Applying adobe to a wall construction
Photo by Tom Keeling
In this short video I go through the different ways you can test your the adobe patches that we rendered in a previous post.
You are really going to be trying your hardest to remove the patches from the wall and damage them. You want to know if they are going to be easily damaged by a falling cupboard or by water bring spilled on them. You want to know if there is so much sand in the mix that it easily brushes off and may make a mess on the floor in future. You will also need to know if there is too much clay in the mix which could have made it crack too much as it dried.
For final layers you will also be looking at finished color and smoothness perhaps.
To simulate a chair knocking against the wall I hit it hard with a hammer and it held up really well with very little impact marks. If the hammer created a lot of damage you may think about adding more sand as this is where the strength lies in this respect.
I also used the sharp side of the hammer to try to take chunks of the patch off the wall which I couldn't so that was a great result. If pieces of the render came off then you may look at the clay content, or the preparation you did to the wall beforehand...was it clean? was it too dry when you applied? or too wet? did you use enough clay slip before applying the render?
You can then pass your hand over the render to see how it feels to the touch. For a final render this will be important for aesthetic reasons but for this layer which was before the final thin layer the reason was to see if too much sand dusted off. A little is ok but too much may compromise the following layer.
To review the clay content you want to look for cracks. Earthen finishes often have small cracks and that isn't a problem. We were lucky in that only one mix had cracks so we discarded that mix. If they all had cracks then you may want to go for the one with the smallest. Very fine cracks can always be compressed and closed as the render dries.
Tom Keelingis based in Portugal and has traveled throughout Brazil and Eastern Europe learning about natural building and farming. He’s working on a two-story stone barn renovation using clay and wood, and including a shower and toilet block built using rammed earth and adobe bricks. Connect with Tom at Fazenda Tomati and on Facebook and Instagram. Read all of his MOTHER EARTH NEWS posts here.
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