Building on porcelain tile?

[Jim Voorhees]

I plan to pour 4" refractory concrete base for Pompeii oven on existing BBQ structure where room is available. Any problem with pouring on the existing porcelain tile.

[UtahBeehiver]

Maybe explain what you mean by refractory concrete base. What exactly are the layers both existing and new, how thick and what materials and what purpose do you envision. IE support, insulation, etc. A pic would help too.

[Jim Voorhees]

Thanks for the reply. Hope photos are attached. This is all new for me. The BBQ was built for NE Ohio winters and has been in use for about 15 years. 8" concrete bloc faced with extra house brick and 21/2" poured high strength concrete with all reinforcing. Installed porcelain tile top two years ago. Intend to pour about 4" insulating concrete 5:1 vermiculite:Portland cement per Pompeii Oven Instructions pg 31. Intent is for fast temp rise oven for pizza mainly but would also use for breads and meats (small scale stuff). Porcelain has been 100% stable winter to summer so I think it should be fine but would be interested in experienced thoughts. I have noj idea what heat to expect to reach the porcelain.

[UtahBeehiver]

How large of an oven are you looking and what type, ie brick, cast, etc. These oven can get really heavy quickling and the 2 1/2" hearth is a little concern depending on oven size and span of hearth. the tiles, as long as the are in good shape and should not pose a problem to pour a vcrete layer directly on top. 4" of 5 to 1 vcrete (abt equal to 2" of CaSi board) is the minimum thickness for the cooking requirements you listed out. I doubt you will see temps on bottom of vcrete that will affect tiles as long as it is dried out properly. I was confused when you said refractory cement vs vcrete, they are two different animals.

[Jim Voorhees]

The oven hearth will all be well supported by the bloc and brick structure. The size is still being considered. The base is what it is so I either have a smaller oven (29") with thick brick walls or 32" with thinner brick walks. I will not looking for extended cooking so much as I want something that will heat up faster. I'm inclined to go for a 32" with thinner brick walls. I"ll be going with standard insulation recommendation for Pompeii oven and finish with a stucco exterior.

[Jim Voorhees]

Finally getting started on this oven project. I poured a insulated slab for the oven to be constructed on. Should I wait four weeks before beginning the first course? I just removed the form after a one week cure period. Also haven't figured out how to add pictures from my iphone photos app. correctly. Where can I read the correct procedure for adding pictures.

[david s]

To assist water elimination from the insulating slab a few holes drilled through the supporting slab will help the moisture escape. See attached experiment for the drying of the vermicrete slab.

Vermicrete insulating slab copy.doc.zip

[Jim Voorhees]

Purchased saw and cutting my bricks. Is there a way to figure the angle cut needed for subsequent rows as rows wrap inward? Trial and error? Also had a mason tell me once that finish brick on chimney should not contact clay liner, but read reply in a post to fill or parge with home brew. What is the proper way to handle the oven flu. Also saving residue from cutting medium density fire brick. Read where this can be used to replace some clay. Is it better than clay and should I supplement in any one area over another or just evenly distribute over entire build?

[UtahBeehiver]

Deejayho did an Excel Spreadsheet that calculates the angles and gets you in the ballpark. Search under his threads. You can also look at JR Pizza threads, he uses and option of only beveling the top inside corners of the joints and not tapering (angle) the brick. On the clay flu and outer brick gap you can either install a p/vcrete insulating layer. You can use brick cuttings but there have been several reports that the homebrew mortar is harder to work with than clay which is cheap anyway.

[Jim Voorhees]

Not familiar with what p/vcrete is or how to go about searching for threads but I do appreciate the assistance. I tried searching for the names you provided but "no luck".

[UtahBeehiver]

I thought in your previous post that you were installing 5 to 1 perlite/portland (aka pcrete).

[Jim Voorhees]

I am considering my options of laying the floor and build the first chain on the floor or building the first chain and cutting the floor to fit inside the first chain. What seems to be the prevailing option and the logic. What is done to fill any minor gaps in the inlaid method?

[Chach]

I built my oven on the around the floor. I like the fact that I can replace any floor brick if I needed to but may never have to. The gaps fill with ash from your wood burns. I also like that the floor and the walls are seperate as they may move slightly during heat up and cool down although minimum I like that I have that expansion gap there. Just my preference.

Ricky

[Jim Voorhees]

Nearing building chimney point and recall reading somewhere about insulating chimney from oven but cannot relocate item. Is this done to prevent heat being pulled from oven? Can someone point me in the right direction to find information as to location of insulation, materials to use, etc.? Thanks