Un-burned clay



Clay has low balance humidity and good treatment of humidity. Dry clay works good with wood and other organic materials preventing decompostion of these materials and clay equalizes effectively variety of humidity in indoor air. Clay ”breathes” and it is fire-resistant, massive clay construction isolates sounds very well and it is good material acoustically. Clean clay is odourless and it doesn't excrete harmful substances for health and clay prevents electromagnetic radiation. Massivenes of clay helps to keep the room temperature equable and gives a possibility to store energy. Clay has good compression strength and clay constructions can be build self-directed when there has been specialized quidance. Clay can be recycled and disposal of clay is trouble-free (demolished clay construction material is possible to use again or clay material can be disposed returning clay back to natural cycle).


Primarily un-burned clay can be used as construction material, for example bricks, bars, plastering, clayplates and decoration materials.


Clay is found plenty from Finnish soil, especially in South-West-Finland there is excellent construction clay everywhere.


Clay building in Estonia

Estonian clay building traditions are not very long, but out experience goes back at least a century and a half. Estonian building can be divided into four periods:

First period: 1850 – 1870. Buildings were built without a fundation.

Second period: 1870 – 1900. Mainly, farmhouses were built, foundation and wooden window and door frames appeared.

Third period: 1906 – 1914. The houses from this period have door and window frames made from concrete.

Fourth period: 1920 – 1930. Clay building appear to towns. There are many survived to this day in Tartu.

In Estonia, the clay building traditions have particularly rooted in the southern counties. Perhaps the difference between the soil is important here – in South-Estonia, very often it is possible to dig the clay directly at the building site, which made building from it especially easy.

 The tradition of building from clay has preserved in Estonia, but in many European countries, the appropriate know-how is no longer in circulation. For making adequate research, the historical background as well as good prospects for using the gained information successfully in practice, is available here. The Estonian University of Life Sciences’ Institute of Forestry and Rural Engineering is currently active in researching the area – they are observing the mechanical and thermal properties of clay mixture containing different fillers.


The properties of clay

From its properties, clay is a very healthy and a good building material. As clay has the characteristic of regulating and balancing the relative humidity, the microclimate of a clay building is always warm and dry. In contrast to the cold and clammy microclimate of a stone building. From the position of wood constructions, using clay is the exclusive thing to do, because due to clay’s lower humidity the dampness moves from wood to clay. Noteworthy are also the thermal properties of clay, which, for instance in the case of light clay, meet every modern building regulation. In addition, clay is architecturally a very good material, as it is easy to create round and streaming forms with it. The biggest disadvantage of clay walls is their resistance to water, because water, that is flowing on the wall, can cause holes in the wall in a really short time.

Clay walls are 100% recyclable and as a waste, they are completely safe for the environment.


Different construction methods

Massif clay is the most common form of clay construction in Estonia. Its principle is that clay is being stamped between the wall’s wooden holders or the layers are placed on top of each other. As an adhesive, roots, branches, heather and hashed straws are being added between them. Building this way helps to retain the wall’s loadbearing function, so simple buildings do not need a timber substructure.

Light clay construction technique has gained popularity in recent decades. Its name derives from the large proportion of adhesives added to the clay. Sawdust, wood shavings, flax bones, hashed straws, hemp, broken thatch and heather stems are the main adhesives added to the clay. Walls constructed in such a manner have very good thermal properties that also respond to present-day building regulations. Walls may be constructed by shedding them between the holders as well as from blocks. The loadbearing structure of a light clay wall is made up of wooden framings.

In addition to the above-mentioned methods of construction, it is possible to see also walls made from unburnt bricks and walls from clay and billet. Similarly to burnt bricks, the construction from unburnt bricks goes like conventional masonry, where the adhesive is clay or lime mortar. Billet-clay walls on the other hand are quite peculiar. Basically, the billet-clay wall is like a woodpile that has been put together with clay.


Using the following references in Estonian, you will find lots of necessary information about clay construction services, history, training courses, masters, teaching materials and research services.


