should be in close reach to the building site. It should be

local and easy to get. The point is to reduce transportation and respect the context

(it is not advisable to build from wood in the desert, or stone in the forest).

- Ecology Use of every material have some impact on environment. The energy used

to produce, the resources used in processing and pollution emission are important

factors indicating eco-friendliness. Also potential of re-using and recycling after

demolition is important.

- Cost The cost of material is one thing, another is a labour intensiveness to build

from that. Some materials we can get almost for free, but then we need to spend a lot

of time and energy in construction. Sometimes it is another way around.

- Demands We need to fulfil certain demands for U-value, static, fire, health, etc.

Rarely it is possible to use one material that is good for everything.

1. Common building materials

We tend to use the same building materials in every construction. Through the years

the industry developed a certain way of producing houses. New materials are invented, but

they are more and more advanced. We use high technology and it seems that no one looks

behind for more simple solutions.

Ecological trend in building industry has a growing influence though. There are many

alternatives for modern materials and they are successfully used in modern sustainable

houses. Not everyone is aware of an impact, that some popular materials have on theenvironment. Lets have a look at the two most used materials in construction and see if we

can find an alternative for it.

Steel it is an alloy that consist mostly of iron and up to 2% of carbon. It is used

widely in construction because of its hardness and flexibility. Steel can be used in load-

bearing members, as a sheeting or as a reinforcement in concrete. Production of steel is very

complex and energy consuming. It can be extracted all over the world, but its reserves are

limited. Iron ore is extracted usually in big, open quarries, which leave a scar in a landscape

and disturbs the groundwater level. Deep mines also have a destructive effect on ground.


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One ton of iron ore produces up to 6 tons of waste material. After excavation the ore need to

go through complex process to turn into iron. It is crushed, cleaned, sintered and smelted in

blast furnace in temperature of 1800oC. To produce one ton of iron, it takes up to 600 tons of

coal and around 3 million litres of water. Then the iron is turned into steel. It can take place

either in blast furnace, or in electric arc furnace. During production a large amounts of carbon

dioxide are emitted, as well as a sulphur dioxide, fluorine compounds, dust and another

heavy metals. Producing of stainless steel and protecting steel from corrosion by galvanizing

produces another serious pollution by organic solvents, cyanides, chrome, phosphates,

fluorides, etc. That is just for production of steel. Then it need to be formed in proper shape

and transported, which makes another impact.

. 18.

Concrete It is a mixture of a cement, aggregate and water. Concrete can be used

almost in every part of the building - from structural parts to cladding and roofing. There aremany types of concrete using different materials. The most used Portland cement and a

variety of other use lime as a main ingredient. If we just follow the process of making lime

binder from the lime ore, we would have a picture of energy consumption of it. The

production begins from calcination of lime. It takes place in plants in temperature of 800-

1000 oC (production of Portland cement requires around 1500 oC). Carbon dioxide is

inevitable product of reaction taking place in the furnace. Another portion of CO2 comes from

burning fuel. After that, depending from destination, there can be another reactions

processed, like slaking or hydrating the lime. All in all in cement production carbon dioxide


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is main pollution. Due to high temperatures needed, other substances, like nitrogen oxides

and sulphur dioxides can be emitted. Dust can be also a problem. Cement industry is quite

central, so another impact from transport is made.

The table shows a number of building materials and a basic data indicating the

energy and resources used in production and emission of greenhouse gas, CO2.

Material Embodied energy

(MJ/kg)

CO2impact

(g. CO2/kg)

Use of water

(litres/kg)

Cast Iron 13 750

Steel (from ore) 25 2200 3400

Aluminium 200 15000 29000

Copper 85 6000 15900

Concrete (with Portland cement) 1,5 180 170

Glass 12 700 680

Mineral wool 20 1700 1360

Plasterboard 5 250 240

Stone 0,5 10 10

Bricks 3 190 520

Bitumen 50 400

Polystyrene (foamed) 125 3500Timber 16,5 300 330

Plywood 25 750

Earth (compressed) 0,5 20

Straw bales 14,5 5

Table 1. Building materials impact on environment

This overview is to show that building material industry is very big and complex.

Some materials that seem to be simple and harmless, actually are great polluters and energy

consumers. The aim is to learn the basic principles of production of building materials and

choose the ones that have less environmental impact. We can also look for alternatives in

low-tech solutions.


