This is the technique used by Cato on the health clinic in Chiapas, Mexico, and can be visualized more accurately be referring to this PDF file.
“Here is an idea that may help other builders to stay on level while laying the bags. At first, after laying and tamping every row, we checked if we were on level using a water hose level. Like the guy with the beautiful house in Belize (Jesse Loving), we used blocks as window and door forms. We figured we could also use one of these blocks as a “stopper” at the ends of bags. It helped in different ways. We had teams of two people laying bags. While tamping, one guy was standing on the previous tamped bag, while the other person could stand on the “stopper”, thus avoiding having to stand on the barbed wire. (It took a little practice and concentration, but it was safe.) The “stopper” (large block) also helped to square the ends of bags. The blocks are 40 cm X 20 cm X 15 cm. Each bag was tamped the same thickness as the bags. Thus, we managed to have constant 15 cm thick rows. With this trick, we managed to stay under 1 or 2 cm level tolerance. We are talking about 71 bags per row (lower rows), or 56 bags per row (higher rows) and a distance of about 12 meters from side to side.
Anyway, we decided we could go a little faster if we checked level every two rows. We had the same results. 1-2 cm tolerance. So we did it every three rows with the same results. (Yes, we double checked with a water hose level). I must add that we put good care on our moist dirt mix.
I hope this helps somehow. In my understanding of your blog, every little contribution to improve the way we construct things, and the spirit of cooperation are little steps towards better, safer, affordable housing.”
I love the plumb walls! This is really nice! Im working on a foundation for a shed right now and figured that I didnt have to be anal about the rows being level as long as I end up with a cement bond beam and use that to make the walls level. I had intended on divoting the bags as I work up the wall, but now am also going to tamp the sides. Will this create a straight wall? I like the cement blocks and think I have some around to use for the openings to help stay on the straight and narrow
I think Kelly is going to update this blog post now that we have some photos from Cato that will help illustrate the process.
It’s best to keep every course level, starting from the foundation courses.
Tamping the sides 1. eliminates big bulges, 2. aligns the wall, 3. greatly reduces plaster work.