moist clay

[masuzzu]

The video calls for pavers as a base. Here in the US, pavers ae"granular"
or cement like.
Question: are the pavers one and the same?
Thanks!

[dmun]

I don't want to get into any arguments.

The PDF linked to shows in both text and illustration a row of angle irons, supporting a half inch piece of cement board, with a thick layer of crushed stone, a thin layer of sand, and the floor of the oven. No insulation. If this is wrong, it should be corrected, before new oven builders make mistakes based on incorrect information.

It also clearly shows the flue inside the dome of the oven, instead of in the entry. I know that there are some rustic ovens that do this, but this is not a good idea. It prevents proper air flow for heating the oven up, and once the door is in place for retained heat cooking, it leaks all the heat out of the oven. Again, if this is a mistake that the illustrator of this two page document has made, it should be corrected before new builders make mistakes and come here saying that their ovens don't reach temperature, no matter how much wood they burn. This has happened again and again. We tell them that perhaps they can put some insulation below their support slab (which this oven doesn't have, btw) and maybe it will heat up more but really, what they need to do, is to do it over.

I'm just concerned about new builders, and their getting information that will work for them.

[RTflorida]

A 240 mm "heat bank"??? That is 9.45 inches to the metric challenged. ABSURD!!! I'm sorry, there simply is no justification for using this building technique in todays modern age. Hundreds of our members have proved that a 2"-2 1/2" hearth that has good insulation, is more than capable of doing overnight bakes and casseroles. I can put a roast or chicken in my oven the next day, after making pizzas the night before.....Thats 12-14 hrs later and the temp is still 350-400 F with a non-insulated door.
You mention the costs - come on, the cost difference is negligible when you take into account the time and hard work it takes to build an oven. Brickie sand and crushed granite are not free, shop around and you can find perlite/vermiculite or Cal sil type insulation board in the quantity needed for hearth insulation for $50-$75 - Money VERY WELL SPENT.
Based on just the folks who have joined this site asking for help with their un-insulated or under insulated hearths and are totally frustrated that they can't get their oven up to temp concerns me enough to address the insulation BEFORE my oven is built. Many frustated members have stated they have burned their oven for 3-5 hrs and still can't match the 500-550 degrees of their indoor gas or electric oven - that takes A LOT of wood. How many people are out there with ovens that they have given up on and have not found this site?
This building technique may be the way things were done 50, 100, or 500 yrs ago, but it simply does not make sense TODAY....Personally, I really appreciate authenticity, but not at the cost of performance. I didn't bust my butt for 3 months to produce Dominos/Pizza Hut quality.
Cost/expense is not a valid excuse, the costs to insulate the entire oven (dome and hearth) simply are not that high.

Sorry for the rant, I will get down from my soap box now. No personal attacks intended, just my 2 cents towards the debate. I, like dmun, simply don't want any new members to get any ideas that have been proven to be outdated or ineffective. We want to grow the WFO culture, not create a disgruntled community with giant masonry paper weights sitting out back.

RT