Biscotto floor

[Ganlet]

I'm planning to use biscotto floor in my future WFO (36" low dome, main use neapolitan pizzas), and have luckily found a local supplier of "Biscotto di Sorrento". Have few concerns I would like to get answered first.

• The floor pieces are 40mm (1.57") thick - Is enough thermal mass?
  For domestic use, 1-2 pizzas at the time. Might perhaps put 10-24 mm (0.4-0.95") sand/ash/salt below if that makes any difference.
• I've heard these are quite fragile - Is it possible to cut the pices with an angle grinder without too much problems?
  Square to quarter circles pieces.

I'm also thinking about making 50/50 floor biscotto and high duty fire bricks. For two reasons, to mainly have the fire placed on the fire bricks to spare the biscotto, and to occasionally use the fire brick side for other cooking than neapolitan pizzas. And to some extent to optimize the already blown budget... 

[Jon in Albany]

I'm planning to use biscotto floor in my future WFO (36" low dome, main use neapolitan pizzas), and have luckily found a local supplier of "Biscotto di Sorrento". Have few concerns I would like to get answered first.

• The floor pieces are 40mm (1.57") thick - Is enough thermal mass?
  For domestic use, 1-2 pizzas at the time. Might perhaps put 10-24 mm (0.4-0.95") sand/ash/salt below if that makes any difference.
• I've heard these are quite fragile - Is it possible to cut the pices with an angle grinder without too much problems?
  Square to quarter circles pieces.

I'm also thinking about making 50/50 floor biscotto and high duty fire bricks. For two reasons, to mainly have the fire placed on the fire bricks to spare the biscotto, and to occasionally use the fire brick side for other cooking than neapolitan pizzas. And to some extent to optimize the already blown budget... 

Yes you can cut biscotto with an angle grinder. Just make sure you do it outside. It creates a lot of dust.

I think you want low duty fire brick. In the states, a brand called Whitacre Greer is the firebrick commonly used for ovens.

To try to get a fairly level split floor like you are describing, I used biscotto on top of firebrick splits on one side and whole firebrick on the other. I used fireclay to make the two sides level. When you have the floor laid out how you want it, run a peel over it to make sure none of the joints catch.

Best of luck on your build!

[TravisNTexas]

Yes you can cut biscotto with an angle grinder. Just make sure you do it outside. It creates a lot of dust.

I think you want low duty fire brick. In the states, a brand called Whitacre Greer is the firebrick commonly used for ovens.

To try to get a fairly level split floor like you are describing, I used biscotto on top of firebrick splits on one side and whole firebrick on the other. I used fireclay to make the two sides level. When you have the floor laid out how you want it, run a peel over it to make sure none of the joints catch.

Best of luck on your build!

Thanks for the tip on Whitacre Greer low duty firebrick.  Checked out the web site and there are two distributors in Dallas.  Can somebody explain the difference between low duty and high duty fire bricks in regards to WFO performance please?

[Jon in Albany]

The different grades have different max  temperatures. I haven't done anything with a high duty firebrick but I have read that they are much harder/denser to cut. They are also supposed to be better for really hard abrasive wear and tear like in a factory kiln. Former forum Moderator tscarborough works in the masonry industry and has had good things to say about the Whitacre Greer brand. That was a good enough endorsement for me.

Here is a good write up on bricks that includes a breakdown of the different duties.

https://www.brickwoodovens.com/fire-brick

[TravisNTexas]

The different grades have different max  temperatures. I haven't done anything with a high duty firebrick but I have read that they are much harder/denser to cut. They are also supposed to be better for really hard abrasive wear and tear like in a factory kiln. Former forum Moderator tscarborough works in the masonry industry and has had good things to say about the Whitacre Greer brand. That was a good enough endorsement for me.

Here is a good write up on bricks that includes a breakdown of the different duties.

https://www.brickwoodovens.com/fire-brick

That's an awesome and concise writeup at that link!  Thanks very much for that.

[Ganlet]

Yes you can cut biscotto with an angle grinder. Just make sure you do it outside. It creates a lot of dust.

I think you want low duty fire brick. In the states, a brand called Whitacre Greer is the firebrick commonly used for ovens.

To try to get a fairly level split floor like you are describing, I used biscotto on top of firebrick splits on one side and whole firebrick on the other. I used fireclay to make the two sides level. When you have the floor laid out how you want it, run a peel over it to make sure none of the joints catch.

Best of luck on your build!

I missed to reply to this thread, thanks for your tips. Anyway, my plan has changed so I will go full out with just Biscotto floor to avoid the hassle with mixing.

Could anyone give some feedback on the thickness for the floor? Afraid 40mm (1.57") thick stones are somewhat on the thin side. On one hand, might be handy to have a quick oven, but if it isn't balanced and cant retain enough het for short and long periods the whole purpose going full out with a brick oven is pretty much a waste.