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2. Low-tech materials

Earth

Earth is a great source of building material. It is estimated that nearly one third of

population of Earth lives in a houses built from earth. And it is not bricks, stone or cement,

that come from the ground, but the soil, the mixture of clay, sand, silt etc. Earthen buildings

are not only homes, but serve also for work, worship, agriculture or defence. Because of its

availability, structures from soil can be found in every place on the planet, from deserts to

arctic. Earth buildings may be perceived as construction for poor, but it is not true. One can

find a structures like airports, hospitals and museums also in highly developed countries.

Common thinking that it belongs to rural areas is also wrong. There are whole cities built

from earth, for example the city of Shibam in Yemen, with population density comparable to

Manhattan. Earthen construction can be also very durable. The oldest existing examples of

such structures have thousands of years and some are still occupied by people. Centuries of

tradition enabled people to develop structures varying in shapes and purposes, that are also

fitting into climate and local conditions.

. 19. ' , ,

. 20. , , A


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Lets have a look at the modern era and development of earthen construction

nowadays. There is a number of architects, that had a great influence in popularising

buildings from earth among people in western world. One of them is Francois Cointeraux.

French architect living in XVIII and XIX century. He discovered pise de terre (the rammed

earth structure) and began making building for rural French countryside, that was suffering

from wars. He made a wide range of proposals for poor and the rich, in urban and rural

areas, all of which were made of fire-proof rammed earth technique. Despite the fact, that he

was rejected and set back by masonry and carpentry craftsmen, he left a great deal of work,

from which modern architecture could take inspiration. Architect like Antoni Gaudi, Adolf

Loos, and even Hitlers architect, Albert Speer were interested in use of earth in common

building. Frank Lloyd Wright and Le Corbusier, who were ones of the most influential

architects of XX century, also were also aware of the potential of earth. Both made projects

for earthen assemblies, but they had to resign, because of the difficulties of war. Hassan

Fathy was another XX century architect, that struggled to popularise earth against modern

tendencies. He is considered as a father of modern sustainability-oriented architecture.

As earth is rich and diverse, that earthen structures can be various as well. There are

many types of buildings from soil, but we will look closer at the most popular and successful

building techniques.

Rammed Earth

This technique turns earth into solid walls. Building process can be compared to

building with concrete, but with use of soil instead. Construction with compressed earth have

a tradition of thousands of years. Some of the great monuments, like Chinas Great Wall or

Alhambra in Spain were partly built of rammed earth. Construction was used also byRomans, which led to tradition of earthen houses in areas of France and Spain. In America,

the technique was known before Europeans arrival, The Pyramid of the Sun is an example

of earthen structure that survived to our times.


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. 21. ,

. 22. A


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To build a wall from earth we need a soil with proper composition. Basically any earth

without humus has building potential, but to get the best hardness and resistance, a small

research is needed. The ideal mixture would be 15-18% of clay, 25% of gravel, 30% sand

and 30% silt. But basically 10-50 percent of clay plus a various size aggregate could work. If

the clay content is too much, a natural fibres, like straw or sticks can be added to avoid

cracking. In modern construction, cement, asphalt or lime can be added to strengthen the

wall and protect it from damp. Mixture should also have a certain moisture level. It shouldnt

produce any dust while pounding, nor stick to shuttering or tamping device. After preparing

the mixture, the earth is put into formwork. The shuttering define the shape of the walls and

allow to make openings in the wall. The earth is laid layer by layer and compressed either by

manual tools, or mechanical devices. The layer is around 10-20 cm and it should be reduced

to half by pounding. The earth wall, if well executed is durable, but have to be protected from

damp. A high stem wall and big eaves can be a good idea to avoid moist.

Finished walls can have various aesthetical results. Articulation of layers can be

visible and even strengthened by different colours. It can have rough surface and visible

mortar, or be a plain wall with little variation of hue.

The earthen wall has good load-bearing properties. It provides good comfort, because

of moisture regulating characteristics and good heat accumulation. It has bad heat-loss

factor, so additional insulation or fibre content in mixture are often needed. The material cost

is very low, it can be usually taken directly from the site, but due to labour-intensiveness, it is

often uneconomical. The use of mechanical devices and modern techniques can improve the

construction performance. Pre-made earthen products begin to appear on the market as

well.

