Approximately forty-five pieces of Bamboo, three Meters long (10') have been used to make these wall frames. The example is 8.4 M2 of floor area; 135 M of bamboo Ö 8.4 M2 = 16 meters of bamboo per square Meter of floor area. The equivalent figure in feet is 450' of bamboo Ö 90.4 ft2 of floor area = 5' of bamboo per square foot of floor area.
These are trusses from earlier explorations, construction photos have been published in greater detail in the ferrocement.com manual series, or in various sections of this website, see welcome page listing. The larger size truss spans four Meters, these trusses were a prior test, made several years ago from bamboo removed from an even older test. The example shelter is sized to fit the existing trusses, allowing a 25 cm overhang (± 10").
The larger truss joints were made burrito style, a burlap wrap sandwiches a filling of hemp or flax fiber. The smaller truss, two Meters, is bound with utility muslin soaked in a binder and wrapped around the bamboo, like a bandage. Wrap joints cost between 2 and 5 cents each and are superior to the the burrito style, both may be fabricated using various binders. Cure time ranges from 1/2 hr, for modern exotics, to three or four days before preliminary, gentle construction positioning and assembly are possible, using standard cement and acrylic as the binder, Space-age mud and wattle. Standard construction grade cement slurry will also work, remembering that 28 moist days is the ideal cure time for common high quality construction cement, medium warm weather.
The structure is a rectangle when the diagonal measurements are equal (corner to corner). Pythagorean Theorem; a2 + b2 = c2.
Vertical poles temporarily lashed to the wall segments hold the first truss in place. Use of temporary tape wraps and small size causes construction order for this example to occasionally be a little out of order; for example, walls would already be cured space-age mud and wattle wraps, like the trusses, before standing up for assembly.
The ridge pole is placed as soon as the second truss is attached. It is reasonable to make the end walls as one piece and then fill in the remaining roof area central trusses. If more than one structure with end walls of a chosen design are to be built, and this were the model of it, then one of these end walls could be used to make a jig to produce the wall frames.
There is no need for the ridge to be straight, it could be curved downward in the center to create a catenary curve with upturned ends similar to architecture from Thailand. Such an architectural detail would require trusses of different heights that are made to fit along the curved ridge. This would be a simple design option to accomplish.
Although sixty centimeter spacing for the trusses provides sufficient work area when standing on a ladder between them (24"), the vertical wall poles are too widly spaced for this builder's eye.
Continue roof frame assembly