floor tiles

[dusty]

Re: floor tiles

James,
How would you describe this "expantion gap" between the floor and dome. Just an empty space?

dusty

[dmun]

Re: floor tiles

Very interesting thread since I would prefer to use floor tiles too. However I wasn't totally clear what exactly are used for the floor tiles. Is it the Super Isol tiles, and you then cook directly on them? I couldn't see any other tiles in the shop.

Welcome Mikeintj. Most home builders make their floors out of firebrick, laid flat, usually without mortar. There are other floor options. Modular ovens have floors that come in sectors, and are solid pieces of refractory material. There are also things called "refractory tiles" that come from the furnace industry, and basically are big flat pieces of firebrick. Since they are specialty items, they are a lot more expensive per square foot than firebrick. I've even seen oven floors made of slabs of soapstone.

Whatever your oven floor is, it should be a hard refractory (heat proof) substance, to absorb and reflect the heat of your fire. There should be an insulating layer underneath, to keep the floor hot and prevent heat leakage. This can be vermiculite/perlite concrete, or an insulating board like super-isol. This choice is a cost/space one: both work well.

You would never build an oven to cook on the insulating layer directly. It wouldn't hold the heat. It's also porous, and would absorb oven junk, which with a brick oven burns away with your next fire.

[mikeintj]

Re: floor tiles

Very interesting thread since I would prefer to use floor tiles too. However I wasn't totally clear what exactly are used for the floor tiles. Is it the Super Isol tiles, and you then cook directly on them? I couldn't see any other tiles in the shop.

[Dutchoven]

Re: floor tiles

If the floor is inside the oven it heats up faster and stays hotter longer because it is inside the oven. One could also think of it this way, you are not heating any part of the floor that is not potential cooking surface. When I constructed my oven(barrel vault) I placed it on top of a floor of bricks set on edge as opposed to the flat side as is suggested in the FB Pompeii plans. This gave me additional thermal mass for baking and did not really increase heat up time that much. By contact the floor bricks on the outer edges(the ones that are under the walls and such)get hot but, do not give much of that heat back to the oven chamber. That, at least, is my thinking on the topic.
Best
Dutch

[RCLake]

Re: floor tiles

[QUOTE=james;6673]Les,

As a rule, it is better for the dome to rest around the cooking floor, not on it. That design offers better heat retention and cooking, and gives you more flexibility with the floor itself. The floor becomes a discrete piece of the oven, not that on which everything sits.


I don't understand why the heat retention would be different whether the dome is on top of the floor or outside of a circular floor. It seems to me in either way of construction that area is firebrick. I agree with the flexibility given the outer ring could be replaced is broken if the dome is on the outside. Dwight

[Marcel]

Re: floor tiles & Pizza Pi

More Pizza Pi

(DL) ?OK, Given all dimension are the same, and thinking of the oven as a unit, there is no difference between the dome resting on the floor bricks and the oven resting on the insulation/concreate hearth.?

(M) I hope not to make things simpler than possible but I have to agree with dlachez that looking just in terms of volume, and heat retention that the two structural approaches would probably have differences too small to measure.

(M) I think it is important in our building discussions to make a clear distinction as to whether we are building the dome from scratch, or whether we are buying pre-cast commercial oven parts such as offered in the FB Modena oven.

(M) In the case of those commercial ovens it is clear that resting the dome AROUND and not ON the floor tiles makes sense because if it were placed on that circle of bricks the least movement could cause the dome to become eccentric.

(M) On those ovens built from scratch, because of the difficulty of cutting the perimeter floor bricks in a circle those floor bricks invariably extend beyond the dome?s circumference enough that the dome would never become eccentric even without applying mortar to the bottom of the first course.

(M) The original Forno Bravo plans have been changed in several ways since I first followed those instructions. As an example, I was instructed to first pour the insulating layer and then have the floor bricks resting on a thicker layer of refractory concrete. We can?t get something for nothing. In my case, the old layering means I need to wait longer before my oven gets hot, but the offset is that heat stored in my top layer of refractory concrete continues to radiate and gives that order of insulation and then refractory concrete an advantage in baking bread. Those who follow ?The New Order? are those whose main priority is pizza pi.

(DL) ? (to tell the truth I have a problem with calling the concreate and pearlite base the oven rests upon but that is another a thread, a hearth is were the fire burns, sorry I'll stop now.)?

(M) I think you have a valid point. I previously advocated a very controlled vocabulary for the building plans. Here are the terms, starting from the earth up that I like to use:

1-Foundation Slab
2-Hearth Stand
3-Hearth Slab (2 layers, in whatever order the builder prefers)
4-Refractory Brick cooking floor (recommend a 45 degree true herringbone)
5-Refractory Brick Dome (starting course in whatever preferred orientation)

Other terms could be: MANIFOLD for that part of the oven that focuses smoke up the FLUE. The MANIFOLD could be made of sheet metal, cast refractory concrete, bricks, ?