Mud brick

Mud brick, also called adobe, is a building technique that uses blocks made of soiland straw, which were moulded and left to dry. It is one of the most popular material used in

history, its beginning reaches 10 000 years past. The first world cities, like Jericho and Ur,

were constructed out of mud bricks. Earth served for erecting common houses, but also for

great monuments. Persian wonder, Arch of Ctesiphon, or pharaohs tombs in Egypt were

using simple mud in construction. Adobe can be found all over the world. As various is the

ground and people, the types and sizes of bricks are also diverse.


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. 23. A ( , )

Earth brick does not require any special soil to be good. Small coarse gravel, silt and

clay are basic content, but absence of any of the ingredients wouldnt spoil the brick

completely. To make high quality brick though, a certain amount of ingredients is necessary.

Perfect brick would have 2-7% gravel, 60-62% sand, 22-32% silt, and 14-15% clay. Straw, or

other natural fibre is another important ingredient. It helps in drying time, reducing cracking

while shrinking, and also reinforces the block. In different parts of world, some other

additions were used. Cactus juice, blood or manure are examples of supplements that add

better properties to the mixture. In modern construction, a Portland cement, lime or bitumen

are added to improve the quality. Once the mixture is ready, it has to be shaped. It is

common to use wooden moulds, put the mud inside, level it, remove the form and leave the

bricks to dry in a shaded place. It takes up to two weeks to dry and be ready for construction.

It is possible to mechanize the production, in some parts of the world it is even industrialized.

Mortar used in brick laying is the same mud from adobe production. Cement should be

avoided, as it is less elastic and can lead to cracking. Building does not require forms, the

shape of walls can be various and even vaults and ceilings can be done with earth blocks.

Physical properties of walls made of adobe bricks are similar to those of rammed

earth. Its natural, provide good comfort, but require additional insulation if used in colder

areas. The building process and economy are better in this case, because use of bricks is

more elastic and production can take place any time.


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. 24.

Another, modern version of adobe ( invented by Cointeraux in XVIII century) is a CEB

compressed earth block. It joins somewhat rammed earth and adobe technique. Produced

in the mobile presses blocks are strong, accurate and can be used just after pressing

process. It can be industrialized and it makes a good alternative material either for

developing and rich countries.

. 25.

( , )


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Cob

Cob is probably the simplest of all earthen building techniques. A mixture of clay,

sand and straw is piled up manually to create a wall, without any form. Because of its

simplicity, cob was used for centuries all over the world. For example: Taos Pueblo in New

Mexico is a village with multi-storey cob buildings, that is about 1000 years old and is still

occupied. Since XIII century cob was popular in England and from there it was spread

around the world during colonization period.

. 26. , , A

. 27.

To build a house from cob, we need a proper soil. The best mix would be around 25%

clay and 75% of various sized sand and gravel, not bigger than 0,5 cm. Straw should be

added till the point that the mixture is still coherent. Cob is supposed to be put on foundation

walls in lifts, that is layers about 0,5m high. Each lift is moulded and left for drying.


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Then another layers can be put. Openings are shaped as the wall grows, wooden lintels can

be placed in the wall after it dries.

Cob walls are often curvilinear, which is common for this building technique. The

perception of a natural wall with oval edges is very pleasant. It is the most sculptural of all

low-tech building systems.

Because of the composition of the wall, it has similar properties to the two mentioned

above. Despite its simplicity and charm, cob is extremely labour-consuming and also makes

poor insulation.

Other earthen materials

There are many other ways of building with earth. Some differ in composition of an

earth mix, some differ in the way of applying it for the walls. Some are good for hot climates,

some are suitable for winter. There are also many mixes of structures. Walls may either be

monolithic, or be a skeleton structure filled with soil. From many techniques, a few following

are traditional, interesting and still have a potential in modern construction.

Wattle and daub A very old technique, that uses sticks fixed in structural framework,

that are later plastered with mud. That makes a lightweight construction, unlike other earthen

structures, that are rather heavy. Wall rendered outside provides good shelter from sun and

the wind.

. 28.


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Earthbag The building is made of a sacks filled with earth. Bags are stacks one onto

another and often reinforced with barbed wire. Dome-like structures are later rendered

outside. This technique proved itself useful in refugee camps for people suffering from

disasters, like floods and earthquakes.

