Adobe House

Adobe houses are low foot print constructions using healthy (wood, clay, sand, lime) and low energy embodied material

Material

The materials used for this Adobe house building are

– Eucalyptus beams for the structure
– Adobe bricks for the walls. Clay can be found almost everywhere therefore often available locally. Adobe bricks are made using clay, sand, straw and water.
– Only 6 bags of cement (for a 50m2 roof house), 110 concrete blocks and building remains for the foundations and the floor (being in a region with no stone, concrete blocks are used)
– Recycled panels are used for the roof. They are very lights, allowing to reduce the weight of the wooden structure therefore its cost. Coconut tree leaves are added on the top of the roof to reduce sun heat.
– Horse dung, clay, sand, flower and pigment are used for the coating and painting
– Ceramic tiles and mortar for the bathroom
– Piso Queimado for the floor
– Electricity and plumbing are done in a classical way. Integrating them in the walls is easy.

Process and structure

The construction is made starting by the foundations, the house structure and the roof. This way the Adobe walls will be protected from the rain and the floor can be used for Adobe bricks drying.

 

Walls

Adobe bricks are made in a process which involves the mixing of clay and sand in specific proportions (between 20 and 30% of clay for 80 to 70% of sand. The prefabrication of adobe bricks, letting them to dry before to use them, allows avoiding the shrinking effect impacting wall construction. It gives the possibility for example to integrate glass directly into the wall without a wood framework, not being scared that clay contraction could break it.

The masonry technique is pretty identical to cement. The differences are

– A mixture of clay and sand is used to joint the bricks
– This mixture is not toxic to the skin, can be handled with bare hands and can be kept for how long its humidity level is managed to have the right consistence
– Once jointed the wall structure get quickly stiff which allows to continuously build a wall without waiting (it is the case for cement) that the mortar get hard
– Sculptures and variations can be easily added to the walls

Adobe walls have approximately the same resistance to compression than concrete.

Floor

A Brazilian technique in floor building with low environmental footprint is “Piso Queimado”. It is made from cement, tile mortar and marble powder. The floor has 3 layers;
– “Contrapiso”, a rough cement made layer, 3 cm thick with gravels. The Brazilian soil where is located the house has good stability and does not require steel armature.
– “Piso”, a very regular and well leveled out layer of cement
– “Piso Queimado” itself, a colorful and shiny layer, 0.5 cm thick, including usually green, blue, red or yellow pigment. The result is both rustic and elaborate, combining fresh stone sensation and a very soft touch. Piso queimado can be used as well for kitchen worktop. Using white cement allows more vivid colors. The piso queimado is sanded and waxed.

Bathroom

Clay is easily molded in presence of water. Recovering the bathroom walls with ceramics allows a durable protection against humidity. The mortar used to glue ceramic does not retract when drying ensuring a hard and consistent layer between adobe and ceramics.

Wall coating

The “rebocco” (coating) for Adobe is made using horse manure (cow manure can be used as well, it has finer fibers), clay, flower (from wheat or from manioc depending on the resources available in your location) and sand. It contains very small fibers allowing a strong and elastic structure improving cohesion, as well as enzymes ensuring a long-lasting layer. These materials are filtered in order to reduce the granularity of the finish.

Painting use the same type of mixture replacing horse dung by pigment. 2 painting layers are necessary to provide with a good result.

Painting and finish can be made as well using another Brazilian traditional mixture;
– aerial lime
– pigment

It allows efficient covering, insect protection (lime) and a non uniform colors giving a natural rustic touch to the walls.

 

 

Movement, Light and air fluidity

4 factors are taken into account when it comes to temperature tuning and air flow;
– sun direction,
– air circulation for cooling, humidity tuning, and air quality,
– mosquito protection,
– security and privacy.

When taking into account theses factors following techniques can be used always having in mind resources saving;

– Air exchange can be made using overtures close to the top of the walls. Warm air can escape and cool down the house. The overtures needs to be made on each side of the house in the axes of the dominant wind coming from the seaside. The overtures should include bars for security purpose and a mosquito net to prevent mosquitoes and insects coming inside.
– light is provided either by glass panes directly embedded in the Adobe walls or by recycled glass bottles, making sure to take into account the organic imprint this material will give to the wall. The glass material need to be put in shadowy location to avoid direct sunlight which could increase temperature rapidly. Direct sunlight is used for the shower only, easing the humidity evaporation and warming the shower local to entice the usage of cold or lukewarm shower.
– Passage and privacy are provided using standard doors. They are located either inside or if opening outside then should be well protected by a veranda. Two types of wood can be used; termite resistant or not. In the latter case the house needs to be regularly used and checked to avoid termites settlements. In the former case the doors price imposes to spend some time looking for recycled doors or to build the doors from rough material.

These techniques permit to avoid costly windows and allow the multiplication of overtures for air or light flow circulation.

The adobe thermal inertia attenuate the temperature variations between nights and days, making the inside of the house comfortable. The air flow monitored with tissue or wooden (e.g. small pieces of bamboo canes along strings) made curtains does the rest.

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