web analytics
Vermiculite Concrete hearth insulation - Forno Bravo Forum: The Wood-Fired Oven Community



Forno Bravo Forum Thread Message

Hello, Forno Bravo Community Forum Members!

The Forno Bravo team has heard the feedback in regards to the community forum. We wanted to take the time to re-enforce our commitment to a fully engaged Forum with professional moderation.

Our top priority as a company is to fix all forum errors and issues that you are experiencing. As we are swiftly working on these problems, we want to say that we highly value the Forum Bravo Community Forum and every single community forum member.

We have set up this thread so that every member can address any concerns, issues and questions about the forum. Please feel free to ask whatever you would like in regards to the forum; let us know what issues you are experiencing so we can work on resolving them as fast as possible. However, we stress that we would like constructive engagement, so please be specific about the issue you are experiencing.

Thank you for all of your patience and continued support.

Link to topic: http://www.fornobravo.com/community/...with-new-forum
See more
See less

Vermiculite Concrete hearth insulation

  • Filter
  • Time
  • Show
Clear All
new posts

  • Vermiculite Concrete hearth insulation

    Iím going to pour my vermiculite concrete layer this weekend. I poured test sample of the vermiculite and noticed areas of small air pockets. Should I be concerned with moisture or air pocket in the bottom insulation layer that may expand later when heat is applied? Perhaps it is assumed that hot air and steam slowly works its way out thru the brick floor and is not a problem.

  • #2
    Re: Vermiculite Concrete hearth insulation

    Air pockets are the point of vermiculite concrete. It's the air trapped in the layer that insulates. You're good to go.
    My geodesic oven project: part 1, part 2


    • #3
      Re: Vermiculite Concrete hearth insulation

      Exactly...the air pockets are your friend. However, I would pat the wet mixture down lightly when you pour it and level it...tiny airpockets is the idea, big caves of air probably not so great.
      Check out my oven progress here: http://www.fornobravo.com/forum/phot...dex.php?u=4147

      See ALL of my pictures here:


      • #4
        Re: Vermiculite Concrete hearth insulation

        Something I noticed when I was stuccoing my oven- in the front, where my vermicrete had slumped a little and was a tad thick, I took a brick and "sanded" it a little to get it flat. I noticed that the newly exposed inside was much softer and crumblier than the outside. Sort of like when you make a sand castle and it dries on the outside, and when you mess with it, it all slides out. When I applied the vermicrete to the exterior of the landing and vent, I patted it into position. Did this bring the portland to the surface more, sort of making a shell around the vermiculite?

        I just covered the spot up with stucco as I had intended, but if I hadn't meant to do that, I would have had a problem, since it was a vertical surface. If it had been a horizontal one, I don't think it would have mattered. I have the same vermicrete under the oven and the insulating board, and it's never shifted or compacted in any way. But I didn't apply it the same way, either. It was mixed and dumped into the form, screeded flat, and left alone.

        Just wondering if the way you apply the vermicrete changes the insulating value and/or the structural integrity. Obviously, the layer around the oven doesn't need the same strength as the layer under it.



        • #5
          Re: Vermiculite Concrete hearth insulation

          Thanks for the input. I will pour my vermiculite with confidence and my pizza will taste great.
          I have posted a picture of my test pour (broken to see the inside). It is a very interesting medium to work with. Also, I found that mixing the dry vermiculite & cement, (5:1 ratio, each part being 2.5 quarts) in a 5 gallon bucket with lid works well. Tumble for a few minutes then I am then transferring it into other buckets until I have enough to mix with water and fill my form.
          PhotoPlog - Hearth and Stand