Building a wood-fired oven, part 1

Here, finally, is the first oven-building update.  We have some plans, we have some clay, and we have a hole in the ground.

The plans aren’t perfect–the hearth, for example, needs to be level with the top of the foundation–but I feel comfortable that we’ve thought as much as we can about the design.  Our plans are the result of oven visits, lots of reading, consulting with the brick-oven yahoo group, and conversations with Felix Addison and Kiko Denzer.  And I expect they will continue to change as we start the build!  If you would like to have a closer look at our plans, contact us and we’ll send you a copy.  And we welcome any feedback you may have!

We are going with a 4.5′ by 5.5′ egg-shaped hearth and a seven inch thick clay dome in the Quebecois style.  I like this style because the entire oven interior is rounded, which should help prevent eddies (read: cold spots).  Also, the highest, widest point of the oven is in the back, with the dome sloping down- and inward towards the door.  This will (hopefully) help support the dome at its widest point and encourage the heat to circulate fully through the oven before it exits the chimney, which is right in front of the door, making the oven more efficient. The oven dome will be insulated with twelve inches of sawdust held together with clay slip, while the firebrick hearth and clay subfloor will be insulated with a foot of beer bottles–of which we have a lot–embedded in the same clay-sawdust mixture.

The clay is a grey marine clay that contains quite a lot of white silt.  Ben found the clay at a nearby building site, where it is being excavated for a foundation.  We’ve tested the clay on some bricks, and a 1:1 mixture of clay and masonry sand seems to give us the best compromise between strength and shrinkage.  The next step is to use it to try to build a quick little oven like the ones Kiko describes in his book, also known as our oven bible.

So with plans in hand we have started the foundation.  We finished excavating and tamping down the 18-inch-deep hole in the ground on Christmas Eve.  Most of the rocks in the top 8 inches or so.  Its tempting to speculate that they came down the mountain with the 1969 mudslide that covered the property.

3 thoughts on “Building a wood-fired oven, part 1

  1. cindyjackson

    The third graders at Charlottesville Waldorf School are baking in the Cobb oven they built this fall for the third time today. E-mail me if you’d like to see photos of them working.

  2. Pingback: Clay Oven Construction and Deconstruction, Part 3 | Little Hat Creek Farm

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