Since I'm building a separated floor/dome I have quite much freedom in the design, but can't decide:

• Only Biscotto 40mm (1.57")  - Risk of not being balanced heat-wise?
• Layer under of 20mm sand - Maybe not enough conductivity and heat storage? I've red it has more of an insulating effect
• Layer under of 25mm fire bricks - The safe bet, but have already put the money on the Biscotto floor.
• Layer under of 20mm Homebrew - Will probably crack a bit, but I guess it will withstand to keep the floor intact and do the job. Quite much work though.
• Layer under of 20mm granite stones - Reasonable price for relatively little work, should work for the task?

[Jon in Albany]

I missed to reply to this thread, thanks for your tips. Anyway, my plan has changed so I will go full out with just Biscotto floor to avoid the hassle with mixing.

Could anyone give some feedback on the thickness for the floor? Afraid 40mm (1.57") thick stones are somewhat on the thin side. On one hand, might be handy to have a quick oven, but if it isn't balanced and cant retain enough het for short and long periods the whole purpose going full out with a brick oven is pretty much a waste.

Since I'm building a separated floor/dome I have quite much freedom in the design, but can't decide:

• Only Biscotto 40mm (1.57")  - Risk of not being balanced heat-wise?
• Layer under of 20mm sand - Maybe not enough conductivity and heat storage? I've red it has more of an insulating effect
• Layer under of 25mm fire bricks - The safe bet, but have already put the money on the Biscotto floor.
• Layer under of 20mm Homebrew - Will probably crack a bit, but I guess it will withstand to keep the floor intact and do the job. Quite much work though.
• Layer under of 20mm granite stones - Reasonable price for relatively little work, should work for the task?

I went with leveling fireclay on top of insulation boards, fire brick splits, then leveling clay as needed under the biscotto. I can't say what is best, this is all I have experience with.

One other thing that I don"t want to surprise you, the firebrick splits I have are about 1.25 inches thick, so closer to 33 mm instead of 25 when you are planning.

[Ganlet]

I went with leveling fireclay on top of insulation boards, fire brick splits, then leveling clay as needed under the biscotto. I can't say what is best, this is all I have experience with.

One other thing that I don"t want to surprise you, the firebrick splits I have are about 1.25 inches thick, so closer to 33 mm instead of 25 when you are planning.

Which thickness did you have on the biscotto, and how would you say the performance is with respect to the dome?

I just realized the biscotto floor I'm looking at is 50mm, so perhaps this is enough thermal mass by itself so I don't need to fiddle with any kind of heart between the insulation board and the biscotto floor. More input is well appreciated before I make final decision

[Jon in Albany]

Which thickness did you have on the biscotto, and how would you say the performance is with respect to the dome?

I just realized the biscotto floor I'm looking at is 50mm, so perhaps this is enough thermal mass by itself so I don't need to fiddle with any kind of heart between the insulation board and the biscotto floor. More input is well appreciated before I make final decision

The biscotto I had was about the same thickness of a firebrick split. The two stacked were some leveling clay more than a firebrick, so it is closer to 1.25 inches/30 mm.

I like the performance but dont have much Neapolitan experience or other ovens to compare it too. I highly recommend well  insulating everything and insulation below the oven floor can't be skipped. So when planning, be sure to include the height of the insulation below the oven floor.

[amolapizza]

FWIW, Italians often use a layer of sand/ash/salt, maybe crushed glass, vermiculite, etc under the biscotto.  I'm not sure about the details, but I've been reading a bit about how they construct their WFOs.

Even if you don't read Italian, this might be interesting in combination with google translate: https://laconfraternitadellapizza.forumfree.it/?f=11224842

[Tscarborough]

If at some point you are going to bake bread, you may want to use split firebrick>fireclay to level>Biscotto floor, otherwise for making pizza, 50mm of biscotto should be fine. 

[Ganlet]

If at some point you are going to bake bread, you may want to use split firebrick>fireclay to level>Biscotto floor, otherwise for making pizza, 50mm of biscotto should be fine.

I'll think I'll skip to go full out to make it a bread oven, that ship has sailed. Rather an regular all-around oven and perhaps sometime just try out some kind of easier bread making or similar.

So right now the decision lies between two options; just the 50mm biscotto on top of the insulation board or cast a 15mm layer of homebrew and level the biscotto on top of this (after drying so it is replaceable).

The first option saves a lot of work, the second I think would be closed to what are field-proven dimensions. In addition it would in my case thermally connect the dome and floor as well as close off the cooking area from insulation board (refractory material feels somewhat sketchy despite the safety declarations) as well as an additional barrier for water to find its way in (based on that the home brew layer doesn't crack for certain).

Anyone believe the additional 15mm thermal mass in this case and thermal connection between the dome and floor are positive and worth the work?

[JConk007]

Where did you find the supplier for Biscotto I am looking !!
Please and Thank you !!
JOhn

[TXCraig1]

Where did you find the supplier for Biscotto I am looking !!
Please and Thank you !!
JOhn

Good to hear from you John. How've you been? I was looking for something yesterday, and I came across this picture: