Week 12. The roof construction process is complete. 1. Trusses installed. 2. Ridge and minor beams installed. 3. Caibros/Rafters installed at 60cm on center. 4. Ripoa/Battons installed at 34cm on center to correspond to roof tile dimensions.
Monday, October 4, 2010
Week 11. The main project of week eleven is the construction of the roof system. Also, as pictured in the top right, the floor is tamped down in preparation for a slab which is one of the last components (due in part because it is colored concrete). Also shown above (bottom right) is a scaffolding system and (bottom left) the roof monitor.
The installation of the truss is a muli step process where as each truss is set upside down on the bond beam and turned up individually using long sticks. The sticks are used as braces to temporarily hole the trusses upright. A long stick (rat run) is placed on the collar tie of each truss to stabilize the bottom and an angle brace is installed to keep it upright. On center dimensions are measure out on the rat run and the truss is plumbed up with the brace. This is a temporary measure until the ridge beam is installed. The rat run also acts as scaffolding in this scenario.
Hardware is strategically used. In the truss it is located at all joints and to hold down the viga/beam cleat (left). Straps are used at the shiplap of viga/beams that break off of the structural trusses and columns (top right). Rebar that is extended past the beam is bent over to tie it down to the column (Bottom Right).
Door and window rough openings are oversized to accommodate nails that are situated prior to installation of the jamb. Once all the jambs are set (bottom, then top, then sides or as a framed unit) the gap is filled with mortar (massa) which consumes the nails and secures the wood in place.
The wall finish is a 2 to 3 step process. Much like cementatious applications in the U.S. (as opposed to synthetic) it is a three step process in most cases. Above we see the chapisco (scratch coat) method where the looser mixture is flung against the wall to create a rough surface for bonding. This is sometimes done by flinging the mixture through a screen 2cm x 2cm grid. The second coat emboco is much like a brown coat and the third is the finish, reboco.
The bio sand filter has been tested and works properly. One of the solar panels mocked up and tested. They will ultimately be situated on the roof with the angle of the roof being designed to the optimal specs for solar orientation.
Week 9: This week interior and exterior walls block-work are completed (for the most part), four structural trusses are fabricated, and the bond beam formwork is installed and ready for concrete. It is also James' last week on site, leaving John, Ethan, Giorie, Julie, Joao, and Eder. A cold streak has subsided at least for now.
The bond beam formwork is made up of the column formwork that was salvageable. A streak of cold and cloudy weather made it so more formwork could be reused. The blistering sun often saps the moisture from the wood causing cracks and splits that compromise the integrity of the formwork. (Note) On the same note during the hot and sunny days, when formwork is dismantled it is beneficial to wet the exposed concrete a few times a day for a few days so the moisture is retained at a pace that increases the strength of the concrete. Formwork joints are staggered from exterior to interior and a gusset is installed at each joint.
The thickness of the bond beam is consistent with the column at 15cm. The wall thickness is 9cm. Therefore the 6cm caibro (wood member) will suffice in padding out for the void that is created. It is screwed to the bottom of the formwork on the interior side of the wall. 4/2 rebar is drilled through the formwork and bent over on each side to prevent a lateral blowout. Additional cross members are screwed to the top and wire is wrapped completely around the formwork. All formwork is flushed to the top and leveled from the top to ensure that the trusses and roof system plane out properly. Shown above is the bond beam and metal retention members being bent with a pipe found on site.
Trusses are completed and await metal hardware that are applied at all the joints for additional support. Pictured above (top) are the millwork (our lumberjack-left) and fabricator (right). Trusses will be installed after the bond beam is poured and given time to set properly.
Mercedes, Giorie, Pedreiro, and Servante worked on building up and weaving the walls while John, Ethan, and Julie installed the bond beam cages and James completed the fabrication of the structural trusses. Walls that meet at corner or "T" conditions are woven together whereas every other course block laps the previous block perpendicularly. Masons line and the plumb bob are the tools of choice for level and plumb and squaring the space is a matter of keeping an eye on the diagonal dimensions of the space.
Plumbing supplies and other hardware arrived on site which made it a bit easier to understand the wastewater and delivery connections, dimensions, and placement of stub-outs and the larger gravity feed water systems. Much like North American coding it is done by color where brown pipe is used in exterior conditions and white in interior.