. 29 B ,

Turf structures Turf was used on roofs and in walls for centuries in northern

countries. Because of its porous composition it made well as an insulating material. A semi-

domed houses made of light wooden structure and covered with thick layer of turf made a

comfortable home in harsh winter climate. Today a turf roof is a green, well insulating

alternative for a normal roof.

. 30.


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Cordwood masonry

Cordwood masonry, or also called stackwall or log-end construction is a structure

using short-sized wooden elements. The wood is simple stovewood, that is usually expected

to be burnt in the fireplace. Instead, the elements are used to build a wall. Pieces are stack

like bricks and joined with mortar. In the most ecological constructions it can be even a clay-

based mixture. Cordwood was used to build houses in many parts of the world. It is hard to

estimate the beginning of this construction, but it is not difficult to imagine a wall, just by

looking on a pile of cordwood stored for burning. Surprisingly, this technique was used in

areas where there was plenty of forests, and therefore a lot of good quality wood for

construction. Still, cordwood houses could be found there. It was because using small

elements, like scraps from lumber mills, was way cheaper than normal timber. Although

stovewood masonry might be seen as a construction for poor people, it developed quite

sophisticated solutions, that enabled these buildings to last for hundred years. Nowadays,

cordwood masonry is beginning to play a important role in ecological, alternative

construction.

Modern stackwall structure joins insulation properties with thermal mass. It is built

with three layers. Internal and external layers are structural with wood pieces joint with

mortar, while space in the middle is filled with a loose insulation. Wooden elements are going

through whole wall, holding layers together. Mortar can be a normal cement-based concrete

or, which is more ecological, mixes using lime or clay. Sawdust can be added to aggregate,

to retard curing and provide additional insulating value. Wood used in walls should be

seasoned and hard wood species, like oak, should be avoided.


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. 31. , , A

. 32.

Cordwood wall, when not plastered, has a unique aesthetics. Visible woodenelements can be whole rounds or split. To protect wooden elements from damp, careful

detailing is required. It is also important to choose right wood and right mixture of mortar,

because of shrinking and cracking of a wall. Wood and cement have different properties and

work in different way. If log ends are exposed to the weather and able to dry in reasonable

timing, it is not prone to get rotten either.

Walls provide good climate inside and have good thermal mass keeping the heat.

Wood is hygroscopic, which helps to maintain balanced moist inside of a building. Building

process requires more work than usual wall, but the material cost is much less.


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Straw

Straw and hay was used in construction for hundreds of years, also as an addition to

cob and adobe, but strawbale structure is quite new. As agriculture went industrialized,

baling machines were used to manage the harvest leftovers. Since then straw became a

cheap and easily available material for walls. Nowadays it is probably the most common

,,green material. It is renewable, cheap, quite easy to build and provides high thermal

insulation. If we look more closely at the straws, they are hard, hollow and decay slowly.

Unlike hay, it is not eatable by animals. Basically it is a waste material and because of lack of

better use, it is often just burned.

. 33. , A

. 34.


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There are two main building techniques that involves strawbales. A load-bearing wall

and a skeleton structure with straw infill. First of them, called Nebraska style, uses bales as a

structure elements on which the roof is placed directly. Bales are laid like bricks, and get

compressed with roof load. It is a simple method, but requires careful detailing and a long

time to be exposed to weather, before plaster can be rendered on the wall.

Another method is usually a wooden post and beam structure with space between

columns filled with straw. It is more loose and provide better insulation. Often the building

process takes place under existing roof, which reduces the chance of straw getting wet.

Whatever is the technique, it is necessary to plan and execute the wall correctly. It is

extremely important to keep the straw away from moist. Wet straw catches mould and fungus

very easily. Bales should be raised from ground on stem walls to avoid ground moist and rain

splash. It need to be rendered with plaster that allows air to pass by. Large roof overhangs

also help to keep the damp away. Careful detailing and execution is a must. Also the

strawbales should be selected with attention. The best is local material stored in dry place.

Finished wall has very good thermal properties. Straw is also nontoxic and

hygroscopic, which contributes to good indoor climate. Thick walls provide good sound

insulation as well. Many people like the aesthetics of a strawbale wall, with soft edges and

unique contour. Like in case of previously mentioned materials, straw is cheap in cost, but

more expensive in labour.

Living roof

When it comes to sustainability, the green roof is the best choice. It has several

advantages proving that it is better than normal roof. First of all it is durable and long lasting.

