No announcement yet.

Insulation and ISTRA40 Mortar Mix questions - South Australia

  • Filter
  • Time
  • Show
Clear All
new posts

  • Insulation and ISTRA40 Mortar Mix questions - South Australia


    I am based in South Australia. I am about to start my dome build. I plan on using firebricks for the oven floor and clay pavers (230 by 114 by 70 from LittleHampton Bricks and Pavers) for the Dome.

    Just wondering if anyone can help with a couple of questions.

    1) I poured/layed 120mm of 5:1 vermicrete on top of the reinforced concrete top about a week ago. It is slowly curing. From what I have read this should be sufficient for insulation under the floow however after reading a few threads by some advocating CalSil board on top of the vermicrete I am starting to doubt myself. Do you think the vermicrete is enough or should I add 25mm of CalSil board on top as well?

    2) Regarding the mortar mix - I was thinking of using ISTRA 40. ISTRA40 is a high temperature calcium aluminate cement. I have used this in the past to construct a brick charcoal grill and it worked well and set extremely hard (although it goes off quite quickly so small batches at a time). I used a ratio (weight) of 4:1:0.4 of dry washed sand:ISTRA40: water in the past as recommended by Bianco and Adelaide Brighton Cement. I called ABC the other day and confirmed this mix for pizza oven construction and they agreed it was appropriate. Has anybody in Australia had any experience with this product? Does my proposal sound reasonable? Forno bravo recommend a different mix with the Calcium Aluminate cement and also recommend adding fireclay.