Tuesday, 10 August 2010

Phase 1 - Build the Wood Bunker

1. Foundations and first courses
After measuring the plot, I dug 6" deep foundations a little wider than two-brick's width and filled them with concrete.

Once dry, I laid two courses only where they would be visible, and allowed just a single course for the proposed arched entrance to the bunker. For the far side and back I choose to opt for breeze block straight on to the foundation, so save money.

2. The walls
I choose to breeze block and render the walls for economy, simplicity and speed.

Notice, the notches I cut out of the end walls to sit the concrete lintels in. Working with, cutting and shaping the breeze blocks was, as they say, a breeze!

3. Lintel supports for bunker roof/oven floor
After then deciding to build two further posts for each lintel, I cemented them in.

I gave it a good few days to dry out, then added the brick arch* and bunker roof/oven floor by laying the concrete slabs. The observant among you will spot the 'deliberate mistake' - I miscalculated the length of the slabs and came up short, so had to finished the very end with breeze blocks - no big deal!

* The build the brick arch I simply cut two bit of wood the the shape I wanted the opening to be. Nailed them together. Placed this on two thin sticks to raise it slightly. Laid the brick arch and remaining wall blocks on top. Let it to dry, then kicked out the brick arch. Voila!

4. The insulated oven sub-floor
As guided by the book Build Your Own Earth Oven by Kiko Denzer and Hannah Field, I had to now make an insulated, structurally sound sub-floor for the oven. After building the edge with more breeze blocks the inside was filled with a combination of clay, sawdust and empty wine and beer bottles. The liver took quite a bashing the night before to empty all of these, I can tell you!

As I still wasn't 100% confident about using only clay (and contrary to the books guidelines), I added a little bit of cement to the insulation mix - but I know now that this really isn't necessary.

5. Render face of breeze blocks

This was the only thing I felt I'd have trouble with, so I enlisted my father-in-law Mick. This was definitely the right thing to do. In the time it took me to render on quarter of the back, he had done all the front and used about a sixth of the materials I had used. I was quite happy at that point to sit back and watch a master at work.

Think the render mix was 5 sand to 1 cement. Each face was battoned first with 2x1" wood before having 2 coats of the render mix applied. Once complete, the finished faces were battoned for the remaining faces to be rendered in the same way.

And that was basically the Wood Bunker FINISHED !!