The soil and plants make a great protection from UV rays from sun, heavy rains and

mechanical damage. It makes good use of rain and reduces the amount of stormwater

directed to sewers. It helps combating the heat island effect in the cities by consuming theradiation instead of reflecting it. Due to its mass, the living roof has good insulation

properties and thermal mass. It helps to reduce conditioning expenses, because of water

evaporation cooling effect. It makes a good insulation against cols as well. Green roof is not

toxic, used materials have smaller environmental impact and it naturally filter the rainwater.

Vegetation on the roof is a piece of nature on the building that helps to maintain balance by

allowing plants and small animals to dwell even in the big cities. It can be also a recreational

area for people and even a garden for growing vegetables. Not to mention that it is simply

beautiful.


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. 35.

There are many disadvantages however. First, it is a big initial cost of living roof. It

takes a lot of effort and money to build one, though long lasting time often compensate it.

Green roof is heavy, this load must be taken into consideration in projects and often is a

barrier for retrofitting on existing buildings. It takes a lot of work, careful detailing and

execution, to make it well. Repairing such a roof is very difficult. Intensive green roof requires

also maintenance work during its life.

. 36. ,


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Green roofs were successfully used for centuries in Scandinavia and other northern

countries. Nowadays living roofs gain more and more popularity. There are certain rules

being introduced, which encourage using them. There are even a living walls solutions in

recent projects. That brings green matter back to the areas possessed by men and proves

that it is a good alternative for traditional construction.

Other low-tech materials

Bamboo Is one of the most sustainable building material. It grows very fast,

therefore is highly renewable. For its weight is remarkably strong. It can be used either for

construction or for cladding. Structures made of bamboo are very light and can cover long

spans. The biggest problem with bamboo though, is the joinery. It cannot be joined like

wood, because it loses all strength when split or cut. As the scarcity of wood might progress,

bamboo can make a good alternative.

Paper this popular material can be used in buildings in different ways. Recycled

newspaper can make a good insulation. Popular method is to pump such loose paper pulp

into cavities in the wall to fill the space very tightly. Another idea is to use paper tubes as

load bearing structure in small buildings. There is also a invention called papercrete, which is

a mixture of recycled paper, little amount of cement and water. This mix can be used either

to produce paper-adobes or to be poured into forms. It creates lightweight and highly

insulative structures. Of course in every aspect of using paper it is very important to keep

water away from the material.

Recycled materials If we want to think green, it is a very good idea to use reclaimed

materials. If the energy was already spent to produce a certain material, why not to use it

again, instead of letting it be thrown away? Whats more, some of this things one can get

even for free. There is a wide variety of materials that you can recycle, starting from

traditional building materials like bricks, tiles, timber, steel elements, stones. We can also

experiment with any material that could be potentially used. There are known examples of

using:- Post-demolition leftovers like crushed concrete, broken pavement slabs (so called

urbanite) can be used as an aggregate or brick-like elements.

- Tires filled with earth can make a durable and strong foundation wall.

- Elements of a railway track

- Lumbermill leftovers

It might appear that only imagination is the limit, but sometimes the poor quality and amount

of work put into turning the material into usable good, prove that it is not worthy.


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. 37.

. 38. ( , A)


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III. Low-tech in modern construction: cost

Is it worthy to build low-tech? The best way to show the advantages and

disadvantages of such choice is to compare a conventional house with low technology

house. For this purpose lets choose a strawbale building, as a most spread natural building

system with many successful realisations. It seems to fit well into modern building

requirements and codes.

There are two general ways to build a house in this case. First is mostly used by

people devoted to ecological ideas. They build a house by themselves with help of friends

and volunteers. Contractors are hired only to execute tasks beyond eco-builders skills. In

this scenario house costs may be significantly lower than in conventional construction,

because of low cost of materials and almost no cost of labour. Of course this way is very time

and effort consuming. Sometimes it takes years to get the home finished. Yet, for some

people it is an adventurous and exciting process of building a dream house.

Another, traditional way is to hire a contractor to build a house for a client. In this case

one have to pay for labour. Although material costs may be very low, a complexity and work-

intensiveness may lead to higher costs. It might also be difficult to find a company that is

used to build from strange materials.

