Wood Fired Oven: Hearth

Forming up the hearth involved doing something I'd never done: Vermiculite concrete. This is a strange mixture to say the least. The base slab for the hearth was something very familiar to me. The texture and feel of the insulating concrete was not. It seemed that, as we mixed the vermiculite and cement mixture and added water, the thirsty vermiculite soaked all the water we threw at it. I was afraid of weakening the batches by making them too soupy. Yet, the 'oatmeal-like' consistency called for by the Forno Bravo (http://www.fornobravo.com/) wasn't the easiest thing to work with. We ended up adding a touch more water for workability (if that is a word).

Here's what makes me nervous. After three days, the insulating layer seemed to still be a bit on the soft side. It could be the water retention qualities of vermiculite...or the thickness of the entire lab curing ever so slowly. The consistency of the vermiculite portion of the slab is sort of like clay prior to being fired. Nonetheless, I was concerned that I screwed something up, although I have read in forums that the mix never hardens like normal concrete. I guess only time will tell. Ho bisogno di pazienza. Pazienza e una virtu. By the way, the picture on the right shows a bow in the slab...it must be an optical illusion from my phone's camera. Really...it can't be poor craftsmanship ;)

Afterglow from January 8th

I'm finally coming down from a massive sports high. My University of Florida Gators defeated Oklahoma in the BCS Football National Championship Game. I was extremely nervous about the outcome. I thought Oklahoma's offense would do some serious damage. But UF's defense kept making key plays and in the fourth quarter it was decided. What a relief.

All I can say is Go Gators!

Wood Fired Oven: Forming up the Hearth

Our next step is the hearth. The hearth is made up of two layers of concrete: one structural 3 1/2" slab with rebar and wire mesh and another on top made up of insulating concrete. This insulating concrete is made by mixing cement with vermiculite to make a fluffy lightweight concrete having insulating qualities. We'll try the pour this Saturday if the rain holds up.
To form the interior part of the stand we built braces to support the OSB deck. These are not fastened to the structure since the weight of the concrete will hold them in place. Look at the 2x4 cleat around the perimiter of the block stand. It is screwed into the block with TapCon screws and will support/line-up the 2x8 hearth forms.

A note about green building: We strive to use as much reclaimed/recycled materials in this project. My friend Ben has acquired the great majority of the lumber from construction site dumpsters (with the builder's permission). This included rebar, 2x4's, 2x8's, plywood. He could have enought to build an addition to my house, but he's too busy to scrounge all day for me! It's amazing how much builders waste in building homes. You would think that in a tight economy, they would revisit their building practices to conserve materials. We've saved quite a bit in material costs.
Next blog entry we will detail the pour. After the hearth comes the meat and potatoes of the build--the brick oven. Thanks to my brother-in-law Lance, I now have a brick cut schedule for each course of the dome. I wish I knew AutoCad. I am, though, working on Google SketchUp to mock up the look of the oven. We'll see how that turns out.

Wood Fired Oven: Building the stand

The next step after forming and pouring a foundation is the building of a block stand to raise and support the hearth. The block stand was built with standard 8x8x16 block. We used a dry stack method where the joints are not mortared but every other core hole is filled with concrete and rebar. It's easy for us non-mason folk.

We also were going to pour in place a lintel. But after much debate with my friends, we used angle iron instead. I figured, this is my first one, let's not complicate matters.

After the block cures we'll form and pour the hearth. It will have to be when I get back from a mini-vacation to Tennessee.

The hearth is composed of 3.5" of structural concrete and 4" of vermiculite concrete. Vermiculite is added to cement to make an insulation layer for the hearth. I scoured the city for vermiculite and couldn't find it readily. I had read that some folks found it at Home Depot. When I called my local HD, sure enough, I found they had 10 bags each at 4cu ft of medium grade horticultural vermiculite! The lady said the price was $12.95--incidentally much cheaper than any other place I found. But when I arrived there was another surprise...they had vermiculite on clearance at $9.00!

We'll see how well we frame up the forms for the hearth. So far...so good.

Building a wood-fired oven

So, my obsession with wood-fired ovens has spilled into action. I will begin to document my effort to create an italian domed wood fired oven. I found very specific plans/how-to doc at http://www.fornobravo.com/ . This site also contain a forum for past, current and would-be oven constructors.

The oven "look" I am aiming for is similar to the one shown in the picture here on the left.

The pompeii oven is a tried and true feat of efficient design and engineering. An oven constructed as prescribed in the how-to's can be very useful and life enhancing.

My version is a corner oven; a part of a larger outdoor living area project. Here in North Florida, living outdoors is very pleasurable except for the months of July-Aug-Sept where temperature/humidity combos are unpleasant.

I started on December 27, 2008 forming a base for the stand where the oven will sit. Note the necessary elements (beer, friends) to building the slab on the picture on right. Friends are necessary to bounce ideas and to check yourself. Beer just eases the pain of lifting 40-50 80lb bags of concrete mix.

The slab was built much like a monolithic slab where there is a footer around the perimiter. My thought was that since the majority of the weight pressure falls on the perimiter of the slab, a deeper reinforced footer would better sustain the construct--specially here in Florida where the soil is sandy. The footer (around 13/14" finished depth) contains 1/2" rebar which connects to the main slab. The main area has wire mesh and rebar and is poured at 4/5" in depth. We'll see if I have screwed it all up.

Here's a picture of the finished stand foundation. We're set to run block on it on 1/10/09. Hope I can keep the momentum going!

Camping the new year

Nothing says escape like an outdoor camping adventure. Escape from what? Did you go anywhere near a mall or major store this crazed holiday season? It seems as if it unofficially begins in the days after Halloween and goes non-stop until after the new year. I believe next year the season will begin after July 4th. Mark my words.

We took some days to enjoy the beauty of nature, specially here in Northeast Florida where we live. We set up camp in Little Talbot Island State Park. It is on one of the many barrier islands that begin in Florida and dot the eastern seaboard of North America. If you live anywhere near North Florida, it is worth the time to visit and enjoy the Talbots Park System. The campsite at Little Talbot Island is located on the Myrtle Creek side of the island (west). The beach side has basic facilities for visiting/picnicking yet remains mostly unspoiled by man. Believe me when I say it is "wild". There are many wild animals that curiously look upon us as invaders in their territory.

We camped in our roomy tent. We enjoy the tent very much. The only disadvantage is the inability to keep noise (not nature but neighbors) out of the tent while attempting to sleep.

Nonetheless, it was a very enjoyable time. Isa spent almost the entire time riding her bike. Meanwhile, the parents veg'd. I spent a lot of time cooking on the fire pit. I felt like a nomad.

Good times. Good times.

This is what life is supposed to be like.