Category Archives: Green Building

Green building

Green building or low impact building is a set of techniques and materials which objectives are a reduction of environmental impacts. Are taken into account the level of embodied energy, the lack of pollution and green house gas produced during extraction, recycling or in the use of materials, the level of energy necessary to produce comfort in your habitat.

Green building philosophy in Permaculture does not limit itself to the construction of an habitat but tends to integrate this habitat inside the ecosystem and involve beneficial interactions from and to the ecosystem. The house will be the central node of logistic , redistribute the waste (considered value added resources for food production if properly managed), capture the rain water which can be redistributed by gravity, need to be protected from or take advantage of the heat, the cold, the winds, the rain, the various pollution if any, etc. Usually a house and its close satellites are the center of energy where most of nutrients transit and where are located most of the  functions of processing and storage. The location of the house will rarely correspond to the best initial view or esthetic integration but to various factors like water contention, slope, protection, circulation . The landscape esthetic surrounding the house  will follow naturally over time with the creation of a highly domesticated garden in zone 1, the closest to the house.

Green building depends on the context where you live and one technique which can be found quasi everywhere is Adobe building. It is based on clay, a material found in most parts of the world.

There are various techniques of construction using clay. Each technique has pro and cons.

Super-Adobe which consists in filling endless bags is fast and flexible and allow an “organic” architecture (curves, domes, waves, …)

Simple Adobe technique consists in making bricks and use them, together with a clay and sand mortar for building walls.

Adobe makes it easy to include glass (frame-less windows) and allow precision together with the use of classical building technique. Adobe bricks can be prepared in advance either by using clay/sand mixed with water or using a press.

Another technique often used in Bahia is cob consisting in adding clay mortar on a framework made of wood. When done with precision the end result may be beautiful.

Reducing embodied energy is as well recycling local byproducts like rubbles or broken tiles.

Low impact development is as well using renewable energies and resources like water recycling and water solar heating.

Our training covers mainly following techniques

– Adobe bricks making
– Wall construction in Adobe
– Finish using sustainable materials including clay and sand
– Painting using sustainable materials
– Creating mosaics
– Working with wood (mortise, ankles, …)
– Ferro-cement (technique to build water tank structure using 10 times less cement than classical construction)
– Brown and gray water recycling, solar heating system, solar oven, rain water management, …

– and more…

Finish for Adobe and Cob

The finish layer with clay requires some preparation worthy the end result it provides. On the photo below is an Adobe wall recovered by a clay finish and clay painting.

Adobe-Finish-25

You may use two types of dung to make your finish; cow or horse dung. Cow manure has hardening enzymes although horse manure provides with very good fibers for your plaster cohesion. When using horse manure you may add wheat floor to make your finish harder.

My choice in this case is about resource availability. In the region no one use horse dung as an organic fertilizer for two reasons;

– Horse manure needs to be composted because high in nitrogen (due to the method of gathering which implies a mix with horse urine in the stable). Cow dung can be used as is as a fertilizer.
– Horse are given a lot of dewormers in the tropics, something you do not want in your compost. Only antibiotics are well degraded in the hot composting process.

Therefore horse dung is better used for adobe than for compost, and easy to find and get from farms. They can be gathered as well from the sand road when you are lucky enough to live in a place where horse riding is part of the local culture. You do not need important quantities of horse dung to make a finish.

If you get cow manure better to use it for your kitchen garden.

The proportions to make a finish mix are as following;

– 2 Bucket of horse dung
– 4 Bucket of mixture sand/clay in proportion of 20% clay / 80% sand
– Optional : 1 kg of flour

You may test the clay/sand mixture by applying a fine layer on a wall and see if it’s cracking. In this case add some sand.

Clay processing

The clay should be sucked in water to ease the filtering process. A very fine meshing is required.

Adobe-Finish-02

The mixture you get is very liquid.

Adobe-Finish-03

You may gather it in a bucket and wait 2 to 3 days for decantation. The excess of water will surface and can be easily removed from the bucket.

Adobe-Finish-05

You obtain a very fine mixture with a low proportion of sand (only very fine sand pebbles have gone through). This is the main reason you need to add sand although your soil could be already in the correct initial proportion of 20% of clay and 80% of sand.

Sand processing

The sieve for sand needs bigger meshing. The sand needs to be dried so to ease the filtering process. It is worthy to store some sand in a location ventilated and protected from the rain one week before.

Dung processing

The dung needs to pass through a sieve as well, with bigger mesh. The filtering process separate long fibers from the short one and help as well to obtain an homogeneous material. From the different tests performed it does not appear a real difference between using old and dry manure or fresh one. When the final mixture is kept wet for few days the enzyme activity improve the hardening of the plaster in any case.

Adobe-Finish-06

The residues of dung and clay can be mixed together (in proportion of 1/3 volume of dung and 2/3 volume of clay residue) to be used as a rough (still strong, thanks to the dung) mortar to fill holes for examples in location which need a better mortar. Usually the clay residue has higher proportion of sand which did not go through the sieve.

Adobe-Finish-10

Flour processing

This step is optional and should be dedicated to the parts of your walls where you need a very fine and strong rendering.

Whisk flour in 2 liters of cold water. You’ll obtain a white and consistent paste than can be diluted in 4 liters of warm water. The dilution can be done by passing first the paste through a large mesh into the hot water in order to remove the clumps.

Mixture

The mixture can be done in a large recipient.

Adobe-Finish-08

The color will become grayish, a bit like cement. If you put color pigment here be aware that you’ll need a big quantity of it and that the gray influence of the dung will ruin a bit the end result. If you want to have a colorful wall it is better to make a painting coat using clay as well.

Mixture for painting

The proportion are

– 1 Bucket of clay
– 1 Bucket of sand
– 1/2 kg of flower
– Color pigment powder; (you may mix various pigment to obtain the taint you desire)

Make sure you always use the same proportions of mixture and pigment in order to avoid color variations on your wall. The sand, this time, should be passed through a finer mesh than for the finish. When finished the paint can be dried under the sun and transformed in a powder for future use.

Applying the clay finish

Before to apply the finish you need to make sure that your wall is dry since the finish is more water proof and could prevent your wall to dry or at least slow down the drying process. Then you pulverize water on the part where you want to plaster and scratch the wall to increase adhesion.

Adobe-Finish-14

Fine finish can be obtain using a flexible spatula (you may use a piece of plastic from a detergent plastic bottle like in the photo below). It is always possible to water a previous work and rework the finish. An advantage of such technique.

Adobe-Finish-15

The end result before painting is as following;

Adobe-Finish-20

When painting the wall put 2 layers of paint, it will make a difference.

The wall should be dry before painting.

When passing the paint make sure it fills in the holes. Wait another day to pass the second layer of paint

When doing wall sculpture you should add layers of 2 or 3 mm max on top of each others to create relief and wait for the previous layer to dry every time.

Adobe-Finish-30

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.

Adobe_house_01Adobe_house_02

Adobe_house_03Adobe_house_04

Adobe_house_05Adobe_house_06

 

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.

Adobe_house_07Adobe_house_08

Adobe_house_10Adobe_house_11

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.

Adobe_house_13

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.

Adobe-house-16

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.

Adobe_house_12Adobe-house-19

Adobe-house-20Adobe-house-21

 

 

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.

Adobe-house-22Adobe_house_18