The first layer
Now we get to the exciting bit! You’ll need to mix four batches of clay-sand adobe (a batch is 1 builders bucket of clay and 2 builders buckets of sand). See how here. Give yourself plenty of time to finish this stage in one shot!Our oven is going to be just over 120cm in diameter at the base to fit our plinth nicely. That makes the internal diameter of the first layer at 80cm. Draw an 80cm diameter circle in the middle of the bricks.
If school maths was not your strong point…
- Draw two diagonal lines from corner to corner with a pencil. The x in the middle is the centre point
- Now make a loop of string that is 40cm long. Using a finger on the mid point at one en of the loop and a pencil at the other, draw a circle holding the loop taut. Voila a 80cm diameter circle (ish!)
Now you can make the sand former 80cm in diameter at the bottom and 40cm high- it’ll take about 5 bags of sand. Keep standing above it and look down to make it nice and dome shaped. Pat it and shape it as you go – all those sandcastles at the beach will have been good practice!
The next step is to drape wet newspaper over the dome, to stop the sand sticking to the adobe mix. This is a bit fiddly, but thankfully wet newspaper sticks to itself!The technique for building is to take a lump of the slay-sand mix and press it against the dome. With one hand flat against it presing it towards the dome, use a karate chop motion to make a wedge shape brick that slopes in. We are looking for a 7cm wide brick. a piece of wood marked up makes a good guide. Keep working round and then do the next layer. I found that you really need to work each brick in against the last one and, from the second layer, the ones unerneath to make sure there is no air bubbles or potential cracks. then finish the brick with the karate chop motion! You will soon get the hang of it and it’s a lot of fun. keep checking they are 7cm wide from the dome to! the base may widen out from the weight above it.
Leave it to dry!
Next Step – cutting the doorway