This is a small cabin for a farm manager on an organic farm in Chiriqui, Panama
Finca Santa Marta has been producing quality organic produce for several years now in bamboo greenhouses.
This project is also a prototype for assessing construction techniques and the economic feasibility for larger prefabricated kit houses using the same structural techniques.
It is a 480 sq ft living space with an additional front patio area facing the view over the river.
This is a warm area of Panama. This cabin was built to allow maximum ventilation thru screened areas at the top of the walls and in the openings in the cupola. The roof is white and inside the house has 1/2″ foam insulation to control noise and heat. The outside 3 foot overhang has about 3/16″ foam insulation to reduce noise when it is raining.
The photos below do not show a fully finished structure.
We are working on low cost, environmentally sustainable, quality, and beautiful construction techniques using low embodied energy materials and very low waste.
The idea of a kit style house offers a reduction in labor costs due to efficiency of construction and prefabrication, consistent quality, and faster construction times with known termination dates. This project has determined that all these ideas are feasible. We have had a chance to work on techniques and have the project reviewed by structural engineers to ascertain the needed changes to bring this and larger structures into the permit process. What we have found out is that we can bring these buildings to market at very competitive rates compared to the present construction costs of buildings of equal quality. We are also able to construct them in record time. This building foundation to roof was done in three months with a skeleton crew. This was the (let’s be honest) cheap version, but we will be able to bring in our Affordable Home Kit houses at similar savings!
We will go thru the entire process of construction here, starting with picking up the treated bamboo and prefabricating the Cupola parts and the foundations off site. This project took 180 culms to complete with all structural, lathing, patio roof, and interior walls. We started by making the Cuploa, a smaller version of the full size structure. Since this was a small, very light structure, with few structural stresses, we welded the connection pieces out of re-bar. Actual permitted houses will need to have these pieces welded with bar that is designed for structural welding.
The welded steel is now inside of the center of the roof which is tied together till a stucco mix can be poured into the top section of the bamboo culms. At the lower end of the roof, it is connected using these welded bars. These are also drilled and filled with stucco.
As seen here, Danilo is filling the cavities with a stucco mix. Holes are drilled into the last section of the bamboo and a 2″ PVC pipe with a 1/2″ to 1″ PVC nozzle is filled with the stucco mix. The PVC pipe is tapped with a hammer to allow the stucco mix to flow into the bamboo cavity. The bamboo cavity is also tapped with a hammer to settle the stucco mix and assure a complete fill of the cavity.
These foundation sections have all been pre-fabricated off site. The octagon allows for eight equal sized foundation sections. The entire foundation for up to a 30 ft diameter octagon can be easily shipped in this way.
Sections of a cupola can also be prefabricated and shipped.
The site has been filled and eight corner post holes have been dug to original earth. Placement and alignment using this method was completed in a few hours.
Side beam sections using a ferrocement structure was stuccoed before placement.
The entire structure is tied together to a center post. In this design the few interior walls fall over these reinforced concrete subfloor structures.
As you can see, concrete was placed below the stuccoed wall beams to encase the lower rebar and prevent earth contact. When the floor is poured it will encase the rebar and make a unibody floor foundation system. Pouring the floor at the end offers several advantages. The roof can go up faster in the rainy season. Plumbing and electrical can go in at leisure and reduce errors in stubbing out thru a slab, increasing accuracy and efficiency.
Walls are pre-framed, in this case the window bars are installed and the windows will clip in and be secured later.
Assembly of roof is rapid. In the next house we will have a specially designed center post to make for quick alignment of exterior walls and assure absolute center of the cupola. This will also speed up assembly!
The center of the primary roof is ready to fill with stucco mix. The base of the cupola is installed.
Upper roof sections are layed out and fabricated prior to installation. All horizontal pieces are drilled with large diameter hole saws and use specially made drill guides we welded up for the purpose.
Each section is installed. There is room left between them on top to allow for electrical and plumbing vents, and it gives a wider look to the bamboo beam from below. These are later bolted and secured together using brackets. The final bottom piece is custom cut and fit last.
Here is a typical connection for the upper roof section.
Finished inside Cupola. This house has the white foam insulation as the ceiling. Future projects can choose between a flattened bamboo (seen under Affordable Kit Homes), sheetrock, wood, etc as a ceiling finish with the insulation and roofing on top.
A closer look at the wall lathing. This photo shows the back of the shower in what will be the water heater room. The shower is finished with ferrocement walls that are fully waterproof and ready for tile.
This is a very open “studio” floor plan. This is a center wall to support the cupola and provide a wall for electrical switches, plugs and lights. This wall can be extended in the future to separate the bedroom area from the salon, dining, and kitchen areas.
In the background you can see the adobe finish on the walls. This was supposed to be a clay based soil mixed with rice hulls and lime putty. Unfortunately no soil was locally available with clay, so we did the first coat with normal stucco. The second adobe coats used more lime, but, we got more cracking than usual. We may be doing a lime putty and sand plaster coat as a final finish. Other walls done in with good clay soils have turned out very successfully. Like all Adobe it tends to develop some cracks, and these can be quite decorative.
In future homes, most likely we will NOT be using the adobe finish, but the wall area in between the structural bamboo corners will be standard steel stud with sheet rock interior and fiber cement (Plycem) wood grained siding exterior.
Here is the finished inside walls and ceiling. Note the ventilation area around the top of each wall, this has insect screen, as does the cupola openings
This is the steel framing and lathing for the ferrocement cabinets in the kitchen. Front center is a dining table area. There is a cutout area for the stove and far right a refrigerator at the end of the cabinets.
Almost finished and ready for stucco and tile
Here is the garbage pile from this project.
The waste insulation and some waste roofing would fill a couple of 50 gallon drums. The waste bamboo is negligible. Low waste, efficient construction (low labor costs), low material costs (Use of low embodied energy materials) are the keys to affordable construction. The project is awaiting final finishes of tile, cabinets, plumbing and lighting. When the project is finished more pictures will be included.