Las Malvinas ecoladrillo schoolroom

viernes, 8 de junio, 2012

Background

Las Malvinas es una comunidad cerca de Santo Domingo, en la República Dominicana. Hay más que 150 familias que se viven en esta escenario rural, al lado del un río. Por un voto de las manos, la comunidad ha decedido que el proyecto que se quieren más es que trabajemos juntos, con la cultura y deseos de ellos y con la tecnología inteligencia de nosotros, para construir una aula para la escuela, usando modos alternativos de construcción como "papercrete" y "ecoladrillo."

"Papercrete" es similar a bloques de concreto, pero estos bloques son de papel reciclado. "Ecoladrillo" se usa botellas plásticas y concreto para hacer paredes.

Hay un abundancia de ambos materiales (botellas y papel reciclados), y necesitan más espacio en la escuela. Entonces, váminos a trabajar con las materiales más locales y baratos para ayudar esta comunidad cumplir este objetivo mientras estámos apriendo a implementar modos de construcción sostenable.

"tropical maritime; little seasonal temperature variation; seasonal variation in rainfall" ^[1]

"The northern areas of the Dominican Republic tend to see the greatest amount of rainfall whereas the southern areas of the Dominican Republic tend to be very hot and dry."^[2]

"Temperatures range from 64 degrees to 90 degrees F., and humidity is extremely high."^[3]

"Hurricanes pose a great threat to the island. Routes and patterns of the hurricanes are unpredictable, but the greatest danger comes in August and September, when hurricanes can last two weeks."^[4]

"The average annual rainfall for the Dominican Republic is 150 cm."^[5]

Problem Definition

Criteria

Criteria and constrains are needed to determine the success of a solution. Criteria are weighted with 10 being most important and 0 being least important.

Criteria	Constraint	Weight
Safety	The classroom meets or exceeds local building codes	10
Reproduction Costs	The classroom costs less to construct than through the use of traditional local construction methods and materials.	8
Appropriate Materials	Building materials are local, alternatively resourced, and may be easily obtained by the community.	7
Aesthetics	The classroom looks good with the existing school structure while having a unique appearance that draws positive attention to its alternative construction.	7
Ease of Use	The classroom comfortably accommodates the most number of students possible for the given space, up to 35 students.	8
Community Interest	Maximize community involvement to develop their interest in the project, as well as their skills and knowledge necessary to replicate the project later.	10
Research and Development Costs	Spend no more than US$1000	5

Literature Review

Rammed Earth Floors

METHODS:

• At the Dancing Rabbit Ecovillage in Missouri, they made an adobe/rammed earth hybrid floor. On top of a plastic moisture barrier (protected on either side by a thin layer of sand), they laid 4-6 inches of compacted "road base mixture" which is comprised of clay, sand, and various sizes of gravel (allowing for more compactability). "We added a few inches at a time and tamped it in place by hand after spraying lightly with water." They then used their standard earth plaster mix of 6 parts sand, 2 parts clay, 1 part finely chopped straw, and applied a 1-inch thick layer to the floor. The plaster was troweled smooth, allowed to dry, and then applied 4 coats of linseed oil, each of which dried thoroughly before the next application. The last three coats of linseed oil were mixed with increasing ratios of citrus paint thinner. ^[6]
• Earthen floors refer to a layer of substrate dirt or sawdust that is laid down on top of a layer of fine gravel, which is then covered with a layer of clay or sand. The final step is sealing the newly laid floor with a layer of linseed and hemp oil. The result is a porous, supple and durable floor at less than a dollar per a square foot (including labor). ^[7]
• Though their specific ingredients and construction vary by location, the idea is the same everywhere: Take some dirt (with some clay content), add water, some stabilizing agents like sand and straw, and squish it until it's hard. Once dry, seal it with an oxidizing oil like linseed or hemp oil. ^[8]
• To get the right mix, experiment with a test area of at least 3x3 ft. The mix should be strong enough that it is not powdery when it dries, and it must contain enough fiber so that there are no cracks. Apply the mixture with a trowel in 1/2-3/4" layer. The material should come off cleanly and easily as you move the trowel across the sub-floor. If it sticks, there’s either too much clay or not enough moisture; if it won’t stick to the trowel, there’s either too much moisture or not enough clay. ^[9]
• Homeowners in a wet climate should put down several inches of gravel to enhance drainage. This can be a three- to four- inch layer of clay, sand, and gravel or crushed stone, on top of which lays the half-inch layer of finer mix. If you pour this supportive layer in a damp state—and even add lime to the mixture—it will dry and harden more quickly. ^[10]
• A typical earthen floor might include a 2.5-inch base layer of 70% sand, 30% clay, with handfuls of long straw for tensile strength. Once it is dry, the final layer will be installed and smoothed with a trowel, composed of a similar sand to clay ratio, but mixed with very short chopped straw. ^[11]
• "The floor area between posts must be higher than the outer area. The wall will be protected from rainwater that runs along the flat outer wall of the house. The mixture for the earth floor is earth, gravel and water/asphalt in a 10:2:1 proportion, respectively. Another way to build a good floor is to use pumice stone sand which provides a thermal insulation base for very cold or very hot regions." ^[12]