Information about light clay and clay blocks and construction service



South-Estonia’s traditional clay construction: condition, expertise and the revival of clay construction traditions. About clay construction’s history, problems and solutions



The masters of clay construction, clay work



Article about the history of clay construction and its tradition in Estonia



Historical manuals about clay construction. Educational materials (PDF)



Historical clay construction manuals (PDF)



Clay plaster, light clay buildings. Information and constructional service



Information on how to build small buildings from clay, sand and straws, informational and educational materials. Master’s contacts



Hea Maja Pood – traditional and natural building and finishing materials, tools, guidance, trainings



OÜ Saviukumaja – clay and lime plaster sale, the restoration and improvement of clay houses, constructing clay buildings, clay and lime plaster works, clay blocks, paintins with natural paints



Information Centre for Sustainable Renovation



MTÜ HääOm – masters and trainings



Safran – sale of natural finishing materials



Estonian University of Life Sciences’ rural engineering research services



Tarmo Elvisto, the director of Information Centre for Sustainable Renovation, shows how to fill the gaps between logs and what good properties the Estonian clay plaster has. Video.



NB! Businesses whose websites have been mentioned are not in any way privileged. All of the businesses are not the very best and they might not have quality goods. Their websites do not give full information; the client has to be careful and gather additional information about them. The quality of the websites might not correspond to the quality of their goods and products.


Estonian clay building overview written and links collected by Viljar Pihus & Oliver Tätte, Viljandi Cultural Academy. Main text source: Kristina Akermann, "Clay as local building material".


Some words about Gyürüfü ecovillage and local claybuilding


A few words about Gyürüfü eco-village and local claybuilding

A hundred years ago Gyürüfü village had about 200 residents who were quite well-off financially. During  the Hungarian Soviet  Republic, the village remained outside of the active societal exclusive economic zone, and the region was regarded as poorly accessible and without  a future perspective. No development support was given. The same fate also befell many other Hungarian villages in more isolated places, and at its downfall there was mention of the inevitable fee of progress.

The rebirth of the village began in the early 1990s, when a group of students with green ideals rediscovered the area, created the Gyürüfü Foundation and signed a contract with the local government for the use of 174 ha of land. The aim was to create an independent and sustainable community which would advocate a natural lifestyle with traditional building and agricultural technologies used on site.

The Gyürüfü Foundation is an independent environmental organisation which focuses its activity on the local watershed situated in the southern hills of Zselic, a hillside range in Hungary. The foundation was registered in 1991, and has no affiliation to any of the political parties or business enterprises except those established by the eco-villagers. The mission of the organisation is to develop a well-founded, realistic and feasible small-scale model of human subsistence with an emphasis on environmental and ecological considerations, seeing rural areas, hamlets, villages and agricultural farms as the first priority. Special attention is paid to information technologies and telecommunication, as less harmful options through which the necessity to take advantage of polluting and damaging technologies can be avoided. The concept considers the initiative not as an individual and unique implementation of the principles, but rather as a model, an experiment which might have a positive influence on the mainstream regional development schemes of the future. The foundation also makes and attempts to care for and tend to social, human and community values. It does not ignore or neglect natural beauty and values, cultural, social heritage or landscape features of the small-scale local region while trying to retain its holistic and interdisciplinary approach.

Today Gyürüfü is home to eight families, with a total number of about 30 residents. The expansion of the village continues, the  aim is to have a number of residents between 200 and 300. The villagers try to  move towards a completely independent economy –  about two thirds of the necessary energy for vital functioning is already received from local renewable power sources, and solar batteries aid in getting electricity. Husbandry and gardening flourish, villagers try to grow all vegetables themselves, meat and dairy products are bought from surrounding farmers.

The concept of the Gyürüfü eco-village is – apart from developing organic farming completely free from chemicals - also to act as collector and moderator of information about sustainable building technologies. Guests are invited to the activities of the different workshops. The results are introduced to the public and the village attempts to take part in the work of the international network of practitioners.  They accept tourist groups, and there are several forest paths for children.