It is hard to estimate the cost of a strawbale house, because it depends form a lot of

factors. There are some general ideas though. The material cost of a strawbale house is very

low. It takes a few hundred of bales to build a medium-size building, and normally it closes

below 2000$. If contractor is familiar with this construction, the building time and labour

doesnt have to be more than a conventional house. There might be problems with interior

installations though. It is a rough estimation that construction cost is similar to the normal

building. But another factor, maybe the most important, is energy consumption during the life

of a house. A strawbale house might endure hundreds of years, if well protected. The thick

external walls filled with insulative material, that is straw, have very good properties. It is

proven that U-value of a 40cm wall made of straw is around 0,12 - 0,14 Wm

2

K. It is waybelow the standards and can lead to great energy and money savings. Passive solar design

fitting to the climate might enhance the performance even more.


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Here are results of researches for energy and cost for different houses in USA:

Life cycle cost of four homes, Fresno, California:

Conventional Straw Bale SB Solar Self-built SBS

Construction cost $112,000 112,000 112,000 42,000

Finance cost annual $3,500 3,500 3,500 1,344

Heating and cooling annual $37,868 24,892 5,893 5,893

Utility cost annual $1,555 1,021 241 241

Lifetime cost comparison (100 years):

Conventional Straw Bale SB Solar Self-built SBS

Dollars 1,001,300 935,200 843,300 347,700

CO2tons 930 600 140 140

Energy modeling by Jennifer Rennick, energy analyst, San Louis Obispo.

Life cycle cost estimate for conventional vs. strawbale houses

Construction Finance Energy Total Savings

Conventional $82,500 396,000 120,000 532,500 -

Straw Bale $78,375 376,000 60,000 451,675 83,875

Straw Bale self-built $40,000 192,000 60,000 260,000 272,500 Life cycle - 100 years

Finance cost construction cost minus down payment of 20% at an annual rate of 6% over

one hundred years of life cycle.

Energy average cost of heating and cooling

Total amount of down payment plus energy and finance

Working group reports, Plastered Straw Bale Conference, Roots and Revival, Arthur Nebraska,1993.

The advantages of straw construction seem to be obvious. If you add the conclusionsabout environmental impact, locality and ecology, that were mentioned in previous chapters,

the question appears: Why not to build from straw? Fortunately more and more people are

asking themselves this question and ecological construction is growing consequently.

This is for a strawbale construction. And what about other natural building materials?

As less popular nowadays, the actual research might be limited. Structures like earth appear

to have less potential, due to poor insulation and high labour-intensiveness. Nevertheless

examples of such structures seem to develop and grow as eco trend in architecture gains

more and more field.


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IV. Summary

A low technology, sustainable building can be understood nowadays as a

construction that is:

- Adequate for the climate and place where it is located

- Using passive, simple solutions providing comfort and avoiding high-tech active

systems.

- Using natural materials with low environmental impact, collected locally.

- Easy to recycle or return to the environment, when demolished.

Should we consider building this way? Is it really worthy? Low-tech houses might seem to

be easy to build, but in fact, to make a home fulfilling todays demands for services and

comfort, it takes a lot of effort. The proper knowledge about old technologies, history and

local conditions is required. Then a good design is needed, that compromises traditional and

modern achievements. Only copying vernacular architecture, without using todays practical

knowledge might be a mistake. Then a skilful constructor is needed. It can take a lot of effort

to find someone capable of building a modern house in antique way. Legalising construction

might also be a problem.

Although all this effort, the result is often worth it. A house that is ecological and

connected either with nature and with people, who dwell inside. It is a practical simplicity as

an alternative to modern, fast and resource-consuming construction. In many cases it can

also prove less expensive that conventional building.

Now, if we look into the future, the idea of making low-tech houses might develop into a

important part of construction. As ecological movement is becoming trendy, natural materials

can be used more frequently and it can lead to industrialisation of certain techniques. Then

the prices can go much lower. Low technology structures are already used for refugee

camps or houses for victims of disasters. Another step can be a low-cost social housing in

urban and suburban areas. But this construction mustnt to be connected with poverty. It canbe simply a cheaper solution for a house for everybody. Even luxury homes can be built low-

tech with comfort comparable to a conventional houses. Ecological construction is good not

only for environment, but also for people. Hopefully, more people would see advantages of

such structures and soon we will all live healthy and happily.