LINSEED OIL COATING:

• At the Dancing Rabbit Ecovillage, increasing amounts of paint thinner in the linseed coatings allow deep penetration of the oil into the floor:

1st coat - Only linseed oil 2nd coat - 3:1 linseed to paint thinner 3rd coat - 2:2 4th coat - 1:3

• Boiled linseed oil contains solvents and is highly toxic, while eco-friendly linseed oil can be expensive. “As a compromise, we take raw linseed oil and put it in the sun in shallow pans covered with a piece of glass, leaving a tiny air space. The oil pre-oxidizes and dries faster. It’s called sun-thickened oil.” ^[13]

STABILIZERS:

• The main categories of binders used for earth construction are (Standards Australia, 2002; Houben & Guillaud 1994; SAZS 724:2001, 2001) Portland cement, lime, bitumen, natural fibre and chemical solutions such as silicates. Benefits of cement addition is improved structural integrity, while a downside is reduced permeability of earthen mixture and thus natural ability of earth to allow passage of moisture throughout the soil mass is reduced. ^[14]
• Tests have indicated that there is an optimum lime dosage for a soil beyond which compressive strength decreases (Norton, 1997). The likely dosages are between 6-12% lime by dry weight and will increase as clay content increases (Houben & Guillaud, 1994; Montgomery, 1998; Norton, 1997). ^[15]

Ecoladrillo

• “Eco-bricks” are a free and practical building material that can be used to construct almost anything from small planters and walls to schools and homes. Especially for rural communities the eco-brick represents the most ecological solution to manage household and plastic trash. ^[16] "The best materials are ones that serve no second purpose, for example paper is recyclable, so things made of polystyrene, aluminum, all kinds of plastics and in general synthetic materials, are the perfect eco brick filling. A list of possible waste would include: food packaging old socks, razor blades, used up pens and markers, clothing tags, cotton swabs, and any piece of useless garbage you could imagine." ^[17]

• Bottle Construction ‘How-to’ ^[18]

• "In order to effectively stuff the bottles we had to train the families and children on the proper techniques. The trash inside has to be all plastic or aluminum wrappers—no dirt, paper, or cardboard. The trash and the bottle have to be dry and clean, and the bottles have to be stuffed as full as possible to provide the most thorough insulation." ^[19]

Structure

Exterior walls

• Lay out the wall location on the sub floor where the wall's bottom or sole plate will be positioned. Measure from the outside edge of the subfloor, the width of the sole plate plus the sheathing, if the sheathing extends to the sub floor; or the width of the bottom plate if the sheathing extends over the boxing joist to the concrete foundation wall. Snap a chalkline.

Select straight stock for the bottom and top plates, square of one end of each plate, and lay them side by side on the subfloor. If the plates have to be made out of more than one piece of lumber, make sure they join over a stud centre. Measure and mark the locations of the door and window opening centres, openings located from centres, partitions and studs. ^[20]

Marking Top & Bottom Plates

• Standard walls are 8' to 12' high. Older homes and warmer climates will have 2x4 wall studs.
• Wall studs are generally spaced 16" on center. The first stud will sit on the end of the plate. Measure and mark 15-1/4" from the end for the near edge of the second stud. From this mark make marks every 16" for the near edges of the remaining studs.
• Before starting the layout process, chalk line the locations of the walls and their window/door openings on the subfloor. These marks will enable you to visualize and check the project's layout before the walls are made. The chalklines also serve as guidelines when actually raising the walls into place. ^[21]

Assembling Walls & Corner Posts

• We usually assemble the wall on the floor, nail it together, then raise it into place. Working on a level surface is a major help in laying out the walls flush. Try to avoid assembling walls on the ground.
• Check- It's a good idea to check for squareness by measuring diagonally from the corners after nailing on each end and after each wall is assembled.
• Where two walls meet in a corner there needs to be some extra framing to make sure that there's something on each wall for the drywall on both walls to nail into. One wall at every corner needs a corner "post." Here are two ways to create one:

1) Add 2x4 spacer blocks between the end stud and then install an extra "corner stud."

2) Lay an extra corner stud sideways, flush with the inside edge of the bottom plate.

Once the corner post is secure, insulate the cavity before installing the sheathing. Once the sheathing is on and the wall goes up, the end of one wall section will cover the corner of the other making insulating impossible at that point. ^[22]

Plank and Beam Construction

• In the plank and beam framing method beams of adequate size and to support floor are spaced up to eight feet apart. Floors and roofs are covered with a two inch plank. These serve as sub-flooring and roof sheathing, and where tongue and grove is used provide a great finished look. ^[23]

Concrete Foundations

• With unstable soils, and it wet climate where re-enforced concrete is used with Masonry blocks walls typically have a 1/2 inch coat of portland cement applied to the exterior. Once set this is then covered with asphalt to resist water penetration of the walls by water. ^[24]

References

Template:Reflist