Adding Hearth Insulation Layer

Above the layer of Rocks we added the bottom insulation layer which insulates the hearth (the oven floor) from the base of the oven.
We chose to make the insulation out of empty glass bottles set in a combination of grass clippings (which we collected from a large pile which remained from mowing a soccer field) with clay slip (clay mixed with water to make a clay 'soup').
The layer of insulation is 5 inches thick.
In the pictures can be seen: Grass clipping mixed with clay slip, and the finished insulation layer.

Filling Center With Rocks

We collected rocks and pieces of broken concrete from near our house and filled the middle of the concrete ring with them. We made sure the rocks weren't loose so they could support the weight of the rest of the oven which will be built upon them. These rocks also act as a capillary break, which prevent rainwater from reaching the oven from the wet ground bellow.

Sheet metal and wooden poles removed

Here's the final wall.

Now it's time to fill in that big gap in the middle to create a surface to build the oven on.

As you can see we're keeping the concrete moist with wet towels and plastic to allow it to cure completely. The weather here is so hot and windy that without such steps the concrete would dry out too quickly.

Those concrete blocks which have been lying around the garden for a long time and taking up space are the first bit of fill to go in there.

Wall completed!!

Finally after about three months of working on the wall every other Friday, We poured the last bit of concrete.

On the bottom is my younger brother Paz who also helped tremendously.

Boy, I'm sure no other part of this project will be as long and hard!

A little more than one course of stone left

About one and a half more courses of stone remaining.

As we went up we knocked long sticks of wood into the ground to allow newly arranged stones to lean on them. That way we could secure the stones by pushing small stones under them from behind to push them out towards the sticks.

The begining of a beatiful oven base wall!

And I'm mixing the first batch of concrete

Sheet metal boundary is ready!

We ended up mixing about 50 kgs. of portland cement with sand and gravel by hand (we have no quickcrete and the likes here) for the whole base wall. Unfortunately we hardly took any pictures of the building process until almost the completion of the wall.

The wall was faced with flint stone from around where we live. We did one course of stone at a time, arranging the stones in a circle with a space left between them and the sheet metal. The stones were held in place by their own weight and by securing them with little bits of stone under them. This wasn't at all easy due to the fact that they had all kinds of odd shapes.

Then concrete was poured in the space between the stones and the sheet metal and manually vibrated to allow it to reach between the stones.

My brother Hallel is preparing the sheet metal that will serve as the inner boundary for the base wall.

The sheet metal was and old road sign some one threw out. It has served quite well for all kinds of projects involving pouring concrete in our garden.

Before setting up the sheet metal we dug about 10 cms. in the earth to enable the first bit of concrete to be poured in the created trench.