Hello all first time posting. Long time DIYer first pizza oven build. We have been at it roughly 1 month now and will be setting the 3 base pieces for the Pizza oven this weekend. Very exciting.
I have included a few photos of the progress so far. I have a 2D rendering that i will include as soon as i update it with my recent changes.
The question I have is in regards to the stucco/mortar that is applied over the firebricks. for my design i will end up with a box over the top (Yes the 2D render would help with the vision) is there any reason why i should not or could not fill the void created in the corners with additional materials to help retain more heat? If not this area remains air void space.
After wrapping your oven with 2–3 layers of ceramic fiber blanket (and securing it firmly in place), you can fill the remaining void with vermiculite or perlite to boost insulation even further. Both are non-toxic, natural, affordable materials that help retain heat and protect the oven from outside temperature changes.
You can usually find 2 cubic foot bags at local nurseries or home/garden stores, or order from Uline (minimum of two bags — but you’ll likely use both). Most masonry or landscape supply stores carry vermiculite or perlite insulation in 4 cubic foot bags for around $15–$20, so it’s worth calling your local Masonry & Landscape Supply before ordering online.
Big box stores like Home Depot or Lowe’s sometimes stock large 4 cubic foot bags in the indoor plants section or near fertilizer and potting soil. If not, check your local plant nursery — just be sure they have the larger 2cf or 4cf bags (skip the small quart-sized ones).
If you can’t find it locally, Uline will ship (2) 4 cubic foot bags of Vermiculite / Grade 2 directly to your door within two days. You’ll have more than enough for your oven — and any leftover can be used for concrete block core insulation or sold on Craigslist or Facebook Marketplace.
So do you think it would have a similar advantage as buying an additional 6lb box of CFB and adding additional layers or do you think it would be more advantageous to do the additional layers of CFB before dumping the excess Perlite into the void?
If it won’t break the bank (many of our customers are on a strict budget), I recommend getting 2 boxes of blankets. That’s 100 square feet of blanket, which should allow for 3 to 3.5 layers (use the half layer on top of the oven) and 2 layers in front with 3 layers in the back. Then, secure the blanket tightly against the oven with chicken wire. After that, dump a few bags of Vermiculite or Perlite into the void. This setup would provide excellent insulation for anyone who wants to bake all weekend and still have a very warm oven on Monday morning.
I agree with @BrickWood’s excellent advice, and in this particular case I’d add that either Vermiculite or Perlite will serve equally well in this application because they’re being used dry. So you can splurge a bit on the CFB and then purchase whichever of those two materials that is less expensive.
For the wet-cast insulating layer in the oven slab, I’ve preferred Vermiculite because it sheds water and thus dries much more quickly than Perlite, which retains water and dries slowly. For dry-space applications, the consideration is material cost rather than curing time.
