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With natural, low-emission building materials and home furnishings



Wood has a natural healing effect on us humans. Numerous studies and tests have shown that spending time in the forest and in a solid wood environment lowers the pulse rate, has an anti-inflammatory effect and ensures better sleep.

So-called healing forests are springing up like mushrooms in Germany. They are designed to help people regain their health, find peace and relaxation.

Wood is sensual. It feels warm, smells good and creates a sense of well-being in a wooden house. The overall living climate of a house is made up of many individual factors. Whether we feel cosy and comfortable in a house depends on all of these. No sweating in summer, no freezing in winter: This is what ideal thermal comfort feels like. A perfect feel-good climate. The diffusion-open construction of solid wood walls makes it easy to keep the indoor air temperature and humidity at the right level. Both factors influence the room climate.

Just like the air movement. Outdoors, a little breeze can refresh the air pleasantly.

Indoors, however, the situation is different. Some draughts in the room quickly blow away the cosy feeling.  The special construction of timber houses means that they fulfil the requirements for air and wind tightness in accordance with DIN 4108. Additional measures are only required for buildings with higher requirements, such as passive and efficiency houses.


Odour sensitivity

If odours occur when entering rooms that can be traced back to material leaks and cause discomfort, then processed solvents in adhesives and paints may be responsible.

In the case of indoor air quality in solid wood houses, this question does not even arise. Everyone is also well protected from unpleasant sound or disturbing noise. These are all factors that influence cosiness. Just like a suitable room layout, good lighting, pleasant colours and the choice of interior materials.

It is therefore important to ensure that no glue or other chemicals are used during the entire manufacturing process. This means that no unpleasant or unhealthy odours or vapours are inhaled. Provided, of course, that outgassing ceilings, roof trusses, paints, furniture and plastics are also avoided.


Solid wood houses are ideal for allergy sufferers

as natural wooden surfaces have an antibacterial effect. This prevents germs from growing on the surface. Wooden surfaces are also antistatic and raise less dust. All you will feel and smell is wood.

The ideal humidity in a house is between 50 and 60 per cent. Wood is as clay a naturally moisture regulator. It absorbs moisture and releases it again if it is too dry. Such regulated indoor humidity has a positive effect on the respiratory tract, eyes and skin.

The solid wood wall also offers you advantages in terms of radiation protection: Together with aluminium grooved pins, the solid wood construction absorbs high-frequency radiation from outside (e.g. mobile phone transmitters). In order to achieve continuous protection, additional measures are recommended for all non-wall components such as roof structures, ceilings or windows.

There is a natural magnetic field on earth. It is regarded as an important organising and orientation factor for all life. Building biology research shows that the human organism reacts negatively to technically or artificially induced DC magnetic fields.

It is therefore important not to install any magnetising steel components that disturb the earth's natural magnetic field. Aluminium grooved pins are not magnetic.



Traditional clay construction with bricks is labour-intensive and time-consuming.


Use excavated material containing clay and turn it into an alternative concrete without adding cement. Earthcrete can be poured when fresh, hardens quickly and is suitable for use in floors and non-load-bearing walls.

The processing is similar to that of conventional concrete and utilises a similar infrastructure. This technology gives clay construction almost all the advantages of cement, but is around 2.5 times cheaper and 20 times more environmentally friendly.

ETH spin-off Oxara. A technical achievement of ETH Zurich
Gnanli Landrou from Togo, doctoral thesis under Prof Guillaume Habert


Challenges of the global construction industry

Energy and CO2-intensive cement production, the dwindling raw materials sand and gravel and the high cost of concrete, which is simply too expensive in many countries.

Sandcrete blocks, in particular, have since become widespread in Ghana and other West African countries. These building blocks, made of a lot of sand, a little water and a little cement, are moulded into cuboids using sheet metal or wooden formwork and then harden.

Depending on the production method and compaction, they achieve compressive strength values of between one and around 3.5 N/mm².

In terms of quality, the bricks are often not of sufficient quality and tend to break and erode due to the high sand content. The advantage of these bricks is their comparatively favourable price.

The problem with the widespread use of this building product is the high consumption of cement, one of the largest CO2 emitters in the world, and also the enormous amount of sand used.

The sand required is often extracted unregulated from riverbeds or illegally from beaches, leading to environmental problems and land loss, which particularly affects coastal areas.


Development of sustainable bricks with laterite

In an endeavour to avoid the consumption of sand and imported cement and at the same time offer an affordable, practicable building material, a brick was developed in 2015 that completely dispenses with sand and saves 60% of the cement.

Laterite earth is found in large parts of West Africa and is available in abundance.

These sustainable bricks consist mainly of laterite, a fully weathered and characteristically red earth. During the manufacturing process, they are pressed under pressure to form a moulded brick that is mechanically interlocked with adjacent bricks. This means that mortar does not need to be used between the stone layers during the construction process (so-called dry masonry).

Laterite earth is a widespread surface product in West Africa and is a by-product of (open-cast) mining, for example, or can be extracted during earthworks or levelling on the site to be built on and processed into bricks.

Due to the interlocking of bricks, the flat dimensions and the absence of mortar, they can also be laid by people who have no specialist knowledge in the construction sector. Training or instruction by a specialist on the building site is sufficient.



Nowadays, a large proportion of building materials are imported to Ghana.

This also includes cement and cement clinker, which are exclusively imported to Ghana, often from China.

After the heyday of West African tropical architecture in the 1950s and 60s, whose architects aimed to use modern building materials sustainably and adapted to the climate, traditional materials and construction methods as well as ideas of tropical architecture have been increasingly displaced since the 1970s.

This displacement was primarily due to economic reasons and a shift towards privatisation policies. The increasing popularity of Western-style architecture, which is considered modern and prestigious in Ghana, intensified the move away from the more favourable construction methods.