The real thing however, is that indoor kitchen ovens can't be cranked up high enough heat-wise. You are lucky to get close to 600 degrees at broiler setting. Now, your backyard grill, fueled by real lump charcoal will get much hotter. So if you fit tiles or stone on the grill grate you can turn out some pretty amazing pizza or flat bread type things.

I used terracotta tiles when I lived in San Diego and the untreated were easy to find - but they were more fragile. Now I use a baking stone that I just always leave in the oven (evens out the heat since it radiates the ambient temp). The one that's in there now has been in for two years and rarely comes out. I have found the heavier ones (14x16 - don't like the 14"round) worth the cost and I am certain of their content. I bake all my breads on it and would not be with out it.

Yes, I understand that's the kind of tile desired here. I was simply suggesting that AntoniaJames make sure that's exactly what she's getting, from wherever she makes her purchase...that's all.

The tile were talking about are clay and water. Thats it. No dies or additives. Thier made in a field where they mix the clay push into a mold and set in the hot desert sun for months.

The only advice I'd give (as an architect and cook,) is to be careful about what's in the tile you buy - obviously you don't want glazed tile (possible lead content), but also some clay tile contains other additives - dyes (possibly even for subtle 'natural' colors), chemical hardeners, etc. I'd imagine some of these things could be toxic, especially when heated. So, I'd just suggest purchasing it at a good building supply/tile vendor that can vouch for the tile containing nothing but pure terra cotta clay.

The larger ones work better for bread not having to deal with 1 inch gaps between them. I can do long baguettes three in a row on one 18x18 tile.

No matter what you call them, you're looking for unglazed terra cotta, just like flowerpots. Make sure it's made from terra cotta (clay) only--don't purchase anything that contains concrete or cement. Nothing as thick as a brick; 3/4" to 1" is sufficiently thick for home-oven baking, and they'll take about a half hour to 45 minutes to preheat. Before using them, just wash the dust off--don't seal them or season them with anything. You might find smaller tiles to be easier to handle than large ones. Line one of your oven racks with them, leaving an inch around all the sides for heat to circulate.

You might find this discussion interesting:
http://slice.seriouseats.com/archives/2010/02/how-to-make-a-cheap-pizza-stone-from-quarry-tiles-at-a-home-center.html

Yes mine are unglazed and I have also heard the term spanish pavers as well. I found my 18X18 in a tile store in Santa Barbara, Ca. I was remodeling my spanish style home and used the 18x18 through out. I had a case of 18x18 left over and kept them for this reason and gave them to friends as well. I've brought them with me and have been using these for 10 years. I check a local home depot her in Oregon and have not found the 18x18 there. Troubling in case if I want more. Good luck.

Are yours unglazed? Do you seal them or do anything else before using them? The terra cotta we have on our first floor and out to the patio, incidentally, we've heard described as "Spanish pavers." Wonder if there is any difference. 18 x 18 sounds really handy. I was thinking about getting a variety of sizes and shapes, to mix and match depending on my use for them. ;o)

The ones that I use are refered to as mexican pavers and others I have seen with a little different color are called Italian pavers. They work great. Especially if you can find the 18'x18" ones and not the 12"x12" although they will work.