I would think that the ideas of building walls from found objects must have come seeing the work of Gaudi but it made real sense because I'd spent a large part of the 80's being a landscaper especially within what might be called hard landscaping. Even when I started basically laying cobblestones I became the one who cut them and later when they need to be fixed in cement, whether concrete or mortar, I was the one chosen. I'd done lot's of drawing as a kid and young adult so anything to do with lines, straight and curved, I was good at.
Towards the end of my one year at Art school a friend and I rented a space, a basement, right next door to where sky city was eventually built and pretty much straight away we started scouring back allies and skips for broken bricks and various detritus we could use to help us create the space we wanted in that basement. I taught this friend of mine how to mix a good mortar and how the basic elements worked and was quite amazed how quickly he took off with it.
Way back then was when I first realised this way of working could be taught to anyone as it's really just like playing with sand on the beach except it stays the way you make it... for a very long time.
So over the years I've pushed it quite a ways to see how things work and especially doing this kind of wall building without steel to realise how it can potentially crack up, which it has here and there, but I've learnt why and so I now have a fair idea of how this particular way of building can be used in all kinds of ways.
One of the things that has really appealed to me as an artist is being able to recycle bits and pieces especially in the sense of re-orientating how we look at rubbish because I really do think that most of it is useful in some way and that if we can start using it in ways which make it look good then this may very well raise what may the most important issue of seeing that alot of stuff will become rubbish and in doing so design it the first place not only for it's intended use but also with the idea in mind that after that use by date it can actually still have a use.
But first things first of course and this type of wall building using a sand and cement mix is basically about being able to glue together various already quite substantive rubbish as in glass bottles and jars, broken bricks and blocks, rocks, etc, as well as various steel and metal objects like old car parts. And because of the nature of the mortar, sand and cement mix, being pliable and then setting over a few days, the technique lends itself well to group activity just like a bunch of children playing in a sandbox.
The basic way to do this type of work is to have foundations laid with concrete and steel with a vertical steel every metre or so up about 600mm, just like a block wall, allowing each person involved about a metre each. Then you stagger off the people at 500mm intervals so they have a space to themselves and can work basically unhindered by what the person alongside them is doing and then the next day move along one or two sections, just like laying blocks again, so then each person fills between what two others did or builds on top of what others did. This takes for granted that the piles of things that will be put into the wall are piled ready for use with possibly a few personal piles alongside the community pile. Therefore I'd reckon about 8 people would be just about right because you'd get either one 8 mtr wall, two 4 mtrs ones or possibly even a 2x2 set of walls for a small building.