Soapstone Oven Floor

[Robpriddy]

Just finished my hearth and starting to study details of building the oven. Looked at photos of an oven building workshop and in the photos they used larger pieces of soapstone for the floor of the oven instead of firebricks. Seems like fewer pieces could create fewer edges for catching tools in the oven.

Anyone know if there are any advantages or disadvantages to using soapstone as a substitute for firebricks in the oven floor?

[GianniFocaccia]

Re: Soapstone Oven Floor

Hey Rob,

Don't know the advantages/disadvantages of soapstone firsthand (my oven isn't operating yet) but here's what I've read/seen:

1. Soapstone can withstand oven temps but not forever. I have seen some of the thinner SS floors with cracks in them. This is why I placed the dome outside the floor

2. SS in larger pieces (I have three slabs) leaves fewer edges and opportunities to catch a peel

3. Dark SS will not reflect as much light as a lighter-colored firebrick, making the oven appear darker inside

4. SS is expensive unless you got a hook-up

5. SS conducts heat (both heat-up and cool-down) faster than firebrick. For this reason, it has been reported that SS is less-than-desirable for baking bread, but I think there are workarounds for this

6. A number of commercial ovens use soapstone because it recharges quickly

I plan to cook a number of dishes in pans using the soapstone floor as a heating 'element' with a fire going like I saw at the First Annual FB Expo. That plus pita breads with dinner

John

[Stevenb]

Re: Soapstone Oven Floor

This is the soapstone we use. If you can find nice black soapstone you are pretty good. We have used green like this several times. It costs $7-900 for it all cut to our template. We use three pieces. It goes in super easy, but can crack over time. We never take it out so the cracks don't move or cause mush issue. Besides. Two cracks are far better IMO than the joints between 60-80 fire bricks. The thing to avoid is the talc, or white veins in the slab if you can. Good luck.

[deejayoh]

Re: Soapstone Oven Floor

It costs $7-900 for it all cut to our template

I think that just about sums up the main disadvantages. Soapstone is great if you are made of money but most builders on this forum are looking to save a little coin. I put soapstone in the entry of my oven, which cost about $75 cut to size. I did that mostly for aesthetics.

FWIW Firebrick floors use about 30 bricks, not 60-80, if it matters.

[scott123]

Re: Soapstone Oven Floor

Soapstone is a poor choice for an oven floor. My reasons are here:

http://www.fornobravo.com/forum/8/so...tml#post128810

We never take it out so the cracks don't move or cause mush issue. Besides. Two cracks are far better IMO than the joints between 60-80 fire bricks. This is the soapstone we use. If you can find The thing to avoid is the talc, or white veins in the slab if you can.

The talc lends conductivity to soapstone, making it more thermally durable. I don't recommend soapstone, for the reasons stated above, but, if you were intent on incorporating it, talc is an advantage, not a defect.

Also, the odds are probably in your favor, but it's not the best idea to bake on a cracked hearth. The thermal forces that generate cracks don't always create clean breaks and can weaken other areas that my not be visible. This increases the chances of shards breaking off and getting into food. Soapstone is one of the softer stones, but it's not softer than teeth.

[Stevenb]

Re: Soapstone Oven Floor

I think that just about sums up the main disadvantages. Soapstone is great if you are made of money but most builders on this forum are looking to save a little coin. I put soapstone in the entry of my oven, which cost about $75 cut to size. I did that mostly for aesthetics.

FWIW Firebrick floors use about 30 bricks, not 60-80, if it matters.

I don't know what size ovens you build, but ours are 36" inside diameter and, with using the brick to extend to the outside of the dome walls we use over sixty. As to the cost, pizza ovens aren't a cheap item. Just buying materials for the ovens with the base, walls, insulation and everything else costs close to $4000 around here. Granted, we do use two full layers of the woven ceramic around the dome and do a very thick layer of flexible stucco over the whole top. The floors are amazing and everyone we've put in for people has gotten nothing but praise from the homeowners.

[Stevenb]

Re: Soapstone Oven Floor

Soapstone is a poor choice for an oven floor. My reasons are here:

http://www.fornobravo.com/forum/8/so...tml#post128810



The talc lends conductivity to soapstone, making it more thermally durable. I don't recommend soapstone, for the reasons stated above, but, if you were intent on incorporating it, talc is an advantage, not a defect.