The houses in Gyürüfü village are built using a special, traditional building technology based on light clay, a technology developed over hundreds of years. The specific character of the local light-mud allows building to be executed in the same manner as bees work, in massif technique using frames of planks that are successively raised along the wall. Compatible building material is found in abundance, right on the building site – under the 20 cm thick humus layer there is a clay layer of about half a metre, and under this clay layer a layer of light-mud suitable for building in massif technique. These buildings have walls that are three-quarters of a metre thick in material that matures quickly and cheaply, is very warm in the winter and offers sufficient protection from the summer heat.  The work in erecting the clay walls of a 50-60 m2 house takes 20 professionals a long working day. The thickness of the walls varies from 60 cm (outer walls) to 40 cm (inner walls). A 25 cm tall wooden frame is raised on the foundation to make the wall, after which  the gap is filled with slightly moist material which is immediately stamped into place with a special wooden rammer taken straight from the trench. The frame is then unstitched, and every  ¾ metre iron poles or ½’’ pipe stumps are placed on the wall part, the frame is placed on them and the adding and tamping of material continues. The moisture degree of the material added to the frame is very important. Its suitability is decided by touching it with the hand. The falling test can also give you an idea – a mud ball clenched to the fist mustn’t  break when dropped from a height of one metre. It is a very common technique in Hungary, there are farmhouses built in this manner on approximately 60% of the territory.

Hard clay bricks which are used in stove-building are made on the spot. Plastic, metal and concrete are used in construction only when it is absolutely necessary, mainly in establishing utility networks. The entire water-supply , from wells and waste water cleaners to the sun collectors producing warm water, is thought-through and economic. For getting warm water in the winter, specially constructed stoves are heated with wood.

Report by Madis Rennu,

Viljandi Culture Academy

Gyürüfü village contact details:
Postal: Helesfa-Gyurufu Pf.3
Gyurufu H-7683
Phone: +36 73554412

Clay as local building material



Text by Kristina Akermann

Clay construction techniques have been known for over 9000 years. Clay has been used as building material in all ancient cultures,  not only for residential houses but for religious buildings as well. Even today, one third of the world’s population live in clay houses, mostly in developing countries with a hot and dry climate.  Clay is the most important local building material in the world to this day.

In Estonia, the history of earthen buildings is not very long, but we have some experience and expertise nevertheless. The history of Estonian clay building can be divided into 4 periods:

  • The first period lasted from 1850 to 1870.

In that period, buildings were without foundation and the houses were built mainly by using cob technique.

  • The second period lasted from 1870 to 1900.

In that period, clay houses were still mostly farm houses, but now they had foundations. Window and door  frames were made of wood, and the houses were built using the so-called pise´technique.

  • The third period lasted from 1906-1914.

In that period residential houses were also being built and window and door  frames were made of concrete.

  • The fourth period lasted from 1920-1930.

Clay buildings were also built in the cities, Tartu still has some buildings made of clay today.

In Estonia, the clay building tradition can be divided into two regions. There are lots of  clay buildings in southern Estonia and a long tradition of using clay as building material (many of the buildings are still in good condition), but in the northern part of the country, the tradition of using clay as a building material didn’t develop.

So why have people used clay as building material throughout history? Because it has been available in most regions, and because it  is a cheap building material mostly obtained directly from the building site.

Clay has many advantages as building material:

  • Clay constructions preserve timber and balance air humidity
  • Clay constructions store heat
  • Clay constructions have a low embodied energy
  • Clay constructions save on material and transportation costs
  • Clay constructions are ideal for DIY construction.
  • Clay constructions are reusable

But it also has its disadvantages:

  • Clay is not a standardised material
  • Clay constructions shrink when drying
  • Clay is not water-resistant.

Estonia has a tradition of clay constructions, but like in many other European countries unfortunately  the know-how is disappearing, which is why we need to promote clay as a building material. We need to study the old traditional techniques and develop new innovative techniques to build houses with loam. And that is what the Estonian University of Life Sciences (EMU) is doing.

One of the EMUs research fields is loam and clay buildings (both old ones and new). We are studying their thermal and mechanical properties and developing simple methodology for identifying loam and its suitability for clay plasters and lightweight clay, to find out the ideal, or at least the most appropriate, composition of clay plasters and clay blocks.