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oven floor - Forno Bravo Forum: The Wood-Fired Oven Community



I'm Peter Reinhart! Ask Me Anything! Monday, February 15, 2016 7:00-8:00 pm EST

To kick off our AMA feature, we have invited author, chef and master bread maker and host of Pizza Quest, Peter Reinhart, to be our first host! Peter will be in the Forum on Monday, February 15th, from 7:00 - 8:00 pm EST. If you are unable to be online during the live session, you can post your questions in the sticky post. Peter will answer those questions during the live session on February 15th. You can view Peter's answers to your questions as well as what happened during the live session in the session thread.

Ask Me Anything New Forum Feature

You will notice a new forum at the top of the main page called, "Ask Me Anything". This forum will be used for live one hour "Ask Me Anything" (AMA) sessions hosted by people who are knowledgeable in different areas pertaining to wood fired ovens. How it works:
- Each AMA will have a "sticky" thread where the community can post questions they would like answered during the live session. This will allow everyone to participate even if you can't be online for the live session. These questions will not be answered by the host until the live AMA; if you need an answer quickly, you should post it in the appropriate Forum area for the community to respond.
- Another thread will be posted for the live AMA. Registered users who are logged in during the live session can interact with the host by asking questions and receiving responses.
- The live thread will remain in the AMA forum to view after the session.

We hope you enjoy this new feature! Please let us know if there is a topic that you'd like to have as an AMA and we'll look for a host!

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  • oven floor

    This is my first post and am new to the forum and wood burning ovens. Ive recently built a 36 inch , which i built from this site . My goal was to build it with local products (on budget). I live in South Africa. I have 50 mm vermiculite under a 60mm clay paver. The dome is built with solid old clay bricks and ive used a crusher cement mix for the mortar(given to me by a local who assured me is fire proof). The dome is covered with a 25mm blanket and about 80mm of vermiculite. Ive then plastered a waterproof plaster over.

    My problem is the floor doesnt get hot enough for pizza. With a big fire the dome gets over 950f and the cooking floor max at about 550f even with the flames lapping over. After 1 or 2 pizza it drops quickly.

    Do u think the clay floor is the problem or has anyone got any sugestions?
    Does the oven get hotter with age?

  • #2

    How many fires have you had that brought the dome temperature to 950 F?

    Many times, the oven floor does not get up to pizza temperature because of trapped moisture (in the floor and vermicrete). You could see the oven floor get hotter with each firing, your insulation sounds about right.
    Lee B.
    DFW area, Texas, USA

    If you are thinking about building a brick oven, my advice is Here.
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    I try to learn from my mistakes, and from yours when you give me a heads up.


    • #3
      Re: oven floor


      Your build sounds spot on. The question is how long is the fire? After a couple of hours the hearth should be pretty damn hot - not 550f. Has the dome got hot enough to clear the soot? Even in a perfect world, you need the floor to re-charge if you are cooking many pizza's.
      Check out my pictures here:

      If at first you don't succeed... Skydiving isn't for you.


      • #4
        Re: oven floor

        The oven has been fired about 6 times to clear the soot.Maybe you right it needs to get the moisture out.Im taking measurements after the oven has been heating for about 1hr.

        I normally make a big fire in middle then move it across to the side and more wood and have flames lapping over the dome.Then i take the temp. Hopefully im doing it right?


        • #5
          Re: oven floor

          Don't know how many fires you've had in it, but I think Lee is spot on, it sounds like your oven still has moisture under the floor. If you covered the vermicrete insulation under the floor as soon as it set, then you trap a huge amount of water under there (about a third of the total volume is water) and it's then hard to eliminate. I think it's best to leave it to the sun and wind for a couple of weeks (if possible) to do most of the job of eliminating the water. It takes many more fires than you would think to dry an oven out properly. My guess is that you will find the oven improves if you just keep firing it. Try this before you do anything drastic.
          50mm vermicrete on its own is a bit thin IMO what ratio of cement did you use? And did you add any sand to the mix. These will both reduce the value of the insulation.
          Last edited by david s; 05-11-2012, 06:36 AM.
          Kindled with zeal and fired with passion.


          • #6
            Re: oven floor

            I used 1bag of vermiculite to half a bag cement(50kg bag)>There was no sand added.


            • #7
              Re: oven floor

              Assuming the vermiculite is 100 litres then your mix is around 5:1 by volume. I think the normal requirement is around 100mm under floor insulation of 5:1 vermicrete. I still think you have moisture under there and the performance will improve with more firings.
              Kindled with zeal and fired with passion.


              • #8
                Re: oven floor

                "I normally make a big fire in middle then move it across to the side"

                Try leaving your fire in the middle until the wood burns down to coals and you are ready to cook. Then push it to the side or to the back.


                • #9
                  Re: oven floor

                  When I first started using wood fired ovens, I would push the coals to the side. Now I push them to the back. I find this seems to free up more cooking space and gives an element of heat control with the hotter area towards the fire and cooler towards the opening.

                  I generally find I can do all the cooking with the heat from the initial firing and do not add wood.