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Natural Building & appropriate technology’s blog 12

Article 12 of Natural Bldg and Appropriate Tech Internship 

Time for the bond beam! A team went to the workshop to set up the stirrups on the metal work and bring the rebar up to the place where we are building the sleep-outs.


Here we can see how the rebar fits into the stirrups.


The happy team moving the rebar.

Yesterday we lift up the height of our floor to be higher and for the moisture not to come into our floor. We are going to lay a layer of plastic on top of it and we don’t want to have hole into the plastic so we had to put a fine layer of sand to protect the plastic. And this layer also needs to be level. At this time of the process we didn’t have a dumpy level or laser level. What did we use? A long and straight piece of wood with a classic level on top of it and it works fine.


Big Ben and Rafa levelling the sand. We end up quite close.

To put in place the bond beam we have to create a “box” out of wood, which is going to include our steel bars coming out of our foundation. In this box we will pour concrete that will sit around the rebar. It creates the bond beam. The rebar is there to add some tensile strength, important in a place like New Zealand with earthquakes.


Tom cutting some wood to create the box.

The mix of concrete, one part cement for five parts aggregate (a mix of different sand and variable size gravels) and some water has to sit in the box. It means that the box needs to be level for the concrete to settle correctly. To do this we found out an old-fashioned but not less efficient dumpy level. I really appreciate working with this kind of tool. Good engineering, no electricity, efficient and two persons are needed. One thing that I have noticed today is that my skills are improving. The simple fact of putting a nail in a board, the nail goes fast and straight, the fear of hammering my finger has disappeared. Same things with the saw. With the help of Big Ben who taught me well I saw faster and straighter, which is not always this evident.


Checking the level of the profile and the box.


Setting up two board to create our box.


Here we can see the width of our box, it includes two steel bars coming out of the ground and the rebar will settle in.

And finally at the end of the day the truck with all the material for the concrete arrived and we are ready for tomorrow!


Cement and gravels.
Over and Out

 ~Oscar Morand, 7 March 2013, Natural Building and Appropriate Technology Intern

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