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Bibliography:

Berge Bjrn, The Ecology of Building Materials,Second Edition, Architectural Press,

Oxford, 2009

Broome Jon, The Green Self-Build Book, Green Books, UK 2007

Dahl Torben, Climate and Architecture, Routledge, UK 2010

May John, Handmade Houses & Other Buildings, The World of Vernacular

Architecture, Thames & Hudson, London 2010

Lynne Elizabeth, Adams Cassandra, Alternative Construction: Contemporary Natural

Building Methods, John Wiley &Sons, Inc., New York 2005

Rael Ronald, Earth Architecture, Princeton Architectural Press, New York 2009

Snell Clarke, Callahan Tim, Building Green, Lark Books, New York 2005 Vitruvius, The Ten Books On Architecture, translated by Morris H. Morgan PhD.,

LL.D., Dover Publications, Inc., New York 1960

Wanek Catherine, The New Strawbale Home, Gibbs Smith Publisher, Layton 2003

Web pages:

http://biobudownictwo.org/koszty-budowy/koszty/ (Nov. 2010)

http://en.wikipedia.org/wiki/Green_roof (Nov. 2010)


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Illustration Index

Illustration on the front cover: A Low-tech building (Rosie Joe House, Utah, USA)


il. 39. Low-tech house from cob (Simons house, Wales)http://tinyhouseblog.com/earthcob/simonshouse/

il. 40. Earth house, Switzerland

http://www.bukisa.com/articles/37063_10-unique-houses-from-around-the-world

il. 41. Climate zones in the world

http://climatezonemaps.com/images/climate_map_3.jpg

il. 42. Panorama of Cairo

http://www.pylos.pl/web_images/kair.jpg

il. 43. Ventilation scheme for town house


il. 44. Traditional Japanese house

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e81aae8d.jpg

il. 45. Ventilation and shading scheme for Japanese house


il. 46. House in Datca, Turkey

http://www.datcaturkevi.com/images/img_0882.jpg

il. 47. Turkish house shading scheme


il. 48. Village of Snderho, Denmark


il. 49. Igloo cross section


il. 50. Swedish log house

http://www.swedishlogcabins.info/images/

il. 51. Log house cross section


il. 52. Rectangle and triangle solidity scheme (by author)

il. 53. Simple arch

http://www.carolina.com/images/en_US//local/products/detail/76-4010_phy.jpg

il. 54. Dome of Pantheon, Rome

http://lh6.ggpht.com/

il. 55. Earthship building using tires in construction (Taos, USA)

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e87b9839.jpg

il. 56. Energy intensive steel production

http://blstb.msn.com/i/94/E425349C3689DBB6FFB1B26E8F6F.jpg


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il. 57. World's biggest mud brick building, Great mosque of Djenne, Mali

http://www.treehugger.com

il. 58. Traditional building, Santa Fe, USA

http://www.santafetrailnm.org/site148.html

il. 59. Modern rammed earth building, FranceRael Ronald, Earth Architecture, Princeton Architectural Press, New York 2009

il. 60. Appearance of earthen wall

il. 61. Adobe house (Camacho residence, Mexico)


il. 62. Mud brick production

http://farm1.static.flickr.com/125/321338240_954c6c424a.jpg

il. 63. Wall made of compressed earth blocks (Center for the blind, Mexico)


il. 64. Cob house, Oregon, USA

il. 65. Inside of a cob house

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e88a4d1f.jpg

il. 66. Wattle and daub wall

http://www.wealddown.co.uk/

il. 67 Baninajar Refugee Camp housing, Iran


il. 68. Icelandic turf houses

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e8b04ad7.jpg

il. 69. Cordwood building, NY, USA

Snell Clarke, Callahan Tim, Building Green, Lark Books, New York 2005

il. 70. Construction of a cordwood wall

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e8b7c77c.jpg

il. 71. Modern straw house, USA

http://www.tpr.org/articles/2007/09/strawbale_house.jpg

il. 72. Strawbale house under construction

http://org2.democracyinaction.org/o/5035/images/MBB%20images/

il. 73. Green roof on one of the buildings in New York

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e8c471a0.jpg

il. 74. Houses with living roof, Faroe island

https://reader009.{domain}/reader009/html5/0302/5a983e6d32859/5a983e8cf2bc0.jpg

il. 75. Shed with bamboo roofing construction

http://www.greenhomebuilding.com/images/booksetc/

il. 76. Paper building (Carriage house, USA)

http://www.earthbagbuilding.com/images/plans/carriagehouseS.jpg

Marcin Kulesza Dissertation Low Tech

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