Thursday, July 8, 2010
Setting wall forms
Just as we did at Terra's house, we're using the Atlas form system to build Jack's walls. The system is comprised of 7" wide aluminum beams for walers and 7-1/2" wide aluminum strongback to support the walers. The form facing itself is 3/4" HDO plywood (HDO for high-density overlay). You pre-assemble the panels in selected lengths, then use a grade-all or small boom truck to set the panels.
This system is in stark contrast to the original California form (see The Rammed Earth House) in that you spend several days setting large wall sections rather than a few hours setting forms for individual panels. Each system has its advantages and its disadvantages. The Atlas system allows for ramming long, continuous walls, but it requires a big investment in forming materials. The California system keeps forming materials to a minimum, but results in vertical seams every six or eight feet.
Edward, Rigo, and Nick spent about a week assembling the 16 panels we needed for Jack's 20' x 24' modules. We bought a unit (44 pieces) of new 4' x 10' sheets of HDO plywood for the wall forms. Per sheet price from Golden State Lumber was around $94.00. We own the aluma beams and the strongbacks.
Yesterday, after we stripped the foundation forms and backfilled, we set the three door displacement boxes, then set three of the form panels using a rented Grade-all with a boom mast. We resumed setting panels this morning and finished about 12:30. We plumbed all the panels, screwed the outside corners together, knitted the seams with 2 x 6's and wedges, and screwed spreaders across the top to set the 18" spacing. The photos below show the process. If anyone wants more information on the Atlas system, including photos of how we used these same forms in 300 foot lengths to build the Disney Child Care Center, drop me a line at Rammed Earth Works and I'll respond.