Also, the odds are probably in your favor, but it's not the best idea to bake on a cracked hearth. The thermal forces that generate cracks don't always create clean breaks and can weaken other areas that my not be visible. This increases the chances of shards breaking off and getting into food. Soapstone is one of the softer stones, but it's not softer than teeth.

I am talking about talc veins. Not talc in general. Sorry if I was unclear. I talked to suppliers in India and overseas, and was told by them to avoid talc (veins), because they cause weak points and breakage. We used one piece with veins and it cracked, but has not moved. I use soapstone in my house and have had it for five years. It makes amazing pizza at 500 degrees. Our oven users cook at 800-850 degrees oven temps after eating for several hours and we have yet, out of dozens of pizza parties, and probably hundreds of pizzas, had any burned pizzas.

[GianniFocaccia]

Re: Soapstone Oven Floor

I paid $10/sq' for my soapstone, which came out to less than $200 for a 39" oven.

[Stevenb]

Re: Soapstone Oven Floor

I paid $10/sq' for my soapstone, which came out to less than $200 for a 39" oven.

We have gotten several different prices through the last couple years. Anywhere from $450 to $900

[deejayoh]

Re: Soapstone Oven Floor

I don't know what size ovens you build, but ours are 36" inside diameter and, with using the brick to extend to the outside of the dome walls we use over sixty. As to the cost, pizza ovens aren't a cheap item. Just buying materials for the ovens with the base, walls, insulation and everything else costs close to $4000 around here. Granted, we do use two full layers of the woven ceramic around the dome and do a very thick layer of flexible stucco over the whole top. The floors are amazing and everyone we've put in for people has gotten nothing but praise from the homeowners.

Well, since you brought it up - the math is pretty easy. Area of a 36" oven is ~1020 sq inches. (Pi-R-Squared)

Standard firebrick at 9 x 4.5 = 40.5 inches area

Simple division - 25 bricks for a floor. That's about $50 or 60. Even if you add another 4.5 inches to the radius to go under the dome, its only 39 bricks. I don't question that your soapstone floors perform - but using your figures, soapstone floors will easily add $500, which 20% to the cost of a finished oven. I don't think most people find the performance difference worth the cost.

[Stevenb]

Re: Soapstone Oven Floor

36" oven plus 9" to reach out to the outside of the oven plus the throat. I've built 5 so far. How about you. I think I know how many it takes. How many ovens have you built and how many customers have you had constant feedback from for 3-4 years on a monthly basis? Every single one started with fire bricks, and every one has since had us add soapstone. Every single one is much happier with cooking performance and ease of cleaning, maintenance, and heat retention over the fire bricks. Why would you want to cook on porous bricks and dozens of seams, when, if you can afford it, soapstone has two seams.

I'm not saying your opinion doesn't count, but your opinion and mine are different and that's what this person asked for. Opinions. I gave mine, you don't agree with it or like it. So be it. Hope your oven is what you like and enjoy. I know the ones I've built make their owners happy several times a week.

[shuboyje]

Re: Soapstone Oven Floor

Here is the floor from the CAD drawing of my most recent oven. By my rough count it would take about 36 Full Bricks to make this floor as Drawn, and this is a 42" oven. For some reason I feel like I ended up using 38, but would have to check my records. Regardless, far from 60-80.

[Tscarborough]

Re: Soapstone Oven Floor

I would use soapstone brick in a minute if they were at all cost competitive, but the difference in thermal characteristics is not worth the premium (unless money is no object, of course).

Note that I said "brick" not "slab", I prefer my cracks to be pre-engineered.

[Stevenb]

Re: Soapstone Oven Floor

Here is the floor from the CAD drawing of my most recent oven. By my rough count it would take about 36 Full Bricks to make this floor as Drawn, and this is a 42" oven. For some reason I feel like I ended up using 38, but would have to check my records. Regardless, far from 60-80.

We run our fire brick out the throat also. Ours is also 45" possibly a tad bigger. We used more on the first oven because the homeowner wanted the brick to extend out to cover the entire deck. Against our judgement and recommendations. Why is everyone so concerned and obsessed with proving my number wrong? I don't understand lol. I am just saying how many we have used.

[Stevenb]

Re: Soapstone Oven Floor

I just looked up a photo of the last one we built, and counted 57 bricks plus partials. No cad drawing. No math. Counting what we used.