web analytics
Air as insulation - Forno Bravo Forum: The Wood-Fired Oven Community



New Forno Bravo Forum Feature

Forno Bravo Forum Community,

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.

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.

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!

Forno Bravo
See more
See less

Air as insulation

  • Filter
  • Time
  • Show
Clear All
new posts

  • Air as insulation

    HeIlo, I want to build a pizza oven at home, and I'm trying too too cut the cost since I will use it 1 3 per month.
    I know from house construction that a layer of air is one of the best insulation. I am wondering if I would built a layer of about 2-3" of air beneth the brick floor would be good instead of vermiculite concrete.
    The bricks would be layed on a metal plate and that on some supports to make the layer.
    Has anyone tried or researched this?

  • #2
    Re: Air as insulation

    Ive been wondering that same thing....I have seen some folks create an insulating slab by using a layer wine bottles laid into concrete. The wine bottles would give you nice structural integrity to the slab to support the weight of the firebrick....


    • #3
      Re: Air as insulation

      Small layers of air will heat rapidly and large ones will begin to convect. The best way to use air as insulation is to encapsulate it into ass many small pockets as possible. Perlite is cheap, cheaper than the metal you talked about would be by a factor of two or three times.


      • #4
        Re: Air as insulation

        steel is also a much better conductor of heat than the floor bricks so it will draw heat away from them, simply heating your insulation space. It is also prone to corrosion from heat/moisture.
        Kindled with zeal and fired with passion.


        • #5
          Re: Air as insulation

          Thank you for the replies
          This was a cheap solution because I would have used only very thin a metal sheet with supports. But in has some flaws as mentioned, like corrosion and heat conductivity.
          Or could I use rigid mineral wool blanket?
          There are talks about using this instead of refractory insulation, but it burns the organic parts from it and releases a smell. But the smell would be only the first and maybe the second time I would fire up the oven not all the time I think.
          If no then it looks like I have no choice but to use perlite/vermiculite concrete.
          Here in my country alot if not all wood ovens are done using a layer of broken glass, but I don't think this is good enough.


          • #6
            Re: Air as insulation

            Don't use standard Rockwool, it'll just turn to dust in no time!
            Not much good, when your whole oven is supported on it!

            Thermolite, or expanded cement blocks of any type will do well.


            • #7
              Re: Air as insulation

              Leca? I've actually been wondering the same thing, wouldn't something like the H+H aircrete block be good for the base of the oven? Being that the foam glass can be pretty hard to come by in some areas (Denmark for one)


              It also has some other nice qualities for the oven construction:

              Strong - you can build your oven 4 storeys tall
              Airtightness - Underwater oven anyone?
              Sound insulation - Quiet down that ROARING fire
              Fireproof - Well... Duh!
              Durable - Water resistant, frost resistant
              Excellent ballistic impact performance - probably most useful in Texas
              Build quality - Made to tight tolerances... Yea precision oven it is!

              From my personal experience I found it to be easy to work with, you can shape it with a normal saw and sand it level if you need to.

              With an isolation factor of : 0.15 W/mK it seems to me that it should serve well?

              Isolation values keep being a mystery to me but I've found these:
              Concrete: 1.40
              Vermiculite: 0.65
              Rockwool loose: 0.11
              Source: W/mK values

              Any thoughts on this?