The FLUE can be made of metal tubing such as exits from interior wood burning stoves, chimney tile, but preferably not paper maiche!


Of course the dimensions can't be exactly the same the curve will be different but come on we are talking about a 2.25 inches as applied to pi. Right?

(M) Sounds right to me. Enjoy your Pizza Pi !

Chow,

Marcel

Re: floor tiles

OK, Given all dimension are the same, and thinking of the oven as a unit, there is no difference between the dome resting on the floor bricks and the oven resting on the insulation/concreate hearth. (to tell the truth I have a problem with calling the concreate and pearlite base the oven rests upon but that is another a thread, a hearth is were the fire burns, sorry I'll stop now.)

Of course the dimensions can't be exactly the same the curve will be different but come on we are talking about a 2.25 inches as applied to pi. Right?

[maver]

Re: floor tiles

Marcel, my floor is yellow refractory brick laid in a true herringbone pattern at 45 degree thrust from the peel. I never catch the peel on brick - it's quite smooth. I cannot tell if the grit is from mortar or brick - whenever I have encountered grit it is very fine - I would mistake it for cornmeal if I didn't know better (I never use conrmeal). As I said on my last post, it's been less of an issue lately as I've been more careful to brush the floor with each pizza and have avoided letting the rake (garden hoe) knock around on the floor. If I ever do clean out the inside thouroughly I'll be able to determine if this is minor residual left over building debris or whether it's continuing to form.

In my case it's a minor problem that I have noticed mostly in the past. I only brought it up because I think it would become a major problem if the oven floor was constructed with a layer of refractory cement 'smeared' over refractory brick as was proposed.

[Marcel]

Re: floor tiles

(M) Maver, is your floor of red standard brick or yellow refractory brick? ___

(M) Did you lay your bricks at 45 degrees to the thrust of your peel? ___

(M) Are those floor bricks in a true "herring bone pattern? ___

(M) Are you able to differentiate the grit as coming from either mortar or bricks? ___

Thanks, and

Ciao,

Marcel

[maver]

Re: floor tiles

I don't know quite where the source was, either from grinding, small amounts of mortar spalling from the dome, or the oven rake (a slightly over heavy garden hoe) knocking off small bits, but I've had grit (very fine but still detectable) get into the pizza crust on occasion. I've been more careful with rake and with brushing the surface since and I think it's a controlled problem. At some point I need to do a good interior clean out so there shouldn't be any more loose material in there.

[Hendo]

Re: Grit from ground floor bricks

On the issue of achieving a smooth floor, I have noticed references to a concrete surface grinding wheel (not an angle grinder) which could be used to smooth out any high corners or edges of the hearth bricks after they are laid. While this seems like a good idea, is it possible that the food will pick up refractory grit from the ground surfaces?

Have any members had any experience of food picking up refractory grit from ground surfaces, whether an angle grinder or a concrete surface grinding wheel was used? While I lilke the idea of a flat floor, I don't really want to eat refractory grit in my pizza!

Paul.

[artigiano]

Re: floor tiles

I did the wash to get into all the little crcka, but as James was saying its not nescessary.. when the bricks are that tight I dont think you need to do a wash, but it couldnt hurt.. just not sure how much of a difference it will make

[carioca]

Re: grit

Thanks Maver, got your point - actually I WAS thinking about applying the 'wash' to the top surface of the hearth bricks... So that's another no-no, then.

Happy holidays to you and all!
Carioca

[artigiano]

Hey guys,

I previously used this stuff called bondset. It is a refractory mortar, and is kind of like a glue but takes a long time to dry and I think the heat from firing up the oven is what allows it to fully cure. I was able to achieve a nice level surface and I actually used this stuff throughout the whole dome. In this sand and fireclay mix what would the ratio be? I heard something like 9:1 but that seems like a lot of sand? Also how thick should this layer of sand/ fireclay be? The bondset I used was around 1/4 inch over the refractory concrete that had the vermiculite insulation. What do you think of my approach for the home oven? I have no complaints a very level surface using individual bricks not even floor tiles... but was wondering if there are added benifits other than a level surface when using the sand/ fireclay mix?

[Hendo]

Grit

On the issue of achieving a smooth floor, I have noticed references to a concrete surface grinding wheel (not an angle grinder) which could be used to smooth out any high corners or edges of the hearth bricks after they are laid. While this seems like a good idea, is it possible that the food will pick up refractory grit from the ground surfaces?