Description Of Wall
The Pumice wall system is made of sandbags filled with pumice. The Pumice wall construction is shown in Figures 1-3. The Pumice wall is constructed with filled bags which are 16 inches wide, 3 inches high and 2 feet long. Sand bags contain 2/3 cubic feet of pumice each. The open flap of the filled bag is 6 inches long and the bottom of the next bag sits on the 6 inch open flap of the previous bag. The masons level was used to control if the bags were flat and level. A layer of 4 sheets of newspaper was placed on top of every third layer of sandbags as requested by the wall designer. Three layers of sandbags were strapped together. This provided some stability by holding the bags to the plywood substrate which was used in place of adobe. Stucco is applied over the stucco lath. The stucco was pressed through the lath leaving no gaps between it and pumice layers.
Figure 1: Sand bags are filled with pumice
The stucco wall concept is believed to be applicable as a retrofit application in the southwest where adobe structure could be economically justified because of low labor costs. To conduct the
hot box test two layers of plywood were put up filling the entire hot box frame. A 2
× 4 wood framing was used on each side of the metering area to help support the pumice bags and to secure the 4
× 4 posts placed at each corner in real field applications.
Figure 2: The bags are stacked and tied together with plastic strapping in the wall.
Stucco netting was nailed to one end of the test wall and stretched horizontally across the length of the wall. The wire mesh was supported by the sandbags by tying plastic strapping around the sandbags to the wire mesh. Portland cement stucco, about 1- inch thick, was applied to the wire mesh to provide a solid weatherproof surface. On the second surface of Pumice wall, two layers of 7/16-in. plywood were installed.
Figure 3: Cement stucco is applied over the stucco lath. The stucco was pressed through the lath leaving no gaps between it and pumice layers.
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